Lizards

Question 1

What are the two large subgroups of lizard taxonomy? What families are within each group?

Answer 1

Iguania

• Agamidae
• Chamaelionidae
• Iguanidae

Scleroglossa

• Nyctisaura - Gekkonidae, Amphisbaenidae (worm lizards)
• Diploglossa
  
  • Scincidae - largest family
  • Anguimorpha
    
    • Anguidae - glass & legless lizards
    • Varoindae
      
      • Helodermatidae
      • Varanidae
      • Lanthanotidae - earless monitor lizards

Question 2

How do lizards shed? What factors affect shedding?

Describe the glands found in lizards. Are they sex-linked?

What provides the pigmentation to the skin in lizards? What are they composed of?

What species have osteoderms?

How do gecko’s climb so well?

Answer 2

1. Integument
   
   1. Thick, keratinized skin with ectodermal scales (formed by folding of the epidermis and outer dermal layers)
   2. Lizards typically shed in small pieces - exception is geckos that shed all at once
   3. Factors that affect shedding:
      
      1. Species, size, temperature, humidity, state of nutrition, age, sex, growth rate, skin damage (trauma, surgery, infection), health status, endocrine factors
   4. Glands are more developed in males
      
      1. Femoral pores in iguanas and many agamids
      2. V-shaped pre-cloacal glands in many geckos and agamids
         
         1. Not true glands, just skin invaginations that produce waxy substance
   5. Chromatophores change size and positioning in the dermis some species (chameleons, anoles)
      
      1. Melanophores - melanin
      2. Erythrophores
      3. Xanthophores - pteridines, carotenoids
      4. Iridophores - reflective platelets of guanine, adenine, hypoxanthine, urica cid
   6. Osteoderms are dermal bones that support epidermal scales
      
      1. Present in Heliodermata and some skinks, legless lizards, and girdle-tailed lizards
      2. Gecko feet have adhesive setae for climbing

Question 3

Describe the anatomy of the lizard heart.

Describe the flow of blood through the lizard heart.

Where is the heart located? Does it vary by species?

Describe the renal portal system. How is it clinically relevant?

Answer 3

1. Cardiovascular System
   
   1. Three chambers = right atria + left atria + single ventricle
   2. Single ventricle = cavum venosum + cavum arteiosum + cavum pulmonale
   3. Blood flow: Venous blood → right atrium → cavum vensoum → cavum pulmonale → pulmonary artery → lungs → left atrium → cavum arteriosum → atrioventricular valve → cavum venosum → aortic arches x 2
   4. Heart is within the pectoral girdles except monitors and tegus, where it is more caudal
   5. Renal portal system: blood from the tail and some from the hind limbs flows directly to kidneys
      
      1. Decreased serum concentration if you inject drugs that are cleared via tubular secretion in the caudal half of the body, but unknown clinical significance
      2. Can increase nephrotoxicity of aminoglycosides administered in the caudal half of the body
      3. The postcava can shunt blood past the kidneys
   6. Baroreceptor control of hypotension is not affected by temperature
      
      1. Normal blood pressure in brumation

Question 4

How do salt glands work? What species have them?

How does glottis location vary by species of lizard?

What kind of tracheal rings do lizards have.

Describe the lung anatomy of lizards. How does it vary by species - Skinks, Varanids, Chameleons?

How does inspiration occur without a diaphragm?

What is unique about monitor respiration?

What stimulates lizards to breathe?

Answer 4

1. Respiratory System
   
   1. Nasal salt glands in herbivorous iguanids excrete concentrations high in Na and K
      
      1. May be more important for osmoregulation than kidneys
   2. Glottis is rostral in monitors caudally in agamids
      
      1. Closed only during inspiration and expiration
   3. Incomplete tracheal rings that bifurcates at the level of the heart
   4. Lungs
      
      1. Primitive Lizards have a hollow single chamber lined with faveoi (spongelike)
      2. Skinks have large caudal nonrespiratory sacs that are thin-welled and poorly vascularized
      3. Advanced lizards have interconnected chambers that are divided by a few septae
         
         1. A membrane connects to the pericardium
      4. Chameleons have hollow fingelike projections at the margins of the lungs
         
         1. Used for inflation, not air exchange
      5. Monitor lizards have multiple lung chambers and primary and tertiary bronchi
   5. Inspiration is voluntarily controlled by intercostal muscles and coelomic wall muscles
      
      1. No diaphragm but monitors and gilas have a fascial layer to separate thorax and coelom
      2. Require ventilation when anesthetized
   6. Monitors have unidirectional airflow
   7. Fluttering of the ventral throat moves air in oropharynx for cooling and olfaction
      
      1. No a significant part of respiration
   8. Control of Respiration
      
      1. CO₂ and O₂ chemoreceptors in periphery
      2. Increased CO₂ (not O₂) is the primary drive to breathe
      3. Pulmonary stretch receptors suppress inspiration and increase expiration

Question 5

What are the two dental patterns of lizards? List the families that have each type.

What lizards have venom?

Describe the intestinal anatomy of herbivorous lizards.

Is stone ingestion normal?

Describe the appearance of the liver. What process may lead to a light gray appearance?

Answer 5

1. Digestive System
   
   1. Dentition
      
      1. Pleurodont: teeth attached to the lingual side of the mandible without sockets
         
         1. Iguanids and varanids
         2. Shed and replaced (odd-numbered teeth, then even-numbered)
         3. Periodontal disease has not been reported with this dentition
      2. Acrodont: teeth attached to the biting surface of the jaws without sockets
         
         1. No replacement, though may add some to the back as the animals grows
         2. Agamids and Chamaeleonidae
   2. Gustatation
      
      1. In fleshy tongues, many taste buds in tongue and in pharynx
         
         1. Protrusion of tongue controlled by hyoid apparatus
      2. Monitors and tegus have a keratinized tongue with few taste buds
      3. Forked tongues bring scent particles to vomeronasal (Jacobson’s) organ
      4. Tip of agamid and iguanid tongues is naturally darker (not a lesion
      5. Paired openings to vomeronasal organ at the roof of the mouth
   3. Venom
      
      1. Gila monsters and Mexican beaded lizard have sublingual venom glands that indirectly move venom into prey through grooves in the teeth with mastication
      2. Symptoms: pain, hypotension, tachycardia, nasua, vomiting
      3. Some varanids and iguanas also have venom that affects coagulation
   4. Stomach
      
      1. C-shaped with a fundic and parapyloric regions +/- cardia +/- rugae
      2. Stone ingestion is not normal - except in marine iguanas
   5. Intestines
      
      1. Herbivores have long intestines and an obvious colon
      2. Species with a large, sacculated colon for fermentation: green iguana, prehensile-tailed skink, Egyptian spiny-tailed lizard, and chuckwalla
   6. Cloaca = coprodeum (collects feces) + urodeum (urinary waste and sexual structures) + proctodeum (final chamber before the vent
      
      1. Cloacocolonic region is important for reabsorption for electrolytes and fluids from feces
   7. Liver is bilobed (R>L) with a gallbladder
      
      1. Some lizard species may have a disant gall bladder (similar to snakes)
      2. Normal mahogany color - chronic disease increased melanomacrophages create light gray appearance.

Question 6

List at least 5 dimorphisms that may indicate a lizard is male.

How can you confirm?

What is the groove that sperm travels down in the hemipenes?

Parthenogenesis is reported in what lizard groups?

Answer 6

1. Reproductive System
   
   1. During breeding season, testicles increase in size and males are more aggressive
   2. Signs that your lizard may be a boy:
      
      1. Taller dorsal spine
      2. Larger dewlap
      3. Larger operculum scales
      4. Elaborate head ornamentation (chameleons)
      5. Brighter colors
      6. Larger body size
      7. Hemipenal bulges
      8. Enlarged femoral and precloacal pores
   3. Ways to evaluate for hemipenes:
      
      1. Probing
      2. Eversion with gentle pressure (avoid in lizards with tail autonomy)
      3. Transillumination
      4. Radiograph for possible calcification
      5. Hemipene contrast radiography
      6. Ultrasonography
   4. Male Sex Organs = testes, epidymides, vasa deferens, hemipenes
      
      1. Sulcus spermaticus = groove in hemipenes that sperms run down into the female
      2. Retractor hemipenis = muscles that retracts everted hemipenes after copulation
   5. Female Sex Organs = ovaries, oviducts
      
      1. Internal fertilization
      2. Sperm storage can occur
      3. Can be oviparous or viviparous
   6. Parthenogenesis: female gamete develops into a new individual without being fertilized by a male gamete
      
      1. Occurs in several all-female species of lizards
      2. May be an incidental occurrence in other lizard species, like Komodo dragons
      3. Parthenogenesis reported in lizards, especially Cnemidophorus
         
         • Gekkonidae and Komodo dragons can also reproduce asexually

Question 7

Where are the kidneys located in lizards? Does this vary?

What renal structures are missing?

What groups of lizards have a sexual segment?

What lizards lack a urinary bladder?

Answer 7

1. Urinary System
   
   1. Metaneprhic, paired, elongated, and slightly lobulated
      
      1. Lack a loop of Henle, renal pelvis
      2. Have fewer nephrons than mammals
   2. Located retrocoelomically in dorsal coelom (chameleons, varanids) or in pelvic canal (agamids, iguanids)
   3. In some male geckos, skinks, and iguanids, posterior kidney is called the sexual segment because it has distal tubular hypertrophy, becomes swollen during breeding season, and contributes to seminal fluid
   4. Reptiles can excrete nitrogenous waste as…
      
      1. Uric acid - primary route
      2. Urea: High water loss
      3. Ammonia: High water loss
   5. Bladder
      
      1. Urinary waste cannot be used to determine renal function
         
         1. Urine cannot be concentrated about plasma
         2. Bladder can absorb water
      2. Lacking in some agamids, varanids, Crotophylus, Cleropus, and geckos
         
         1. Urine stored in distal colon
      3. Urinary waste is not sterile because it flows into the urodeum, then the bladder

Question 8

How does the lizard manidble differ from the snake mandible?

How does legless lizard anatomy differ from snakes?

How many phalanges on each toe?

What is unique about chameleon feet?

How does tail autotomy occur?

Answer 8

1. Musculoskeletal System
   
   1. Fused mandibular symphysis (unlike in snakes)
   2. Legless lizards have lost leg long bones but retained pectoral and pelvic girdles
   3. Phalanges
      
      1. Front: 2-3-4-5-3
      2. Hind: 2-3-4-5-4
   4. Chameleons have zygodactyl feet with digits 1,2, and 3 opposing 4 and 5
   5. Development of fracture planes associated with autotomy and regrowth of tail in several species
      
      • Autotomy can occur at various levels except where caudal vertebrae are associated with extrinsic caudofemoralis longus muscle (primary extensor of the hip joint) and cranial tail where hemipenes, fat deposits, and other structures are present.
      • Regenerated tail skin is generally darker, muscle is pale and lacks well defined septa and quadrants
      • Caudal vertebrae are replaced by a cartilaginous tube that may become mineralized but vertebral bones do not regrow

Question 9

How many cranial nerves do lizards have?

How does the spinal cord anatomy differ from mammals?

Answer 9

1. Nervous System
   
   1. Brain: Forebrain + hindbrain
   2. 12 cranial nerves
   3. Spinal cord extends to tail tip (different from mammals)
   4. No subarachnoid space = no myelography

Question 10

Describe the ear anatomy of lizards. How many auditory ossicles do they have?

The iris of lizards is composed of what type of muscle?

Do lizards have a PLR?

What is unique about the lizard cornea?

Describe what you may find on your fundic examination of a lizard.

Answer 10

1. Special Senses
   
   1. Ear is covered in transparent skin (except for earless and horned lizards in which it is covered with a scale)
      
      1. Two auditory ossicles (mammals have three) = stapes and extra columella
      2. Inner ear = two sacs with a broad passage
      3. Utriculus = three semicircular canals arranged perpendicular to each other
      4. Eustachian tube connects the middle ear to the dorsolateral pharynx
   2. Iris = striated muscle
   3. Muscles of the ciliary body change the lens shape
   4. Consensual PLR is absent
   5. Cornea lacks a Descemet’s membrane
   6. Retina is avascular;
   7. Conus papillaris = large vascular body that protrudes into the vitreous
   8. Fovea centralis = depression in the retina that improves visual acuity (diurnal species)
   9. Parietal eye on dorsal midline in iguanas
      
      1. Connects neurologically ot the pineal body
      2. Regulates circadian rhythms

Question 11

What is unique about the tongue of chameleons?

How do their tongues function?

Answer 11

• Tongues.
  
  • Chameleons – Over full body length, sticky fleshy tip for capturing prey.
    
    • Supported and propelled or retracted by specialized lingual muscles, the hyobranchial apparatus, and elastic collagen tissues.

Question 12

Describe the ideal housing set up for lizards (generally).

Answer 12

1. Housing Requirements
   
   1. Lizards need large cages for their active lifestyle
      
      1. Horizontal dimensions are more important than vertical height for terrestrial species
   2. Cages may be made from glass, acrylic, timber, assorted plastics, fiberglass, and wire
   3. Caiman lizards require water to fully submerge in
   4. Do not use sand (obstruction) or redwood/cedar bark (oils damage respiratory system)
   5. Some species require vertical branches
   6. Require access to a thermal gradient within POTZ, also for light and humidity.
   7. Minimum acceptable size for enclosure varies, but bigger is better in most cases.
      
      1. Multiple comfortable resting spots, orientation of the cage should be appropriate for reflecting habitats of that spp.
      2. Important the lizard can choose appropriate temp, humidity, light exposure and feel safe and secure.
      3. Basking spots need to be secure enough for them to feel comfortable using them.
      4. Some lizards will choose thermal needs over exposure to UVB, artificial light and heat sources should be combined when possible.
2. Outdoor Enclosures
   
   1. Have a thermostat to regular heating sources and gradient
   2. Full spectrum UV light is important for vitamin D synthesis

Question 13

Describe the feeding strategies of lizards. Are there any specialists?

Describe the feeding of herbivorous lizards.

Describe the feeding of insectivorous lizards.

What are some common nutritional issues? How can those be addressed?

Answer 13

1. Feeding and Nutrition
   
   1. Carnivores, insectivores, herbivores, omnivores.
      
      1. Caiman lizard feed exclusively on snails in wild.
      2. Horned lizards exclusively ants and termites.
      3. Marine iguanas – marine vegetation.
   2. Feed herbivorous lizards dark, leafy greens
      
      1. Limit fruit and goitrogenic vegetables
   3. Feed insectivores crickets that have been gut-loaded for 4 days
      
      1. Apply supplements to prey regularly for young animals
   4. Chameleons may need to be hand fed
   5. Feeding fibrous insects and food can decrease incidence of periodontal disease in agamids
   6. Feed carnivores whole, dead prey
   7. Obesity is common. Also orthopedic disease, CV disease, GI and repro dysfunction appear releated to obesity.
   8. Limit caloric intake and maximize physical activity in captive animals.

Question 14

Describe surgery of the reproductive tract in lizards.

Describe the management of limb or tail amputations in lizards.

How shoudl abscesses be treated?

Answer 14

• Surgery (F8):
  
  • Surgery of the female repro tract often necessary to address problems ranging from preovulatory follicular stasis to egg-binding or dystocia.
  • Ovariectomy or ovariosalpingectomy is often performed as a preventive measure in captive lizards not intended for breeding.
  • Complete removal of all ovarian tissue is paramount.
    
    • If left behind, itsue may regenerate and ovulation may resume, resulting in peritonitis.
  • Amputations – Limbs or tail.
    
    • Tail – Important to know if spp is capable of autotomy.
      
      • If so, skin should be left open if tail regrowth is desired.
      • If no ta spp that is capable of autotomy, skin should be closed to expedite healing.
    • Lizards do well with limb amputations but avoid leaving stumps that could be traumatized.
      
      • Generally have to amputate at the coxofemoral or scapulohumeral joints.
  • Abscesses should be treated as surgical.
    
    • Removal of abscess and capsule is necessary.
    • Debride and treat topically if full excision not possible.
    • Cytology, histo, culture and sensitivity should be performed.

Question 15

Describe the two main approaches to lizard coeliotomy.

What are the concerns with the ventral abdominal vein?

Describe the closure

Answer 15

• Mader Ch. 98 – Lizard Celiotomy:
• Fasting recommended to minimize the size of GIT
• Two basic approaches to the coelom in lizards:
  
  • Ventral coeliotomy (midline and paramedian)
    
    • Preferred approach for most species
    • Most common
  • Lateral (flank) coeliotomy
    
    • Used primarily for laterally compressed lizards such as old-world chameleons
• Paramedian approach - incision parallel and lateral to midline then blunt dissect thin musculature
  
  • Allows to surgeon to avoid and identify ventral abdominal vein
• Midline celiotomy
  
  • Initial ventral midline skin incision then linea alba sharply dissected avoiding ventral abdominal vein
  • Main advantage - reduction in pain associated with an incision through the linea alba
• Ventral abdominal vein
  
  • Confluence of bilateral pelvic veins, joined bilaterally by hypogastric veins and single ventral pubic vein
  • Located along ventral midline, just axial to abdominal muscles
  • Distance from pubis to caudal origin of abdominal vein varies by species and patient size but approximately one-fourth distance between cranial pubic bone and umbilicus
  • Courses along inside of coelomic wall until reaching umbilicus, where it turns dorsad and joins the hepatic vein
  • Variable location within mesovasorum
    
    • Location at surgery depends on animal’s state of repletion and other space-occupying coelomic structures
  • Can be ligated if traumatized
• Region between cranial margin of pubis and extending one-fourth of distance toward umbilicus, and region cranial to umbilicus progressing to xiphoid à no significant ventral vessels present
• Fat bodies
  
  • Can be vascular and friable
• Small amount of “clear” free fluid not uncommon in healthy lizards
• Lateral (flank) celiotomy
  
  • Requires rib transection
  • Incision and subsequent scar not readily visible once healed
  • Complications after paramedian coeliotomy in chameleons are rare
  • Incision below lumbar spine in paralumbar space, often at an angle (caudal to or between the last ribs) to allow the largest possible incision without involving ribs
  • No major vessels on entry into the coelom
  • Technique also reduces interference by the paired coelomic fat bodies
  • Presence of air-sac–like extensions of lungs, which appear as clear finger-like projections often present in the surgical field in chameleons
• Closure of coelomic aponeurosis not considered a holding layer as in mammals
  
  • Seal only
  • Absorbable monofilament suture in 3.0 to 5.0 size depending on the patient size, in simple continuous pattern with minimal tension recommended
    
    • Exception - some gecko species (leopard geckos, African fat-tailed geckos, and crested geckos)
      
      • Skin delicate and fragile and does not have the same “holding” strength that more typical keratinized lizard skin does
      • Simple interrupted suture pattern recommended to close coelomic wall, followed by a typical horizontal mattress suture pattern in skin to increase strength and integrity of closure
  • Skin closed with nylon suture in horizontal mattress pattern to evert edges
    
    • Surgery and sutures placed too close to wound edges may accelerate ecdysis
    • Tissue adhesive over incision - help with waterproofing and protection

Question 16

Describe the presentation of nutritional secondary hyperparathyroidism in lizards.

Answer 16

Metabolic bone disease (fibrous osteodystrophy)

• Secondary nutritional or renal hyperparathyroidism
• Inappropriate exposure to UVB
• Stages
  
  • Preclinical
  • early clinical (anorexia, lethargy, difficulty ambulating, +/- tremors, neuro signs, hypocalcemia)
  • late clinical (thickened, swollen limbs, bowing - esp chameleons, pathologic fractures - often near metaphsysi, rubber jaw, neuro secondary to vertebral fractures)
• Pseudo hypertrophy of limbs from cartilage and fibrous tissue deposited on periosteal surfaces with progressive pressure atrophy of muscles

ZP

Question 17

Describe the effects of the following vitamin deficiencies or excesses in lizards:

Hypovitaminosis D

Hypervitaminiosis B

Hypovitaminosis A

Hypervitaminiosis A

Vit E/Selenium Deficiency

Vitamin B1 (Thiamine) Deficiency

Answer 17

Hypovitaminosis D - fibrous osteodystrophy

• Metastatic calcification (green iguanas), dystrophic mineralization (Uromastyx) with low D3

Hypervitaminosis B - Calcium salt deposition in arterial media, terminal nephritis (green iguanas)

Hypovitaminosis A - squamous metaplasia esp pharyngeal mucosa, conjunctiva, urogenital tract, upper and lower respiratory tract

• Organochlorine pesticides may inhibit vitamin A metabolism
• Old world chameleons - may predispose to stomatitis

Hypervitaminosis A - soft tissue mineralization (chameleons), segmental calcification in colon

Vit E/ Selenium deficiency - muscle degeneration and necrosis: cutaneous red-white discoloration, myocardial mineralization, granulomatous lesions in dermis

• Progressive inability to use tongue, circling, weakness (veild chameleons)

Vit B1 (thiamine) deficiency - severe brain lesions, CNS signs (tremors, abnormal axial skeleton posture, hyperextension, twisting)

ZP

Question 18

Describe the lesions associated with gout in lizards.

What affect does formalin have on urate crystals?

Answer 18

Gout - basophilic, needle-like (acicular), monosodium urate crystals (tophi) arranged in radiant pattern (or amorphous and eosinophlic to amphophilic), birefringent under polarizing light

• Deposited in and on tissues or in joints
• Predisposing factors: dehydration, renal disease
• Grossly chalk-like precipitates
• Articular - swollen and deformed joints, common in chronic
• Renal - white to gold foci grossly corresponding to tophi in renal tubules on histo
  
  • Results in renal tubular necrosis, secondary foreign body reaction, variably extensive fibrosis and nephromegaly in chronic cases
• Visceral
• *urate crystals solubilize in 10% buffered formalin, better preserved in 100% alcohol

ZP

Question 19

What are some common renal diseases of lizards, their lesions, and potential sequelae?

Answer 19

Renal disease - including degenerative changes with fibrosis, gout, and mineralization

• Most common outcome - nephromegaly esp green iguanas, may cause compression of distal colon and intestinal obstruction
• Renal secondary hyperparathyroidism - fibrous osteodystrophy
• Acute glomerulonephritis: thickening; membranous, exudative, and mesangioproliferative; intra- and extracapillary
• Chronic: fibrosis, glomerular tuft sclerosis, tubular nephrosis, brown pigment deposition in tubular epithelial cells, amyloid-like material in Komodo dragons

ZP

Question 20

Cardiac disease is over-represented in what species?

What diseases are commonly seen?

Answer 20

Cardiovascular disease

• Inland bearded dragons overrepresented
• Artherosclerosis, aortic aneurism, pseudoaneurism (large, fluctuant to firm swellings up to 5cm bulging at dorsolateral neck just caudal to skull)
• Hemopericardium

Question 21

What are two possible causes of avascular necrosis of the tail in lizards?

Answer 21

Trauma, venipuncture

ZP

Question 22

Describe the lesions and clinical signs of compressive myelopathy in lizards.

What species is commonly affected?

What site does this occur?

Answer 22

Compressive myelopathy - secondary to cervical spine subluxation in Komodo dragons (C1-C4)

• Articular cartilage degeneration, necrosis and axonal degeneration, multifocal hemorrhage, demyelination, diffuse Wallerian degeneration, oligodendrocyte necrosis

ZP

Question 23

Describe some of the common reproductive issues of female lizards.

What is the difference between follicular stasis and egg binding?

What lesions are present with egg-yolk coelomitis? Are any species particularly predisposed?

Answer 23

Folliculostasis, egg binding - environmental conditions

Obstructive dystocia

Yolk coelomitis - foreign body-type inflammation, mesothelial cell proliferation, secondary bacterial complication, often fatal

• Etiology trauma vs mature vitellogenic follicles failing to ovulate undergo atresia and rupture, released yolk overwhelms resorptin capacity
• Major cause of death in captive sexually mature female Fiji Island banded iguanas

Question 24

What are some causes of cloacal prolapse in lizards?

What about hemipenal prolapse?

Answer 24

Cloacal and penile prolapse - nutritional, renal secondary hyperparathyroidsm, infection, dystocia, urolithiasis, neoplasia

• Causes of hemipene prolapse: truama, traction during copulation, myopathy, neurologic disease, GI foreign body

Question 25

Describe the potential etiologies and sequelae of proliferative spinal osteopathy in lizards.

What about sponyloarthorpathy?

What about spinal mycoplasma infections?

Answer 25

Proliferative spinal osteopathy - unknown etiology, more frequent in snakes, variably lytic and proliferative lesions along vertebral column

• Proposed etiologies: trauma, infectious disease, nutritional deficiency, neoplasia, immune-mediated disease, reduced physical exercise in captivity, vertebral instability, djd, neoplasia
• Sequelae: remodeling, reduced or lost mobility, kyphosis, lordosis, and/or scoliosis (combo of all 3 called rhoecosis)

Spondyloarthropathy - major nontraumatic osseous pathology in lizards, varanids overrepresented.

• Salmonella and Shigella linked in primates but no correlation in lizards
• Mycoplasma iguana* sp. Nov - documented in vertebrae of green iguanas with granulomatous osteomyelitis and hindlimb paralysis, meningitis, and demyelination of spinal cord

Question 26

What are some of the most commonly encountered organisms causing bacterial disease in lizards?

What organism is carried by bearded dragons but causes fatal dermatitis and septicemia in uromastyx species?

Answer 26

• Bacterial
  
  • Most gram-negatives.
  • Ideally base abx on culture and sensitivity.
  • Commonly encountered organisms – Pseudomonas, Klebsiella, Aeromonas, Proteus, Salmonella.
  • Anaerobics – Clostridium, Bacteriodes, Fusobacterium.
  • Devriesea agamarum – Dermatitis and septicemia in Uromastyx, but bearded dragons are asymptomatic carriers.

Question 27

Adenoviruses are what kind of viruses?

What genus is most commonly seen in lizards?

What about bearded dragons specifically?

What clinical signs are present

What lesions are found on necropsy?

What do the inclusion bodies look like?

Are there any specific species specific lesions?

What coinfections commonly occur?

Answer 27

Adenovirus (Family Adenoviridae) - large, nonenveloped, double-stranded DNA virus

• Genus Aviadenovirus most commonly documented in lizards
• Other: Mastadenovirus, Atadenovirus, Ichtadenovirus, Siadenovirus, new: Testadenovirus
• Bearded dragons - Agamid adenovirus 1 in EU and US
• CS: none to wasting, anorexia, CNS (circling, head tilt)
  
  • Unremarkable on gross, histo: prominent basophilic intranuclear inclusions mostly in hepatocytes - hallmark, necrotizing and/or proliferative (liver, heart, kidney, pancreas, intestine, bile duct)
  • Proliferative trachea and esophageal mucosa (Jackson’s chameleon)
  • Coinfection with dependoparvoviruses, ranavirus, invert iridovirus, coccida, nematodes

Question 28

What type of viruses are iridoviruses?

What two iridoviruses affect lizards?

What are their classic histological findings?

What do the inclusion bodies look like?

Answer 28

Iridoviruses (family Iridoviridae) - large, enveloped or nonenveloped, double stranded DNA

• Genera: Iridovirus, Chloriridovirus, Ranavirus, Megalocytovirus, Lymphocystisvirus
• Ranavirus - OIE reportable in amphibians (not reptiles)
  
  • Hallmark: intracytoplasmic basophilic inclusions associated with necrosis, commonly affect skin (necrotizing, ulcerative, hyperkeratotic dermatitis)
  • Ddx husbandry, Nannizziopsis sp., secondary Gram neg bacteria, Dermatophilus, invert iridovirus, parasites, trauma
  • Other possible findings: myositis, osteomyelitis, hemorrhages and edema of GI, granulomatous dermatitis, sinusitis, vacuolar tubulonephrosis, hyperemia and hemorrhage and necrosis in liver
• Invert Iridoviruses (Iridovirus, Chloriridovirus) - isolated from beardies with pneumonia, frill-necked lizard with pox lesions, spiny-tailed lizard with hyperkeratosis, chameleon, green iguana
• Intraerythrocytic iridoviruses: unclassified iridoviruses (proposed genus Hemocytivirus)
  
  • Originally misidentified as intraerythrocytic parasites (Pirhemoctyozoon, Toddia) - reptile erythrocytic virus
  • Reported in several species, inconsistent/nonspecific clinical signs (anorexia, blepharospasm, white plaques on dorsal tongue, pale mm, weight loss)
  • Histo: intracytoplasmic inclusions in up to 40-50% of mature and immature RBCs
  • Disease occurrence appears to be temp dependent

Question 29

What type of viruses are herpesviruses?

What are the classic lesions associated with herpes in lizards?

What are the inclusion bodies like?

What are the clinical signs and lesions associated with the following herpesviruses in lizards?

Iguanid Herpesvirus 1

Iguanid Herpesvirus 2

Varanid Herpesvirus 3

Varanid Herpesvirus 1

Answer 29

Herpesviruses (family Herpesviridae, subfamily Alphaherpesvirinae) - large, enveloped, double stranded DNA viruses

• Skin, oral cavity, visceral organ lesions, especially iguanas
• Hallmark - intranuclear eosinophilic inclusions associated with necrotizing and/or proliferative lesions
• Herpesvirus-associated papillomas: cluster around base of head in male European green lizards, caudal dorsum near tail base in females
  
  • Histo: epithelial hyperplasia with intralesional enlarged nuclei with marginalization of chromatin and intranuclear inclusions
• Iguanid herpesvirus 1 - first herpesvirus isolated but no lesions in that individual
• Vs another male green iguana that died 5d after moving to cooler room with liver necrosis and intralesional intranuclear eosinophilic inclusions
• Uncharacterized herpesvirus was associated with multisystemic granulomatous inflammation in iguanas
• Iguanid herpesvirus 2 - hepatic and splenic necrosis with intranuclear eosinophilic inclusions and mononuclear interstitial myocarditis and myositis in San Esteban Chuckwalla
• Varanid herpesvirus 3 - in monitor lizards with hepatitis and enteritis with coagulative necrosis and intralesional intranuclear eosinophilic inclusions
• Gerrhosaurus herpesvirus 1-3 - recurrent stomatitis and cheilitis in plated lizards
• Varanid herpesvirus 1-associated SCC in green tree monitors, proliferative stomatitis, gingivitis
• Helodermatid herpesvirus 1 - odontogenic tumor in banded Gila monster

Question 30

What types of viruses are paramyxoviruses?

What paramyxoviruses affect lizards?

What clinical signs and lesions are typically observed?

What are the inclusion bodies?

Answer 30

Paramyxoviruses (family Paramyxoviridae) - enveloped, single stranded, negative sense RNA

• Genus Ferlavirus, genotypes A, B, C, and distinct Tortoise lineage
• Rarely associated with disease in lizards - only report is Caiman lizards and a water dragon
  
  • Found dead or observed anorexic before death
  • Gross: yellow/gray mucoid fluid and yellow flocculent material in central airway of lungs
  • Histo: proliferative heterophilic and histiocytic interstitial pneumonia, diffuse, marked hyperplasia and hypertrophy of respiratory epithelial cells lining faveoli (type II pneumocytes) with syncytial cells, occasional intracytoplasmic 1-2 um eosinophilic inclusions in epithelial cells

Question 31

How does Salmonella affect lizards?

What groups of lizards arre more likely to develop disease?

Answer 31

Salmonella - normal flora

• Systemic salmonellosis with disease often in debilitated animals with concurrent infections, overall lower prevalence of disease in lizards than other taxa
• Lesions: skeletal, skin, visceral, joints, periarticular
• Ovarian granulomas, salpingitis, dermatitis, diphtheritic enteritis, purulent osteomyelitis, arthritis, periarticular abscess with subcu involvement
• Recent study - risk of developing disease was higher in carnivorous species

Question 32

What species of lizards are most susceptible to Devrisea agamarum?

What is the carrier?

What clinical signs are associated with this disease?

Answer 32

Devriesea agamarum - Gram + bacillus

• Oral microbiota of bearded dragon, may be associated with disease
• Uromastyx particularly susceptible, agama, collared lizards, bearded dragon reservoir
• Proliferative and hyperkeratotic dermatitis, cheilitis with crusty brown skin, septicemia, limb swelling
• Water dragons and basilisk: multifocal granulomas, panniculitis, hepatitis, pneumonia, osteitis, myositis, skin wounds, subcu to coelomic fistulae
• Combine infection with Nannizziopsis reported in inland bearded dragon

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Question 33

What are the clinical signs associated with Dermatophilosis in bearded dragons?

How is this organism identified cytologically?

Are there any associations with other infections?

Answer 33

Dermatophilus - Gram positive cocci, ZOONOTIC potential

• Unique characteristic growth resembling railroad tracks - cocci arranged in parallel serpiginous lines
• Hyperkeratotic dermatitis - characteristic lesion, subcu nodules
• Recent outbreak in bearded dragons associated with ranavirus - Dermatophilu chelonae, now Austwickia chelonae
  
  • Multifocal to coalescing 1-10 mm crusty nodular lesions over ventral aspect of body, head, tail, and limbs
  • Ulcerative and necrotizing with epidermal hyperplasia, parakeratosis, granulation tissue, intralesional G+ cocci

Question 34

What Mycobacterium species commonly affect repriltes?

What lesions on gross and histo are typically observed?

What is the preferred diagnostic?

Answer 34

Mycobacteria - acid-fast positive bacilli

• Mycobacterium tuberculosis complex
• Nontuberculous Mycobacterium - most mycobacterium isolated from reptiles (Runyon groups I and IV)
• Most common reported in reptiles is M. marinum but recent reports say M fortuitum and M fortuitum-like bacteria most common
• Chronic disease, lesions range from extracellular proliferation of Mycobacterium spp. With necrosis and heterophilic to histiocytic inflammation (early) to classic granuloma formation (chronic)
• Systemic with mycobacterial myocarditis reported in frilled lizard, granulomatous osteomyelitis from atypical mycobacteriosis in barded dragon report
• PCR more sensitive than histo and IHC

Question 35

What Chlamydial organisms have been documented in lizards?

What lesions are seen?

Answer 35

Chlamydia pneumoniae

• Concurrent infection with poxvirus in flap-necked chameleon
• C pneumonia and C felis in farmed green iguanas with diffuse intestinal mucosa necrosis
• Chlamydia like organisms in lizards with granulomatous lesions

Question 36

What are the typical lesions associated with Nannizziopsis infections in lizards?

What is the most common species and which lizard species does it affect?

What species are affected by the following pathogens?

N. dermatitidis

N barbata

N chlamydospora

N plurispetata

N arthrospoides

Answer 36

Chrysosporium anamorph of Nannizziopsis vriesii-complex (CANV-complex) - order Onygenales

• Primary pathogen in lizards, present on skin of clinically healthy reptiles <1% of time
• At least one fungi in CANV-complex has fulfilled Koch’s postulates in veiled chameleons
• Bullae or small cutaneous vesicles (early stages), rupture to form serocellular crusts and hyperpigmentation. Epidermal hyperplasia with hyperkeratosis and necrosis, sloughing of skin to expose underlying dermis. Granulomatous and nodular dermatitis, cellulitis, myositis, deep granulomas in visceral organs and intralesional fungal hyphae.
• Granulomatous inflammation prominent in bearded dragons, conjunctivitis and rhinitis less commonly described
• Histo: fungi 2-4 um diameter, hyaline, mostly parallel walled, septate hyphae with irregular branching and arthroconidia
• Yellow fungus disease in bearded dragons - most commonly associated with Nannizziopsis guarroi - infections also identified in iguanas, agamas, giant girdled lizards
• Nannizziopsis dermatitidis - day geckos and chameleons
• Nannizziopsis barbata - coastal bearded dragons
• N chlamydospora, N draconian - inland bearded dragons with typical YFD lesions
• N plurispetata- southeastern five-lined skink
• N arthrosporioides - captive water dragon

Question 37

What dermatophytes affect lizards?

What are the observed lesions?

Answer 37

Dermatophytosis

• Systemic Microsporum canis in green iguana, nodular dark pigmented skin lesion, multiple granulomas in liver, lung, cardiac apex
• Trichophyton mentagrophytes var. Interdigitale - green iguanas with patchy darkened skin, on histo - acanthotic, hyperkeratotic, with intralesional fungal hyphae.
  
  • Tenerife lizard with ulcerative and heterophilic pustular dermatitis
  • Trichosporon cutaneum - nucal hematomas in green anole
  • Chamaleomyces sp. (ascomycete) - systemic and fatal infection in chameleons
  • C granulomatis, C viridis with dermatitis and granulomatous lesions in tongue and throat of veiled, panther, and carpet chameleons

Question 38

What are the clinical signs associated with microsporidiosis in lizards?

How are these identified histologically?

What is the primary species affecting bearded dragons?

Answer 38

Microsporidiosis - 2-3 um Gram and acid-fast positive with PAS positive small polar granule

• Bearded dragons - death without clinical signs
• Granulomatous inflammation with intrahistiocytic organisms causing expansion of colonic wall and in adrenals and ovaries
• Intracytoplasmic and extracellular organisms in hepatocytes with liver necrosis, renal epithelial cells with cytoplasmic vacuolation, pulmonary and gastric mucosal epithelium, enterocytes, capillary endothelial cells, and ventricular ependymal cells in the brain

Encephalitozoon - multisystemic granulomatous inflammation in inland bearded dragons

• Strong sequence similarity but was distinct from E. cuniculi
• Microsporidiosis due to Encephalitozoon sp. Reported in an African skink, common wall lizard (E lacerate), and tuatara (Pleistophora sp.)

Question 39

What are the clinical signs associated with Entamoeba invadens infection in lizards?

What lesions are observed?

What species are affected?

Answer 39

Amoeba

• Entamoeba invadens (presumed) - intestinal and liver disease, insignificant to fatal
  
  • most common in monitor lizards - hemorrhagic colitis, enteritis, and hepatitis or multisystemic infection with ulcerated skin wounds and granulomatous myositis
• Also reported in blue-tongued skinks, green iguanas with systemic disease

Question 40

What are the clinical signs of Cryptosporidium in lizards?

What species are overrepresented?

What lesions are found?

Any unique presentations of cryptosporidiosis in lizards?

Answer 40

Cryptosporidium sp

• C. varanii (syn. C. saurophilum) in lizards (C serpentis - snakes) - proliferative gastritis in snakes, and intestinal tract in lizards
• Geckos over represented - leopard geckos: anorexia, lethargy, diarrhea
  
  • Gross: marked reduction of fat deposits, thickening and reddening of intestinal wall - mucosal hyperplasia and mononuclear cell infiltration in small intestine
• Green iguanas - cystitis and colitis, recurrent cloacal prolapse
• Gastric crypto with mucosal hyperplasia - free-ranging frilled lizard, chameleon, ocellated lizards, savannah monitor
• Aural polyps with protrusion of typanic membranes in green iguanas
• Renal cryptosporidiosis – green iguana and Parson’s chameleon
• Cryptosporidial sialoadenitis – green iguana

Question 41

What are the two primary coccidial parasites of bearded dragons?

What are the signs and lesions associated with these diseases?

Answer 41

Isospora amphiboluri - bearded dragons, mortality in neonatal and juvenile

• Begins in duodenum, progresses to colon
• Co-infection with adenovirus and dependoparvovirus reported

Eimeria pogonae - new coccidian (genus Choleoeimeria), biliary and gallbladder epithelium in bearded dragons

• Oocysts in intestinal contents and biliary epithelium - aggregated in clusters
• Develop in epithelium of gallbladder and bile ducts
• Gross: markedly dilated gall bladder with focal thickening and tan discoloration of wall
• Histo: epithelia metaplasia, hypertrophy, cell degeneration with numerous heterophils in subepithelial tissue

Question 42

What is the most common mite affecting lizards?

Answer 42

Mites - 6th most common lizard skin disease

• Ophyonissus sp. (Macronissidae) - most common genus of mites in lizards
• O. natricis – most common species in snakes and lizards
  
  • Severe infestations can lead to anemia

Question 43

What are the three most common tick types affecting lizards?

Answer 43

Ticks

• Amblyomma – especially varanids, iguanids, teiids
  
  • some species specific
• Aponomma – also common in reptiles
• Argasid ticks also reported in lizards

Question 44

What are the species of crypto that affect lizards?

What is the clinical presentation of these animals?

How is it diagnosed?

Answer 44

Mader Ch 155 Lizard Cryptosporidiosis

• Definition:
  
  • Cryptosporidium – protozoal parasites.
    
    • Suborder eimeriorina.
    • C. varanii aka C. saurophilum in lizards.
      
      • Intestinal predilection (small intestinal mucosa).
      • Has also been found less commonly in gastric mucosa, LI, cloaca.
• Clinical significance and known etiology:
  
  • Many subclinical, can lead to clinical disease (if so, highly debilitating).
• Clinical presentation and diagnostic confirmation:
  
  • Asymptomatic cases – oocysts often detected during fecal screening.
  • Clinical cases – chronic enteritis, with wasting in geckos.
  • PE – loss of muscle mass, reduced appetite, anorexia, lethargy, weakness, diarrhea, fecal staining around cloaca.
    
    • Cloacal prolapse, cystitis reported in green iguana.
  • Dx – ID oocysts from feces after modified Ziehl-Neelsen stain.
    
    • Immunofluorescence antibody tests (IFAT) on fecal.
      
      • But oocyst must be shed at time of testing.
      • Crypto is intermittently shed, repeat testing for both techniques required to avoid false negative.
    • Definitive dx requires intestinal biopsy.
  • Carnivorous lizards – oocysts may be incidental (ingested in prey).
    
    • Nonpathogenic – C. muris, C. parvum.
    • Confirm with PCR, correctly ID spp.

Question 45

Describe the treatment of cryptosporidiosis in lizards?

How is this disease best prevented?

Answer 45

• Preferred tx:
  
  • No singular agent proven efficacious.
  • Crypto is not self-limiting, and chronic shedding occurs.
    
    • Found to be reduced after tx with paromomycin.
    • Tx effective in green iguanas with halofuginone or a combo of TMS or spiramycin and metronidazole along with hyperimmune bovine colostrum.
• Px and prevention:
  
  • Transmitted fecal-oral.
    
    • By direct contact with lizards or fomites.
    • Ingestion of sporulated oocytes can lead to infection.
    • Environmental stress, high stocking density esp of young animals.
    • Quarantine 3 mos and repeat fecals recommended.
    • Environmental hygiene.
      
      • Physical removal of feces and contaminated substrate.
      • Surfactants can aid in removal of organic material on solid surfaces.
        
        • Ammonia (5%), formalin (10%) with contact time of 18h at 4 deg C.
        • Moist heat (45-60 deg C for 5-9min), freezing, or desiccation appears to be most effective ways to clear environment after thorough cleaning.
    • Zoonotic potential is low due to host-specific nature of parasite.

Question 46

Describe the ideal radiographic imaging of lizards.

Answer 46

Ideal study

• DV vertical beam and lateral horizontal beam images
• Lizard as close to cassette or detector as possible
• For evaluation of heart/lungs - extend limbs cranially
• For evaluation of head/neck - extend limbs caudally
• Coelom - extend pelvic limbs caudally
• Larger lizards respiratory evaluation - right and left lateral views recommended

Smaller body parts (oral cavity, extremity) - dental radiography

Fat bodies do not provide contrast, but can compress organs together more and worsen contrast

• Size useful in evaluating body condition

Osteoderms can obscure radiographic details

Question 47

Describe the imaging of the cardiovascular system in lizards.

What are some signs indicating cardiacc enlargement?

What is the most common cause of enlargement in lizards?

Answer 47

Cardiovascular system

• Cardiac silhouette in most cranioventral aspect of coelom in most lizards (more caudally in monitors)
• Tape pectoral limbs forward for better visualization of heart and greater vessels on hb lateral - apex, base, and cranial margin may still be poorly visualized (summation)
• Cardiac borders are not normally discrete - not surrounded by aerated lungs
• Cardiac size evaluation - relationship of trachea and lungs, width of silhouette typically increases with enlargement, more soft tissue filling in cranioventral coelom, increased discernibility of margins due to greater effacement with lungs
• Most common causes of cardiac enlargement in lizards: pericardial effusion, structural heart disease -> echo recommended

Question 48

Describe the imaging of the respiratory system in lizards.

What are some differentials for soft tissue consolidations?

What does pneumonia look like? Is it common?

Answer 48

Respiratory system

• Anesthesia and positive pressure ventilation recommended to allow best view with inflated lungs - however overinflation can be misinterpreted as response to therapy
• Larger air spaces than mammals - more radiolucent, which should be uniform other than vasculature
• Advanced lizards (skinks) - more faveolar parenchyma in addition to chambered lungs
• R and L lateral horizontal beams recommended if patient exceeds 6 cm in width
• DV also helpful (unilateral lung hyperinflation in a New Caledonian giant gecko from pulmonary-tracheobronchial prolapse)
• Soft tissue consolidations - infectious (abscesses, granulomas) vs neoplasia -> indistinguishable on rads
• Pneumonia is uncommon - increased soft tissue opacity, sometimes fluid accumulations
• Dependent fluid can accumulate on HBL for distinctly marginated gas-fluid line
• CT is superior modality for respiratory evaluation of reptiles

Question 49

Describe the imaging of the GI tract in lizards.

What diseases are commonly diagnosed on radiography?

Describe the use of contrast studies.

Answer 49

Digestive system

• Best evaluated on DV
• Relatively short tract compared to mammals (carnivorous, insectivorous sp), but transit time is longer
• Large colons with fluid and/or gas in hindgut fermenters (green iguanas, chuckwallas)
• Lack of diaphragm - relationship of stomach and lungs dynamic
• Duodenum extends from pylorus in a caudal to cranial path between the stomach and cecum
• Empty GIT, liver, pancreas poorly visualized on rads (low soft tissue contrast)
  
  • Negative contrast coelomography (air introduction) reported but rarely used
  • Presence of gas or ingesta help (aerophagia common)
  • Fasting not important
  • Barium or iohexol helpful
• Diseases: obstruction, foreign body, gastroenteritis, constipation, hepatomegaly, hepatic masses, renomegaly
  
  • Rocks, sand, gravel in moderation is incidental but can lead to impaction
  • GI dilation - generalized (usually functional, enteritis) vs segmental ileus (mechanical, obstruction characterized by orad enlargement)
  • Obstructive pattern and foreign bodies are not always seen
  • Foreign body common in gastric lumen, intestines and cloaca
  • Mass effect more difficult to visualize than mammals - displacement of adjacent structures, abnormal gas foci, potentially obstructive pattern
• Barium: 25 mL/kg by oesophageal tube
  
  • Stomach should be distentended to initiate normal gastric reflexes
  • Evaluate motility or obstruction
  • Gastric masses - can use air to distend stomach as well as barium since high volume of contrast can mask foreign material
  • If issue is related to cloaca - instill contrast in cloaca
  • Normal appearance and transit times reported in green iguana, bearded dragon, and partially in common tegu
  • Large volumes of barium in distal git could cause constipation

Question 50

How do you differentiate between the stages of ovarian development in lizards?

What species have mineralized hemipenes?

Answer 50

Reproductive system - Figure 54.15 on p498 very helpful for repro stages in iguanas

• Follicular stasis more common in lizards than other reptiles
  
  • Normal developing ova: spericale soft tissue opacities in caudal coelom bilaterally (summate, overlapping, grape cluster)
  • Eggs may fill caudal coelom and displace intestines cranially
  • Abnormal eggs - abnormally large, irregularly shaped, inappropriate mineralization
• Sex ID - positive contrast in vent for presence/absence of hemipenes
• Monitor lizards have mineralized hemipenes; no contrast needed
• Ovarian teratoma, ovarian torsion - soft tissue masses/mass effect identified
• Multimodal approach (ultrasound) recommended

Question 51

Why is imaging of lizard kidneys difficult?

How can you detect renal enlargement?

What methods are available to enhance imaging?

Answer 51

Urinary system

• Most lizard kidneys in dorsocaudal coelom - green iguana kidneys difficult to visualize in pelvis
  
  • If kidneys protrude from pelvis in green iguana, suggests renal enlargement -> can compress colon as well
• Mineralization makes identification easy
• Enhance visibility with negative contrast cloacographpy or excretory urography
• Urinary bladder calculi - potassium or calcium salts complex with uric acid
  
  • Dietary issues (excessive protein, dehydration)
  • Urine retention
  • Bacterial infection
  • Irregularly marginated or rounded
  • Can be more cranial than you would expect
• Cloacal calculi occasionally seen
• Nonionic ionated contrast preferred, avoid putting barium in ureters or kidneys; infuse with air as well

Question 52

Describe the imaging of the musculoskeletal system in lizards.

What radiographic findings are consistent with metabolic bone disease?

Following a fracture, when should radiographs be performed to confirm healing?

What other differences in bone healing occur in lizards compared to mammals?

Answer 52

Musculoskeletal system

• Common tool to evaluate nutritional secondary hyperparathyroidism, trauma, infection, and neoplasia
• Normal radiographic appearance of this system in green iguana, bearded dragon, common tegu, and leopard gecko have been reported
• Decreased mineral opacity - poor diet/lighting, renal secondary hyperparathyroidism (less common)
  
  • Most obvious in long bones in corticomedullary region
  • Soft tissue enlargement associated with fibrous proliferation
  • Thinned cortices
  • Long bone bowing
  • Pathologic fractures
  • With treatment - will see an increase in bone opacity and cortical thickness, but bones have decreased trabecular pattern and indistinct cortical borders
• Over supplementation of D3/Calcium or renal disease can cause soft tissue mineralization
• Digital luxations commonly missed on PE
• Fractures with stabilization - immediate post operative rads are essential for baseline
• Bone healing - mixed fibrous and mineralized callus, precedes radiographic healing
• Osteomyelitis is common complication - recheck rads 2-6 weeks after surgery recommended
• To assess healing - recheck rads 8-16 weeks post injury/repair- mineralized callous and fibrous callous, twice as long as mammals
• Radiographic confirmation of healing - may be more than 6 months
• Lucent areas may be seen in completely healed fracture, unlike mammals
• Lizards have exuberant periosteal response with trauma or infection - vertebra/ribs
  
  • Spinal rigidity
  • Vertebral hyperostosis may secondarily occlude blood vessels -> can lead to tail necrosis
• Skull infections - progressive cortical and medullary bone lysis (osteomyelitis), teeth lost frequently
• Osteomyelitis can have persistent lucent defects - clinical correlation with healing is essential
• Lucency can be non ossified fibrous tissue
• Septic arthritis - lytic process with lysis of subchondral bone plate with extension into epiphysis

Question 53

List several differentials for the following musculoskeletal signs in lizards:

Lameness

Skeletal/Spinal Deformities

Tail Autonomy

Avascular Necrosis of the Tail

Swelling at Ventral Tail Base

Answer 53

• Musculoskeletal signs
  
  • Lameness and Skeletal and Spinal Abnormalities
    
    • MBD – most common
      
      • Fibrous osteodystrophy, osteomalacia, osteoporosis, osteopetrosis, pathologic fractures
    • Fractures
    • Soft tissue injury
    • Joint abnormalities
      
      • Articular gout, periarticular gout, pseudogout
        
        • Gout = UA deposits in joint
        • Pseudogout = any crystal other than sodium urate in joint
    • Ossifying spondylosis
      
      • Related to age, osteomyelitis, or metabolic abnormalities
      • Spine and tail stiff and unyielding resulting in altered gait
    • Hypertrophic osteopathy with periosteal proliferation of long bones related to coelomic space-occupying masses – green iguana case report
  • Tail
    
    • Tail autonomy
      
      • Most iguanid lizards as well as many skinks, geckos, and anguid lizards
        
        • Not in agamid lizards, monitors, or true chameleons
      • Fracture planes
        
        • Caudal vertebra has cartilaginous fracture plane through vertebral body and neural arch
        • Absent in cranial part of tail
        • Iguanas - replaced by bone as lizard grows, tail breaks off less easily in adults
        • Crested gecko - tail autotomy but does not regenerate tail after
    • Avascular necrosis of the tail
      
      • Common in green iguanas and central or inland bearded dragons
      • Caused by trauma, hematogenous-borne infection, osteomyelitis of caudal vertebrae, or iatrogenic damage
    • Swelling at the ventral tail base
      
      • Seminal plugs in hemipenes
        
        • Often bilateral and symmetric
      • Green iguanas and chameleons undergo dramatic enlargement of hemipenes with sexual maturity
      • Blue-tongue lizards – can develop hemipenal sac abscessation
  • Deformities
    
    • Kyphosis and scoliosis - genetic defects, malnutrition, and pathology of the epaxial muscles

Question 54

List differentials for the following dermatological clinical signs in lizards:

Yellow crusting and ulceration of the skin

Dysecdysis

SC Swellings on lateral and ventrolateral neck (particularly in geckos)

SC Swellings

What is the SC worm that affects chaemeleons?

Answer 54

• Dermatological signs
  
  • Nannizziopsis guarroi à “yellow fungus disease”
    
    • primarily affects bearded dragons but has been reported in multiple other lizards, including veiled chameleons and green iguanas
    • severe crusting and ulceration of skin, particularly around head
• Dysecdysis
  
  • Lizards shed in pieces
    
    • Geckos - skin comes off in one piece
  • Most common cause - lack of humidity
  • Associated with iatrogenic hypovitaminosis A in chameleons and leopard geckos
• Abscesses
  
  • Encapsulated, inspissated pockets of caseous debris
• Endolymphatic sacs aka calcium or chalk sacs
  
  • Day geckos, crested geckos, gargoyle geckos
  • Bilaterally symmetrical subcutaneous swellings on the lateral and ventrolateral neck
    
    • Gargoyle geckos - dorsally in oral cavity
  • Function to store calcium
  • Radiopaque on radiographs
  • Larger in geckos that have been heavily supplemented with calcium and vitamin D
  • Larger in females
• Sebaceous or keratinaceous cysts
  
  • Primarily in tails of green iguanas and multiple locations on bearded dragons
  • Resemble dry abscesses with a solid core of epidermal debris
• Subcutaneous nematodes and filarid parasites
  
  • Subcutaneous masses
  • Common in chameleons - Foleyella spp
• Pseudoaneurysm or dissecting aneurysm
  
  • Observed in the dorsolateral cervical region of captive bearded dragons
  • Blood on aspiration
  • Immediately refills
  • Blood coagulates in chronic cases

Question 55

Provide some differentials for the following GI signs

Stomatitis

Exposure gingivitis

Pharyngeal edema

Flacid paralysis of the tongue

Vomiting & Regurgitation

Diarrhea

Cloacal Prolapse

Answer 55

• Gastrointestinal signs
  
  • Stomatitis
    
    • More common in snakes and chelonians than lizards
    • Usually the result of poor husbandry conditions, including suboptimal temperatures, malnutrition, and overcrowding
    • Herpesvirus - proliferative stomatitis in green tree monitors
    • Occurs secondary to other conditions such as pneumonia and septicemia
    • Signs - inflammation, ulceration, abscessation, and caseous deposits
  • Exposure gingivitis
    
    • Often mistaken for stomatitis
    • Common in MBD cases with deformed mandible causing gingival exposure
  • Chameleons - temporal glands dorsolateral to corners of mouth, sometimes become infected and distended with caseous debris
  • Pharyngeal edema – associated with renal disease in green iguanas and old-world chameleons
  • Flaccid paralysis of tongue in chameleons – hypocalcemia
  • Dental disease
    
    • Acrodont teeth - Agamidae and Chamaeleontidae
  • Vomiting and regurgitation
    
    • Lizards - more highly developed cardiac sphincter than snakes
      
      • Regurgitation only in very ill animals
  • agamid adenovirus infection in bearded dragons often associated with diarrhea
  • Parasites that can cause diarrhea - hookworms (Kalicephalus sp.), ascarids, strongyles (Rhabdias sp. and Strongyloides sp.), Entamoeba sp., coccidia (Eimeria and Isopora sp.), flagellates (Trichomonas sp., Monocercomonas sp., and others), and, less commonly, ciliates (Nyctotherus sp.)
  • Cloacal prolapse - cloaca itself vs bladder (when present) vs colon vs repro
    
    • Most common cause of a prolapsed cloaca in juvenile iguanas is poor muscle tone associated with hypocalcemia and spinal cord deficits from vertebral compression and fracture, usually a consequence of NSHP

Question 56

Provide smoe differentials for the following reproductive issues in lizards:

Still Births & Hatch Failure

Preovulatory Egg Retention

Answer 56

• Repro signs
  
  • Stillbirths and Hatch Failure
    
    • Improper environmental conditions for gravid female or complications with incubating eggs
      
      • Low or high environmental temperatures, low or high humidity levels, poor hygiene with mold or fungal contamination of the incubation media, and incubator failure
  • Preovulatory egg retention -undergoes vitellogenesis but does not ovulate
    
    • Enlarged ova remain on ovaries but fill coelomic cavity and cause anorexia
    • Some resorbed, others need ovariectomy

Question 57

What are the lungworms of lizards? What groups are most affected?

What are some differentials for nasal discharge?

Answer 57

• Respiratory signs
  
  • Common lungworms in lizards - helminths Entomelas spp. and Rhabdias spp.
    
    • Parasites most common in chameleons and monitors
  • Nasal discharge
    
    • Some lizards have sodium-secreting, potassium-secreting, and chloride-secreting nasal salt glands
    • Epistaxis and hemoptysis most commonly occur from metastatic mineralization in green iguanas

Question 58

What is the cause of arcus lipoides cornea in lizards?

What causes leopard geckos to develop plugs of caseous debris over their corneas?

What are some risk factors for cataract formation in lizards?

Answer 58

• Ocular signs
  
  • Pseudobuphthalmos – occluded nasolacrimal duct in animals with a spectacle
  • Exposure to excessively strong artificial ultraviolet light sources can cause blepharospasm and keratitis
  • Iatrogenic hypovitaminosis A
    
    • Common in chameleons and leopard geckos
    • Palpebral edema, squamous metaplasia, and photophobia
  • Iatrogenic avulsion of the spectacle
  • Leopard geckos can develop plug of caseous debris covering cornea
    
    • Causes - bacterial conjunctivitis, foreign objects, chronic hyperthermia from excessive use of heat sources, hypovitaminosis A
  • Arcus lipoides corneae - white band of material that may partially or completely surround cornea near limbus
    
    • Associated with aging
  • Cataracts
    
    • Juvenile cataracts – possibly genetic in monitors
    • Cataract after brumation - sometimes associated with damage from freezing

Question 59

What are differentials for convulsions, twitching, coma, ataxia or head tilts in lizards?

Answer 59

• Neurologic signs
  
  • Convulsions, Twitching, Coma, Ataxia, and Head Tilts
    
    • Adenovirus in juvenile bearded dragons
    • Hypocalcemia – nutritional or renal
    • Xanthomatosis (cholesterol clefts) with lesions in the brain resulting in neurological signs have been reported in geckos and water dragons
    • Septicemia and brain abscesses
    • Vitamin B complex deficiencies
      
      • Seen in carnivorous reptiles that are fed large amounts of frozen fish or in herbivorous lizards fed large amounts of frozen vegetables
      • Biotin deficiency - monitors fed raw eggs
        
        • Contain avidin - substance with antibiotic activity

Question 60

A recent study evaluated coelioscopy in bearded dragons.

What are some of the advantages of coelioscopy over coeliotomy?

Compare the ventral to left lateral approach in bearded dragons

Were there any complications associated with coelioscopy?

What organs were easily seen in both approaches?

What organs were better appreciated with the ventral approach?

Answer 60

Frei, S., Sanchez-Migallon Guzman, D., Kass, P. H., Giuffrida, M. A., & Mayhew, P. D. (2020). Evaluation of a ventral and a left lateral approach to coelioscopy in bearded dragons (Pogona vitticeps). American journal of veterinary research, 81(3), 267-275.

• Key Points:
  
  • Advantages to endoscopy – Direct visualization of internal structures by use of high-resolution imaging, allows collection of samples for cytologic, histologic, microbiological, and molecular testing. Minimally invasive vs exploratory coeliotomy.
    
    • Other studies in reptiles – Coelioscopy for liver and kidney bx in FW turtles and green iguanas, pulmonoscopy in ball pythons, cystoscopy for sex ID in FW turtles.
    • Coelioscopy in iguanas – Lateral approaches. No substantial difference between right or left lateral approaches in visibility of lungs, liver, pancreas, SI, LI, ovaries, oviducts, testes, epididymides, vasa deferentia, bladder, fat body, or kidney. For visual exam of heart, stomach, and spleen, left lateral preferred. For visualization of the gallbladder, right lateral is prefefrred.
  • Compared ventral approach (paramedian to avoid ventral abdominal and pelvic veins) to left lateral (9^th intercostal space) approach.
    
    • Pelvic veins converge into ventral abdominal vein just caudal to the umbilicus, avoided by incising to the left of the umbilicus.
  • Procedure well tolerated – 1 death on necropsy showed granulomatous nephritis and atypical cryptosporidiosis. Some CO2 accumulation in the SQ space during the lateral approach (difficulty getting through the coelomic membrane without a scalpel).
  • No obvious serosal divisions were evident.
  • Both – Visualization of heart, lungs, liver, stomach, SI, and fat body excellent for both sexes.
  • Ventral approach – performed more rapidly vs left lateral, better visualization of both lungs. Entire liver could be better evaluated. Gallbladder visualization much easier, especially in females. Easier to visualize the pancreas with this approach, especially in females. Adrenals hard to see in general but easier in males vs females.
  • Right kidney could not be visualized on left lateral approach

Takeaways: Celioscopy methods described here safe and effective for bearded dragons. Ventral approach better for visualization of right and left sided structures, gallbladder, pancreas, faster than lateral approach in general.

Question 61

A recent study evaluated the effects of UVB exposure on nocturnal leopard geckos.

What is the scientific name of the leopard gecko?

How did UVB exposure affect 25-hydroxyvitamin D3 levels?

Answer 61

Gould, A., Molitor, L., Rockwell, K., Watson, M., & Mitchell, M. A. (2018). Evaluating the physiologic effects of short duration ultraviolet B radiation exposure in leopard geckos (Eublepharis macularius). Journal of Herpetological Medicine and Surgery, 28(1-2), 34-39.

Abstract: Ultraviolet B radiation (UVB) is required by many vertebrates to stimulate the photobiochemical synthesis of vitamin D. Vitamin D plays many important roles in the body, including assisting in the absorption of calcium at the level of the intestines. Deficiencies in vitamin D can lead to the development of nutritional disease. Leopard geckos (Eublepharis macularius) are naturally nocturnal to crepuscular; therefore, it is not known whether they benefit from UVB radiation. The purpose of this study was to measure 25- hydroxyvitamin D3 concentrations in leopard geckos exposed to short duration UVB light. Twelve adult, male leopard geckos were used for this study. Blood samples were collected from the cranial vena cava to establish baseline 25-hydroxyvitamin D3 concentrations. Once the baseline samples were collected, the animals were randomly divided into two groups. The animals provided UVB radiation were exposed to non-UVB producing light for 12 h and UVB for 2 h, whereas animals in the control group only received non-UVB producing light for 12 h. Exposure to the UVB light occurred for 2 h per day: 1 h at 0600 h and 1 h at 1800 h to mimic dawn and dusk, respectively. An additional blood sample was collected 30 days after the initiation of UVB exposure. There was a significant difference (F ¼ 9.7, P ¼ 0.012) in 25-hydroxyvitamin D3 concentrations between the two groups, with UVB exposed geckos having significantly higher concentrations. The results of this study demonstrate that short duration exposure to UVB light can lead to increased circulating 25-hydroxyvitamin D3 concentrations in leopard geckos.

• UVB group - significantly higher 25-hydroxyvitamin D3 concentrations
• Leopard geckos exposed to short-duration (2 h) UVB capable of significantly increasing 25-hydroxyvitamin D3 concentrations over time compared with control not exposed to UVB but fed similar diet
• Crepuscular and nocturnal reptiles may have more sensitive and efficient mechanism for converting UVB to vitamin D

Question 62

A recent study evaluated the parasites of the blue iguana.

What is the scientific name of the blue iguana?

What protozoa were identified?

What helminths were identified?

What parasites were more likely to occur in captive individuals?

What parasites were more likely to occur in juveniles rather than adults?

Answer 62

Maurer, J. K., Burton, F. J., McClave, C. A., Kinsella, J., Wade, S., Cooley, J. M., & Calle, P. P. (2020). Parasites of the blue iguana (cyclura lewisi) from grand cayman island. Journal of Zoo and Wildlife Medicine, 50(4), 947-955.

Abstract: Feces (n = 226; 2004–2015) from healthy captive and wild blue iguanas (Cyclura lewisi) from Grand Cayman, Cayman Islands, were examined for endoparasites. Parasites identified included Nyctotherus sp. and Entamoeba sp. cysts and trophozoites, trichomonad trophozoites, and oxyurid and trichostrongylid eggs. Endoparasites from postmortem examinations (n = 13) included adult and larval nematodes: Ozolaimus megatyphlon, Ozolaimus monhystera, Alaeuris travassosi, Atractis mega, and an unidentified species of Oswaldocruzia. Entamoeba spp. were more likely in captive juveniles of both sexes than captive or wild adults of either sex; Entamoeba spp. were more likely in captive adult females than captive adult males; trichomonad trophozoites were more likely in adult captive and wild iguanas of both sexes than in captive juveniles of either sex; and Nyctotherus spp. were more likely in juvenile captive males than captive adult males or females and more likely in adult wild males than captive juvenile males. Trichostrongylid eggs were more likely in adult wild females than adult captive females and more likely in captive and wild adults of both sexes than in captive juveniles of both sexes. Oxyurid eggs were more likely in adult captive and wild iguanas of both sexes than captive juveniles of either sex. Blue iguanas have a variety of endoparasites regardless of age, sex, or captive vs wild status, with no type found exclusively in either captive or wild populations. Ectoparasites from wild adults included adult ticks (Amblyomma torrei) and a single adult mite (Hirstiella trombidiformis). All are new host records for this species and Grand Cayman. Knowledge of parasite status of captive and wild populations is important to evaluate the relative risk of introduction of captive animals into wild populations.

• Endangered spp, about 1000 wild individuals and wild population consists of captive-reared, captive-bred, or headstarted iguanas and offspring.
• Endoparasites:
  
  • Protozoa: Nyctotherus sp (ciliate), Entamoeba spp (amoeba), trichomonad flagellates.
  • Helminths: Oxyurids, trichostrongylids.
  • Adult and larval nematodes identified (five genera). Ozolaimus, Alaeuris, Oswaldocruzia, Atractis (viviparous, no eggs).
  • Entamoeba more likely in captive juveniles. Captive adult females > males.
  • Trichomonad trophozoites more likely in adult captive and wild iguanas vs juveniles.
  • Nyctotherus spp more likely in adult wild males.
  • Thrichostrongylids more likely in adult wild females. Adults > juveniles.
  • Oxyurids more likely in adults vs juveniles.
• Ectoparasites: Mite (Hirstiella spp aka Geckobiella trombidiformis lizard scale mite), tick A. torrei.

Takeaways: Most parasites more likely to occur in adults except for Entamoeba. Potential for multiple choice questions based on key points above.

Question 63

A recent study evaluated ketamine and medetomidine anesthesia for longer surgical procedures in the argentine tegu.

What is the scientific name of the argentine tegu?

What was unique about the doses used in this study?

How often did they need to supplement to maintain surgical anesthesia?

What was recovery time like?

Answer 63

Barrillot, B., Roux, J., Arthaud, S., Averty, L., Clair, A., Herrel, A., & Libourel, P. A. (2018). Intramuscular administration of ketamine-medetomidine assures stable anaesthesia needed for long-term surgery in the argentine tegu Salvator merianae. Journal of Zoo and Wildlife Medicine, 49(2), 291-296.

Abstract: To define a protocol of anesthesia for long-duration invasive surgery in a lizard, eight young adult Argentine tegus (Salvator merianae) of mean body weight 3.0 kg (interquartile range [IQR] 3.40–2.65) were anesthetized with a mixture of ketamine (K) and medetomidine (M) at 19°C, injected intramuscularly and equally distributed in the four limbs. As the experimental surgery procedure required a prolonged deep anesthesia with a good myorelaxation (between 16 and 21 hr), reinjections were required and reflexes were checked during surgery. Times for anesthetic induction, anesthetic reinjection, and recovery periods were recorded for five different combinations of ketamine-medetomidine: 1) 66 mg/kg K 100 μg/kg M; 2) 80 mg/kg K 100 μg/kg M; 3) 100 mg/kg K 130 μg/kg M; 4) 125 mg/kg K 200 μg/kg M; and 5) 150 mg/kg K 200 μg/kg M. The effect on the recovery speed of the postoperative atipamezole injection was also evaluated. The median induction time was 30 (IQR 35–27.5) min with no statistical difference between all the concentrations tested. The first reinjection of half a dose was administered after a mean of 5 hr (5.64 hr, IQR 5.95–4.84) as were the subsequent reinjections of a quarter dose (3.99 hr, IQR 5.98–3.23). Intramuscular administration of the ketamine-medetomidine combination is a simple, rapid, and efficient anesthesia for long-term surgery (>12 hr). A mix of 100 mg/kg ketamine and 200 μg/kg medetomidine, with reinjections every 4 hr of half a dose of the previous injection can maintain a good quality of anesthesia for at least 16 hr. The injection of atipamezole after the surgery reverses the effects of medetomidine and permits a reduction of the recovery period.

• Ketamine – Noncompetetive antagonist of NMDA receptor, plays important role in modulation of neurotransmission and neuron excitability.
  
  • Results in dissociative effect, affects the activity of the limbic system.
• Medetomidine – alpha 2 adrenergic agonist. Analgesic effect and myorelaxant properties, increases total anesthesia period. Blocks norepipherine release inducing profound sedation. Also inhibits interneurons in the SC for myorelaxation.
• Important to not wait longer than 5 hours for the subsequent dose to maintain plane of ax.
• Doses used in this study are much higher than were previously reported for anesthesia (i.e. ketamine 60 mg/kg; in this study used > 100 mg/kg).
• Recovery approximately 12 hours from injection

Takeaway: Ketamine and medetomidine protocol with reinjections every 4 hours of half doses of the previoius injection maintained good quality of anesthesia for up to 16 hours. Atipamezol reversed medetomidine without issues.

Question 64

A recend study evaluated the use of dexmedetomidine and midazolam with or without ketamine in several lizard species.

What were their main findings

Answer 64

Budden, L., Doss, G. A., Clyde, V. L., & Mans, C. (2018). Retrospective Evaluation of Sedation in 16 Lizard Species with Dexmedetomidine-Midazolam with or without Ketamine. Journal of Herpetological Medicine and Surgery, 28(1), 47-50.

Abstract: A retrospective review of sedation of lizards using dexmedetomidine-midazolam (DM) with or without ketamine administered intramuscularly or subcutaneously was performed. Forty-four sedation events, involving 25 individuals and 16 different species of lizards, were reviewed. Sedation was performed for physical examinations, imaging, biopsy collection, and wound treatments. Dexmedetomidine (median: 0.08 mg/kg, 25–75%: 0.05–0.1 mg/kg, range: 0.03–0.3 mg/kg) combined with midazolam (median: 1 mg/ kg, 25–75%: 0.85–1 mg/kg, range: 0.5–2 mg/kg) was used in 11/44 (25%) sedation events. In 33/44 (75%) sedation events, ketamine (median: 2.9 mg/kg, 25–75%: 2.43–3 mg/kg range: 0.9–5 mg/kg) was administered in addition to DM. Insufficient depth of sedation was reported for 2/44 (4.5%) events. Atipamezole (10 times the milligrams dose of dexmedetomidine) and flumazenil (median: 0.05 mg/kg, 25–75%: 0.05–0.05 mg/kg, range: 0.01–0.1 mg/kg) were administered for reversal of the sedative effects of DM in all sedation events. The most common complication noted was apnea, which occurred in 2/44 (4.5%) sedation events and resolved following administration of the reversal agents.

Key Points:

• Dexmedetomidine: alpha-2 agonist: sedation, analgesia, hypnotic, anxiolytic; adverse effects: dose dependent cardiovascular and respiratory depression
• Midazolam: anxiolytic: IM or SC in reptiles; minimal cardiovascular and respiratory effects
• Ketamine: NMDA antagonist; analgesia, dissociative; high doses à prolonged recovery times; low doses alone à inadequate muscle relaxation
• 22/44 events sedated via SC route; 19/44 events sedated via IM route; 2 not specified
  
  • 2/44 received hydromorphone in addition during the procedure
  • 4/44 received local lidocaine block
• Reversal: all reversed with atipamezole (median: 0.75mg/kg, 25-75%: 0.5-1mg/kg) and flumazenil
  
  • SC reversal 17/44; IM reversal 14/44
  • 6/44 required repeated reversal(s)
• Only 3 events had time to recovery reported (<20 min) after reversal administration
• No mortalities
• Previous literature
  
  • Doss 2017: leopard geckos dexmed 0.1mg/kg & midazolam 1mg/kg; atipamezole 1mg/kg & flumazenil 0.05mg/kg à loss of righting reflex with recovery in 6 +/-2 min
  • Arnett-Chinn 2016: reptiles midazolam IM à adequate sedation in 80% of events
  • Doss 2017: SC route in squamates (midazolam, dexmed, alfalxalone) à more rapid onset than IM

Take home: Dexmedetomidine, midazolam and ketamine provide adequate sedation/immobilization for a variety of squamate species requiring exams or small invasive procedures; ketamine provided deeper levels of sedation

Question 65

A recent study compared the use of alfaxalone and propofol in bearded dragons.

What did they find?

Which produced surgical anesthesia?

Which had better recoveries?

Was apnea seen in either group?

Answer 65

Perrin, K. L., & Bertelsen, M. F. (2017). Intravenous alfaxalone and propofol anesthesia in the bearded dragon (Pogona vitticeps). Journal of Herpetological Medicine and Surgery, 27(3-4), 123-126.

Abstract: Anesthesia is an essential part of veterinary care for reptiles; however, there is limited literature available for the anesthetic management of commonly kept species such as the bearded dragon (Pogona vitticeps). This study compares the intravenous use of 10 mg/kg propofol with 12 mg/kg alfaxalone. Both protocols resulted in smooth and rapid induction and subsequent intubation. A surgical plane of anesthesia, defined as a loss of reaction to noxious stimuli and absent muscle tone, was achieved in 5/8 (62.5%) alfaxalone animals and 0/8 of the propofol animals. Reflexes and muscle tone were regained from a cranial to caudal direction. There was no effect on the heart rate; however, both protocols resulted in respiratory depression, including 5 and 20 min durations of apnea in two of the alfaxalone animals. Differences in the characteristics of these two protocols are likely attributable to the different depths of anesthesia achieved. Further research is required to establish equipotent dosages to allow rigorous comparison. In conclusion, both agents at these dosages were effective and safe for inducing anesthesia and appeared to show dose dependent effects on respiration and duration of anesthesia.

Key points:

• Alfaxalone resulted in longer duration and greater proportion achieving surgical depth anesthesia (losing nociception) compared to propofol
  
  • Surgical plane anesthesia achieved in alfaxalone group (62%) and none in propofol group
  • Apnea only in alfaxalone group (2 animals required PPV)
  • Rough recoveries (muscle tremors, inability to right) in alfaxalone group (62%) and none in propofol group
• Both alfaxalone and propofol group
  
  • HR was unaffected by either agent
  • Muscle tone was regained in cranial to caudal direction with tail tone recovered around recovery time
• Depth likely dose dependent for both drugs, and 9mg/kg alfaxalone may be more suitable to compare to 10mg/kg propofol based on previous studies

Take home: Both alfaxalone and propofol effective and safe for induction of anesthesia. Alfaxalone associated with surgical depth of anesthesia, apnea, and rough recoveries.

Question 66

A recent study evaluated the effects of injection site on dexmedetomidine-ketamine sedation in leopard geckos.

Why does injection site matter?

Describe the flow of blood from the caudal half of reptiles to the vena cava.

How did injection site affect sedation?

Answer 66

Fink, D. M., Doss, G. A., Sladky, K. K., & Mans, C. (2018). Effect of injection site on dexmedetomidine-ketamine induced sedation in leopard geckos (Eublepharis macularius). Journal of the American Veterinary Medical Association, 253(9), 1146-1150.

OBJECTIVE To evaluate whether the sedative effects of a combination of dexmedetomidine and ketamine differed when it was administered IM in a hind limb versus a forelimb of leopard geckos (Eublepharis macularius).

DESIGN Randomized crossover study.

ANIMALS 9 healthy adult leopard geckos.

PROCEDURES Each gecko received a combination of dexmedetomidine (0.1 mg/kg [0.045 mg/lb]) and ketamine (10 mg/kg [4.5 mg/lb]; DK), IM, in a forelimb and hind limb in a randomized order and with a 7-day interval between treatments. All geckos received atipamezole (1 mg/kg [0.45 mg/lb], SC) 45 minutes after DK administration. Palpebral and righting reflexes, jaw tone, and superficial pain and escape responses were each assessed on a 3-point scale, and the scores for those variables were summed to calculate a sedation score. Those variables and heart and respiratory rates were evaluated at predetermined times before and for 1 hour after DK administration.

RESULTS For the forelimb treatment, mean sedation score was higher and mean heart rate was lower than the corresponding values for the hind limb treatment at most time points after DK administration. The righting reflex remained intact for all 9 geckos following the hind limb treatment but became absent in 7 geckos following the forelimb treatment.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of DK-induced sedation was greater when the combination was injected IM in a forelimb versus a hind limb of leopard geckos, likely owing to a hepatic first-pass effect following hind limb injection. In reptiles, IM hind limb administration of drugs that undergo hepatic metabolism and excretion is not recommended.

• Considerations for administration of drugs in hind
  
  • Renal portal system
    
    • Venous blood from tail, and to varying and minor degree from hind limbs, flows directly to kidneys
  • Chelonians, lizards, and crocodilians - venous blood from hind limbs flows into ventral abdominal veins, then directly into liver or hepatic portal vein
• Dexmedetomidine and ketamine both undergo hepatic metabolism
• 9 geckos received dexmedetomidine 0.1 mg/kg and ketamine 10 mg/kg IM in proximal left forelimb and left hind limb 7 days later
• Mean sedation score for the forelimb treatment was significantly (P < 0.01) greater than that for the hind limb treatment
• Forelimb treatment
  
  • More sedate, Sedate faster, Lower HR and RR

Takeaway: DK-induced sedation and cardiac depression in geckos was less when the drug combination was administered IM in a hind limb versus a forelimb. Hepatic first pass effect.

Question 67

A recent study evaluated the effects of oxygen supplemtnentation during anesthesia in bearded dragons.

What is the primary driver for reptile ventilation?

How does oxygen concentration affect recoveries?

Were any differences observed between 21% and 100% oxygen supplementation?

Answer 67

Ratliff, C., Parkinson, L. A., & Mans, C. (2019). Effects of the fraction of inspired oxygen on alfaxalone-sedated inland bearded dragons (Pogona vitticeps). American Journal of Veterinary Research, 80(2), 129-134.

ABSTRACT: OBJECTIVE To evaluate the effects of providing 100% O2, compared with provision of room air, in sedated spontaneously breathing inland bearded dragons (Pogona vitticeps). ANIMALS 8 adult bearded dragons. PROCEDURES Animals were sedated with alfaxalone (20 mg/kg, SC) and received 21% O2 (equivalent to room air) or 100% O2 via face mask (flow rate, 1 L/min) in a randomized, blinded, complete crossover study (2-week interval between treatments). Sedation variables, cardiopulmonary variables, venous blood gas values, and postsedation food intake were evaluated. RESULTS Respiratory rate, heart rate, oxygen saturation, and sedation quality were comparable between treatments. Venous blood gas analysis revealed a higher total Pco2 and HCO3 – concentration for the 21% O2 treatment. Post-sedation food intake was not affected by the inspired oxygen fraction provided during sedation. CONCLUSIONS AND CLINICAL RELEVANCE The fraction of inspired oxygen did not appear to have clinically relevant effects on physiologic variables of bearded dragons during and after sedation. Therefore, provision of 100% O2 can be considered for use in sedated bearded dragons without the risk of inducing hypoventilation. Similarly, failure to provide 100% O2 would be unlikely to result in clinically relevant consequences in healthy sedated bearded dragons.

• Reptile ventilation driven by BLOOD OXYGEN CONCENTRATION rather than CO2, so high oxygen tension environments can decrease spontaneous breathing
• Recent studies of monitors and beardies revealed no significant differences in time to return of spontaneous ventilation or recovery time when given 21% oxygen or 100% oxygen, though experience has shown that supplemental oxygen may result in depression of respiration
• Resp rate was not affected by FiO2, administration of 100% oxygen did not result in hypoventilation
• For both tx, resp rate decreased with time. HR was higher for the 21% O2 and spO2 lower but were not significantly different.
• In comparing baseline blood gas with 60min values in tx, bicarb, tCO2 and base excess significantly increased for 21% O2 at 60 mins
• No differences between treatments for time of food intake (ingestion of first crickets, eating all 5 crickets or total number of crickets). All ate 120min after recovery
• Only differences between 21% and 100% O2 were in blood gas values
• No significant differences in resp rate or pulse ox based on FiO2
• Contrast to results of prior study of intubated beardies which had a lower SpO2
• May be an unreliable method of measuring SpO2 and administration via ET tube may more fully pronounce discrepancy
• Blood gas results were venous and may not fully represent oxygenation
• Not providing 100% O2 did not result in significant hyperlactatemia
• Anecdotally advocated to allow reptiles to recover in room air for faster return to spontaneous breathing
  
  • Previous studies have indicated no significant differences in recovery and return of spontaneous ventilation with 100% O2 and 21% O2
• No effects on feeding behaviors noted 24-48hrs after sedation in either scenario

TAKE HOME: Supplementation of sedated beardies with 100% O2 did not have a negative effect on respiratory rate. Lack of oxygen supplementation did not have clinically important consequences

Question 68

A recent study compared alfaxalone and ketamine anesthesia in Haitian giant galliwasps.

What is the mechanism of alfaxalone? What complications are seen in reptiles?

What is the mechanism of ketamine? What are the complications seen with its use?

How did alfaxalone (15 mg/kg IM) compared with ketamine (40 mg/kg IM)?

Answer 68

Kleinschmidt, L. M., Hanley, C. S., Sahrmann, J. M., & Padilla, L. R. (2018). Randomized controlled trial comparing the effects of alfaxalone and ketamine hydrochloride in the Haitian giant galliwasp (Celestus warreni). Journal of Zoo and Wildlife Medicine, 49(2), 283-290.

Abstract: The immobilization properties and cardiopulmonary effects following intramuscular administration of one of two chemical immobilization agents were compared in the Haitian giant galliwasp (Celestus warreni) in a prospective, blinded, randomized controlled trial. Adult, clinically healthy galliwasps (n ¼ 30) were given a randomly assigned single intramuscular injection of either 15 mg/kg alfaxalone (n ¼ 15) or 40 mg/kg ketamine hydrochloride (n ¼ 15). Heart rate, respiratory rate, and depth classification stage were recorded every 5 min; cloacal temperature was recorded every 15 min to ensure maintenance within this species’ preferred optimal temperature range (75–858F, 24–298C). Physical examination, radiographs, and phlebotomy were performed in all animals. Alfaxalone given intramuscularly resulted in reliable anesthetic induction, maintenance, and recovery (total duration of anesthesia 57.7 6 23.6 min, recovery 7.9 6 7.8 min). Ketamine hydrochloride resulted in variable levels of sedation or anesthesia and a longer recovery (total duration of anesthesia 14 617.5 min, recovery 47.9 6 19.3 min). Heart and respiratory rates remained within clinically acceptable ranges in all lizards using both protocols; however, alfaxalone animals had lower heart rates and respiratory rates associated with increased anesthetic depth as compared to ketamine hydrochloride animals (heart rates: alfaxalone 59.6 6 13.3 beats/min, ketamine hydrochloride 71.9 6 7.9 beats/min; respiratory rates: alfaxalone 33.4 6 16.8 breaths/min, ketamine hydrochloride 50.0 6 16.2 breaths/min). Duration of anesthesia for alfaxalone-treated galliwasps was longer than previously reported in other studies. This study determined that a single injection of alfaxalone at 15 mg/kg administered intramuscularly can be used for consistent induction and maintenance of anesthesia and prompt recovery in the Haitian giant galliwasp, while ketamine hydrochloride even at 40 mg/kg was unreliable and is not recommended as a sole immobilization agent in the Haitian giant galliwasp.

• Alfaxalone - neuroactive steroid injectable anesthetic that modulates neuronal cell membrane chloride ion transport by binding to gamma-aminobutyric acid cell surface receptors
  
  • Dose dependent hypotension, bradycardia, resp depression, and apnea in reptiles
• Ketamine hydrochloride is a dissociative general anesthetic agent that works via antagonism of N-methyl-D-aspartate receptors
  
  • May cause respiratory depression, hyper- tension, and bradycardia or tachycardia
• Alfaxalone 15mg/kg IM resulted in reliable induction, anesthesia, and recovery
  
  • Anesthesthetic duration longer than ketamine and longer than other lizard species (57.7 ± 23.6). Likely result of different dose and administration in other lizard studies
  • Little variability in individual anesthetic depth compared to ketamine
  • Fast recovery
• Ketamine 40mg/kg IM did NOT result in consistent induction and maintenance
  
  • More variable individual anesthetic or sedative depth
  • Longer recovery compared to alfaxalone
• Majority of galliwasps maintained body temp within POTR despite being in room temperature (suprising result)

Take home: Alfaxalone IM can be used for consistent anesthesia and prompt recovery in the Haitian giant galliwasp, while ketamine was unreliable and is not recommended as sole agent

Question 69

A recent study evaluated ophthalmic disease in leopard geckos.

How prevalent is ophthalmic disease in this species?

What are teh most common clinical signs and diseases?

Answer 69

Wiggans, K. T., Sanchez-Migallon Guzman, D., Reilly, C. M., Vergneau-Grosset, C., Kass, P. H., & Hollingsworth, S. R. (2018). Diagnosis, treatment, and outcome of and risk factors for ophthalmic disease in leopard geckos (Eublepharis macularius) at a veterinary teaching hospital: 52 cases (1985–2013). Journal of the American Veterinary Medical Association, 252(3), 316-323.

OBJECTIVE: To describe diagnosis, treatment, and outcome of and risk factors for ophthalmic disease in leopard geckos (Eublepharis macularius) evaluated at a veterinary teaching hospital.

DESIGN: Retrospective case series.

ANIMALS: 112 of 144 (78%) leopard geckos that were evaluated at a veterinary teaching hospital in January 1985 through October 2013 and for which sufficient medical record information was available.

PROCEDURES: Information from medical records was used to identify leopard geckos with ophthalmic disease, characterize cases, and determine risk factors for the presence of ophthalmic disease.

RESULTS: Of the 112 leopard geckos, 52 (46%) had ophthalmic disease (mainly corneal or conjunctival disease). Female geckos were less likely to have ophthalmic disease, and there was a positive association between increasing age and ophthalmic disease. Use of a paper towel substrate, absence of any heat source, and lack of vitamin A supplementation were positively associated with a diagnosis of ophthalmic disease. Head dysecdysis was the only concurrent disorder significantly associated with ophthalmic disease. At necropsy, 5 affected leopard geckos had squamous metaplasia of the conjunctivae.

CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ophthalmic disease is a common finding in leopard geckos. The cause of ocular surface disease in leopard geckos may be multi-factorial, and hypovitaminosis A may be an important risk factor. Although animals receiving supplemental vitamin A were less likely to have ophthalmic disease, further understanding is required regarding the metabolism of and nutritional requirements for vitamin A in leopard geckos.

• Positively associated with ophthalmic disease – male, paper towels (previously switched likely), no heat, no vitamin A, dysecydysis
• 52/112 had ophthalmic disease
  
  • All had blepharospasm
  • 44% had ocular discharge
    
    • 78% of discharge was solid or dried, 15% was caseous, 8% was mucoid
  • Diseases
    
    • Conjunctivitis – 12%
    • Nonulcerative keratitis – 23%
    • Ulcerative keratitis – 23%
    • Anterior uveitis – 6%, Other diagnoses – 13%

Take Home:

• Ophthalmic diseases are common in LG. Recommend rocky terrain or PT rather than granular substrates. Debate on vitamin A supplementation.

References: Hausmann JC, Hollingsworth SR, Hawkins MG, et al. Distribution and outcome of ocular lesions in snakes examined at a veterinary teaching hospital: 67 cases (1985–2010). J Am Vet Med Assoc 2013;243:252–260.

Question 70

A recent study investigated the presence of a novel adenovirus in multiple reptile species.

What are teh clinical signs fo agamid adenovirus 1?

What was the novel adenovirus identified?

What species was it found in?

Answer 70

Benge, S. L., Hyndman, T. H., Funk, R. S., Marschang, R. E., Schneider, R., Childress, A. L., & Wellehan, J. F. (2019). Identification of Helodermatid Adenovirus 2 in a captive central bearded dragon (Pogona vitticeps), wild Gila monsters (Heloderma suspectum), and a death adder (Acanthophis antarcticus). Journal of Zoo and Wildlife Medicine, 50(1), 238-242.

Abstract: Adenoviruses are medium-sized DNA viruses with very high host fidelity. The phylogenetic relationships of the adenoviruses strongly resemble that of their hosts, consistent with evolutionary codivergence. The genus Atadenovirus appears to have evolved in squamate hosts. Perhaps the best known of the squamate adenoviruses is Agamid adenovirus 1 (AgAdV1), found most commonly in central bearded dragons (Pogona vitticeps), where it is a prevalent cause of hepatitis/enteritis, especially in young animals. All previous reports of adenoviruses in bearded dragons were AgAdV1. Helodermatid adenovirus 2 (HeAdV2) was first seen in Mexican beaded lizards (Heloderma horridus). Subsequently, partial adenoviral polymerase gene sequence from a western bearded dragon (Pogona minor) in Australia was found to share 99% nucleotide homology with HeAdV2. This article reports the discovery of a virus identical to HeAdV2 in a captive central bearded dragon in Florida and wild Gila monsters (Heloderma suspectum) in Arizona. Additionally, a partial adenoviral polymerase gene sharing 98% homology with this HeAdV2 was discovered in a death adder (Acanthophis antarcticus) in Australia. These findings call into question the provenance of HeAdV2. Further studies of atadenoviral host range, diversity of adenoviruses in captive animals, and characterization of adenoviruses from wild squamates are indicated.

• 5 accepted genera of adenoviruses (Matadenovirus, Aviadenovirus, Atadenovirus, Ichtadenovirus and Siadenovirus)
• Clinical signs associated with Agamid adenovirus 1= lethargy, weakness, diarrhea, sudden death with enterohepatic lesions noted.
• Gila monsters are in closely related Helodermatidae
• Lack of host specificity for HeAdV2
  
  • Adenoviruses are generally considered “host-specific” but there have been reports of cross over
• First report in a bearded dragon for HeAdV2
• HeAdV2 has unique virion architecture which may account for relaxed host specificity
• Unclear how transmission may have occurred between wild and captive populations

Question 71

Describe the affects of atheriosclerosis in affected bearded dragons?

How does it affect the electrophysiology of the heart?

Answer 71

Schilliger, L., Paillusseau, C., Gandar, F., Desprez, I., Claude, W., Passavin, P., … & Chetboul, V. (2019). Hypertensive heart disease and encephalopathy in a central bearded dragon (pogona vitticeps) with severe atherosclerosis and first-degree atrioventricular block. Journal of Zoo and Wildlife Medicine, 50(2), 482-486.

Abstract: A 0.5 kg, 5-yr-old male bearded dragon (Pogona vitticeps) presented with a 2-mo history of lethargy, anorexia, and impaired locomotion. Upon physical examination, bradyarrhythmia (heart rate: 20 beats/min) and balance disorders were noted. Electrocardiography revealed a first-degree atrioventricular block (P-R interval: 360 ms). On echocardiography, all cardiac chambers were slightly above normal ranges. Complete blood count, blood biochemistry, and T4 were unremarkable except for mildly elevated aspartate aminotransferase. Adenovirus testing was negative by polymerase chain reaction. Following euthanasia, necropsy revealed marked thickening of the arterial trunks and histopathology confirmed multifocal atherosclerosis of efferent heart vessels, arteriosclerosis of cerebral arterioles, and multifocal spongiosis of brain tissue, more pronounced in the optic chiasma. Owing to its severity, atherosclerosis may have contributed to chronic arterial hypertension with damages to the heart, brain vessels, and brain tissue-optic chiasma.

• Animal lethargic with delayed righting reflexes and postural abnormalities.
• No heart murmur on doppler
• Electrodes for ECG placed using modified Einthoven triangle with cranial electrodes near ears and inguinal region
  
  • Noted prolonged P-R interval (360ms, first degree AV block)
• Bloodwork unremarkable aside from elevated AST (105). T4 normal for other species
• Adenovirus negative, no parasites in fecal
• Necropsy and histopath as above
• Spongiosis pronounced in optic chiasm, pons and medulla oblongata
• Atherosclerosis is poorly documented in reptiles; AV block not reported
• Challenges with use of ECG in reptiles: amplitudes low with lack of standard parameters
• Cause of first degree AV block unknown- possibly myocardial remodeling as in parrots with atherosclerosis
• In reptiles, dominant pacemaker of heart is a ring of myocardium with nodal characteristics at the SA junction
• Atherosclerosis is rare or underdiagnosed in reptiles; arteriosclerosis (calcification of vessel walls with dilatations) more frequently reported
• In birds, primary arterial hypertension can induce atherosclerosis, or hypertension can result from atherosclerosis due to increase in SVR
• Presumed hypertension in this case due to increased afterload and mild cardiomegaly noted on necropsy. No myocardial lesions.
• Brain CT and cardiac ultrasound were not effective in diagnosing atherosclerosis antemortem in this case

TAKE HOME:

• Atherosclerosis can affect bearded dragons
• Clinical signs include lethargy and postural abnormalities

Question 72

A recent paper describe the repair of traumatic mandibular fractures in a bearded dragon.

What was their technique?

What type of dentition do bearded dragons have?

Why does this matter in healing?

Answer 72

Nau, M. R., & Eshar, D. (2018). Rostral mandibular fracture repair in a pet bearded dragon (Pogona vitticeps). Journal of the American Veterinary Medical Association, 252(8), 982-988.

CASE DESCRIPTION A 2-year-old male bearded dragon (Pogona vitticeps) was evaluated because of a traumatic mandibular fracture.

CLINICAL FINDINGS An open comminuted fracture of the rostral aspect of the right mandible was evident, with a fragment of bone exposed and dorsally displaced. Whole-body radiography revealed no evidence of additional injury. Other findings were unremarkable, except for moderate anemia (PCV, 19%).

TREATMENT AND OUTCOME The fracture fragments were stabilized with 2 crossed 36-gauge interfragmentary wire loops. An external fixator device was fashioned from four 25-gauge needles inserted at alternating angles through the fracture fragments; plastic IV fluid line tubing filled with dental acrylic was used as a connecting bar. One day after surgery, the lizard had regained its typical activity level and appetite. Body weight was measured and the external fixator was inspected 1 week after surgery and monthly thereafter. Three months after initial injury, the fracture was stable, radiography revealed bony callus formation at the fracture site, and the external fixator was removed. Recheck radiography performed 5.5 months after initial injury revealed complete osseous union of the fracture fragments, and the interfragmentary wires were removed.

CLINICAL RELEVANCE Surgical management of the traumatic comminuted mandibular fracture in this bearded dragon by means of a combination of internal and external fixation resulted in complete healing of the mandible and restoration of function. Management of this complicated fracture was achieved with the aid of readily available and inexpensive supplies in a clinical setting, which may be useful to other clinicians in the management of similar cases.

Key points:

• 2 yo M bearded dragon presented with an open comminuted fracture of the rostral right mandible
• The fracture fragments were stabilized with 2 crossed 36-gauge interfragmentary wire loops.
• An external fixator device was fashioned from four 25-gauge needles inserted at alternating angles through the fracture fragments; plastic IV fluid line tubing filled with dental acrylic was used as a connecting bar.
• Regained typical activity level and eating soft food 24 hours post op
• Wires removed 5.5 months after initial injury, callous well formed with small area of periosteal reaction due to chronic implant placement
• Bearded dragons have acrodont dentition, characterized by teeth that are attached directly to the bone of the mandible. Relatively little soft tissue surrounds the bone of the mandible, particularly on the buccal surface, where only a thin layer of gingiva is adhered to the bone and does not extend all the way to the dorsal margin. This is an important consideration for fracture healing, given that the surrounding soft tissues often provide blood supply to the fragments.
• A considerable advantage to the use of the external fixator for the bearded dragon was the rapid return to typical behavior that it allowed without a need for a feeding tube placement

Question 73

A recent study described an outbreak of ranavirus in Meller’s chameleons.

What virus was implicated in the study?

What were the clinical signs?

What were the lesions on necropsy? What were the inclusion bodies?

What is the most common ranavirus - how does that affect reptiles?

What management implications were suggested?

Answer 73

Peiffer, L. B., Sander, S., Gabrielson, K., Pessier, A. P., Allender, M. C., Waltzek, T., … & Mangus, L. M. (2019). Fatal ranavirus infection in a group of zoo-housed meller’s chameleons (trioceros melleri). Journal of Zoo and Wildlife Medicine, 50(3), 696-705.

Abstract: A group of five juvenile Meller’s chameleons (Trioceros melleri) experienced 100% mortality over a period of 1 mo due to ranavirus infection. The index case was found dead without premonitory signs. The three subsequent cases presented with nonspecific clinical signs (lethargy, decreased appetite, ocular discharge) and were ultimately euthanatized. The final case died after initially presenting with skin lesions. Postmortem examination revealed thin body condition in all five animals and mild coelomic effusion and petechiae affecting the tongue and kidneys of one animal. Microscopically, all animals had multifocal necrosis of the spleen, liver, and kidney; four of five animals had necrosis of the nasal cavity; and two of five had necrosis of adrenal tissue, bone marrow, and skin. Numerous basophilic intracytoplasmic inclusions were present in the liver of all animals and nasal mucosa of three of the five animals. Consensus polymerase chain reaction for herpesvirus and adenovirus were negative, whereas ranavirus quantitative polymerase chain reaction was positive. Virus isolation followed by whole genome sequencing and Bayesian phylogenetic analysis classified the isolates as a strain of frog virus 3 (FV3) most closely related to an FV3 isolate responsible for a previous outbreak in the zoo’s eastern box turtle (Terrapene carolina carolina) group. This case series documents the first known occurrence of ranavirus-associated disease in chameleons and demonstrates the potential for interspecies transmission between chelonian and squamate reptiles.

• Ranaviruses – Large, enveloped, dsDNA.
  
  • Infect wide range of ectothermic vertebrates.
  • Seven recognized species of virus – Frog virus 3 most thoroughly researched.
    
    • FV3 and FV3-like viruses emerging pathogens in reptiles – Chelonians, snakes, lizards.
    • Other iridoviruses that are reported in chameleons – Lizard erythrocytic virus, invertebrate iridovirus Gryllus bimaculatus iridescent virus.
  • CS in chameleons – Anorexia, ocular discharge, dehydration, lethargy, oral petechiae, sudden death, skin lesions (one individual).
  • Necropsy – Necrosis of hematopoetic tissues (spleen), liver, kidneys, adrenals, necrotizing inflammation within nasal cavity, oral mucosa, and skin.
    
    • Intracytoplasmic basophilic inclusions numerous and affected a greater variety of tissues vs previous reptile infections in other spp.
    • Secondary bacterial and fungal infections.
  • This ranavirus spp closely related to box turtle FV3 and suspected to be directly or indirectly transmitted from a population of box turtles at this facility.
• Takeaway: Mortality associated with ranaviral outbreak in Meller’s chameleons, nearly identical isolate to EBT ranaviral isolate, suggests interspecies transmission or a shared source of infection. Possible exposure – iatrogenic, direct contact with managed or free-ranging animals, environmental sources. Don’t mix reptile species in exhibits. Intracytoplasmic inclusions!

Question 74

A recent study described salpingotomy in a shingbleback skink.

What was unique about the closure in this case?

Answer 74

McLaughlin, A., & Strunk, A. (2019). Salpingotomy in a Shingleback Skink (Tiliqua rugosa) with Subsequent Successful Parturition. Journal of Herpetological Medicine and Surgery, 29(1), 27-33.

A 5-yr-old female shingleback skink (Tiliqua rugosa) presented for anorexia and lethargy 3 wk after producing a single healthy fetus. Three deceased fetuses were identified within the oviduct on radiographs. A salpingotomy was performed to remove the fetuses, and the patient made an unremarkable recovery from surgery. The skink produced normal offspring 1 yr later. Salpingotomy should be considered as an alternative to ovariectomy and/or salpingohysterectomy in cases of oviductal disease in valuable breeding animals experiencing dystocia.

• Dystocia in reptiles – obstructive anatomic abnormalities, physiologic abnormalities, inadequate husbandry.
• Shingleback skink – spp of blue-tongued skink native to Australia.
  
  • Socially monogamous breeding behavior, prolonged courtship periods (months).
  • Breeding pairs utilize and return to same home territories annually.
  • Viviparous, chorioallantoic placenta and yolk sac placenta aka omphaloplacenta.
    
    • All viviparous squamates have some degree of placental membrane development that allows for a range of physiologic exchanges between the fetus and maternal tissues.
    • Skinks (family Scincidae) – Complex placental membrane development.
• 5yo captive bred female; CS – anorexia, sudden lethargy, gravid. Bred 137 days earlier, 1 healthy offspring 3 wks before presentation, coelom remained distended.
• Rads – confirmed 3 fetuses with mineralized skeletons, no conclusive evidence they were deceased.
• Exploratory surgery – Paramedian incision, two fetuses in right oviduct, left had one.
  
  • Fetuses confirmed deceased and were removed through oviductal incisions.
  • Malodorous fluid within oviducts was cultured but not submitted (owner).
  • Owner did not want ovariosalpingohysterectomy to preserve breeding ability.
  • Salpingotomy was elected instead.
• Post-op: Fluids, morphine, ceftaz. Switched to tramadol, discontinued (sedate). Meloxicam.
• Doing well at 12 day recheck, one year later produced 3 healthy offspring.
• Cause for fetal death in this case never determined.
• Shingleback skink breeders should be encouraged to seek vet care for animals if parturition is interrupted for more than 24 hours.
• Intradermal suture layer incorporating the fascia underlying the osteoderms recommended for skin closure.

Takeaway: Salpingotomy should be considered as an alternative to ovariectomy or salpingohysterectomy in cases of bacterial salpingitis. Intradermal suture layer recommended in skinks.

Question 75

What is the most common mycobacteria to affect reptiles?

What is teh typical presentation?

A recent study described a less common presentation in a veiled chameleon - what was that?

Answer 75

Martinson, S. A., Skjonsberg, C., Muckle, C. A., & Spears, J. (2019). Acute septicemia in a hermaphrodite veiled chameleon (Chamaeleo calyptratus) infected with Mycobacterium chelonae Chemovar niacinogenes. Journal of Herpetological Medicine and Surgery, 29(1), 21-26.

Abstract : A 2-yr-old male veiled chameleon (Chamaeleo calyptratus) was presented for open-mouthed breathing, lethargy, and progressive deterioration culminating in euthanasia. Postmortem examination revealed red discoloration of the lungs, liver, and coelomic fat pads and mild fluid accumulation in the coelom. Histopathological evaluation revealed acute septicemia characterized by numerous intravascular acid-fast bacteria and intravascular fibrin thrombi in multiple organs. Bacteriologic culture of the lung yielded heavy growth of Gram-positive, acid-fast pleomorphic bacilli which were identified as Mycobacterium chelonae chemovar niacinogenes with the use of 16s and hsp65 gene sequencing. The gonads were determined to be ovotestes. To the authors’ knowledge, this is the first report of acute Mycobacterium chelonae septicemia in a veiled chameleon and also the first report of hermaphroditism in this species.

Mycoplasma sp.- Opportunistic with underlying illness, poor nutrition or suboptimal husbandry

• Only nontuberculous mycobacteria reported in reptiles. Most common isolates: M. marinum, M. chelonae and M. thamnopheos
• Rapidly growing species develop biofilms à allows growth in harsh environments + resistance to disinfectants + antibiotics
• Typical presentation: chronic, granulomas in multiple organs w/ bacteria in the cytoplasm of ¢ or free in necrotic center of granulomas; rarely subacute or acute
• Zoonotic potential esp. in immunocompromised individuals (various locations of infection). Poor response to tx and zoonotic potential - euthanasia recommended
• 2 YO chameleon w/ open-mouth breathing and lethargy that deteriorated ++ despite enrofloxacin tx and was euthanized
• Radiographs revealed interstitial lung pattern and horizontal soft tissue interface resembling fluid line in coelom
• Macroscopic postmortem: red discoloration of the lungs, liver, and coelomic fat pads and mild fluid accumulation in the coelom; single chronic granuloma in small intestine
• Histopath: gram positive, acid-fast under Ziehl-Neelsen bacilli in macrophages and extra¢ in blood vessels cultured as Mycobacterium chelonae chemovar niacinogenes + evidence of hermaphroditism (testes w/ ovarian follicles)
• Final diagnosis: subacute systemic infection w/ subsequent acute bacterial septicemia and disseminated intravascular coagulation
• Only one other report of acute mycobacterial sepsis in a reptile: eastern spiny softshell turtle that was also infection w/ M. chelonae
• M. chelonae should be considered as a ddx for acute sepsis in reptiles
• Heterophilic response generally expected, but inflammatory response in this chameleon was mild
• Likely route of entry via infected water or food (granuloma in intestine)

Take home: Mycoplasma chelonae typically causes chronic infection and granulomas but can also result in acute septicemia in reptiles

• Dx supported by presence of gram positive, acid-fast bacilli in blood vessels and macrophages

Question 76

A recent study described an endocrine neoplasm in komodo dragons.

What is the scientific name of the komodo dragon?

What neoplasia was found?

How did they confirm the tumor type?

Answer 76

Eustace, R., Garner, M. M., Cook, K., Miller, C., & Kiupel, M. (2017). Multihormonal islet cell carcinomas in three komodo dragons (varanus komodoensis). Journal of Zoo and Wildlife Medicine, 48(1), 241-244.

Abstract: Multihormonal pancreatic islet cell carcinomas were found in one female and two male captive geriatric Komodo dragons (Varanus komodoensis). Gross changes in the pancreas were visible in two of the cases. Clinical signs noted in the Komodo dragons were lethargy, weakness, and anorexia. Histologically, the tumors were comprised of nests and cords of well-differentiated neoplastic islet cells with scant amounts of eosinophilic cytoplasm and round, euchromatic nuclei, with rare mitoses. Infiltration by the islet cell tumor into the surrounding acinar tissue was observed in all cases, but no metastatic foci were seen. Multihormone expression was observed in all tumors, which labeled strongly positive for glucagon and somatostatin and focally positive for polypeptide. Pancreatic islet cell neoplasms should be considered in the differential diagnosis for geriatric Komodo dragons presenting with weakness, lethargy, and poor appetite.

• Case 1
  
  • Bilateral hind limb weakness and constipation
  • Bloodwork, blood culture, CT - no cause found
  • Meloxicam, tramadol, ceftaz - died 6wk later
  • Islet cell tumor on splenopancreas on necropsy
• Case 2
  
  • Lethargy
  • Danofloxacin and fluids - no improvements
  • Chemistry - hyperuricemia
  • Started allopurinol - no improvement
  • Euthanasia and necropsy - visceral gout and islet cell tumor on splenopancreas
• Case 3
  
  • Found dead after a 2-day history of lethargy and hunched posture
  • Necropsy - 360-degree mesenteric torsion and islet cell tumor on splenopancreas
• IHC - cancer cells diffusely strongly positive for glucagon and somatostatin
  
  • IHC gold standard to determine functional subclassification of pancreatic tumors
• Large concentration of islet tissue located in distinct juxtasplenic islet body connected to dorsal lobe of pancreas by thin stalk in monitor lizards – unique to these lizards

Question 77

A recent study evaluated the prevalence of Salmonella in Grand Cayman iguanas.

What is the scientific name of the Grand Cayman or Blue Iguana?

Pet-related salmonellosis accounts for what amount of salmonella cases?

What was the prevalence in the GC iguanas?

Answer 77

Prud’homme, Y., Burton, F. J., McClave, C., & Calle, P. P. (2018). Prevalence, incidence, and identification of Salmonella enterica from wild and captive Grand Cayman iguanas (Cyclura lewisi). Journal of Zoo and Wildlife Medicine, 49(4), 959-966.

Abstract: From 2005 to 2017, a total of 334 fresh fecal samples was obtained from 236 captive and free-ranging Grand Cayman iguanas (Cyclura lewisi) in a captive breeding and release program. One-hundred-sixteen samples were obtained from individual captive iguanas living in enclosures with natural substrate, 161 samples from captive iguanas living in elevated wire-bottom enclosures, and 57 samples from free-ranging wild iguanas. These samples were cultured to isolate subspecies of Salmonella enterica. as part of prerelease health evaluations, and to determine baseline health assessments of captive and wild populations of these iguanas. There was a 5.45% (95% confidence interval [CI]: 1.14–15.12) prevalence of S. enterica in iguanas housed on natural substrate (n = 51), 3.85% (CI: 1.42–8.19) in iguanas housed in elevated wire-bottom enclosures (n = 157), and 6.06% (CI: 0.74–20.23) in wild free-ranging iguanas (n = 38). These results demonstrate no significant difference (P = 0.73) in S. enterica prevalence among these housing conditions. The incidence of S. enterica from 2005 to 2017 in the population sampled was 4.19% (CI 3.10–5.29). Ten different serotypes of S. enterica were isolated from 14 iguanas. Salmonella enterica ser. Saintpaul was the most frequent isolate. Annual S. enterica prevalence was calculated for iguanas housed in different enclosure types, for free-roaming wild iguanas, and for all cultured iguanas. The highest yearly prevalence was 23.08% (CI: 5.04–53.81) in iguanas tested in 2007 (n = 21). No Salmonella enterica were cultured in 2005, 2008, 2009, 2010, 2011, 2012, and 2015. These results suggest that the shedding of S. enterica was not significantly different between housing types or between captive versus wild iguanas and therefore that release of captive iguanas did not significantly affect the health of the wild population or their exposure to S. enterica.

• Grand Cayman iguana (blue iguana) – decline in 2002 down to 20 individuals – habitat destruction, hunting, introduced predators – population now up to 1000
• Salmonella enterica
  
  • Known zoonosis – 6% of human salmonellosis cases are pet-related (74,000 cases annually)
  • Wild reptiles as source – RES in china, skinks in NZ
• Prevalence on island reptiles
  
  • Low prevalence in GCI – 5.45% consistent with 0-6.6% prevalence in free-ranging reptiles
  • Galapagos iguanas have higher prevalence (45-98%)
  • Tuataras and skinks in NZ have lower prevalence (0, 6.5%)
• Limitations
  
  • Frozen samples may not be as good (previous study said they were fine statistically)
  • Intermittent shedding may result in underestimated prevalence
• No risk to introducing salmonella to wild population

Take Home: CGI in managed settings have similar Salmonella enterica prevalence to wild reptiles (5.45%) and Saintpaul was the most frequently isolate serovar.

Question 78

A recent study described a method for jugular venipuncture in the common chameleon.

What was the technique?

Answer 78

Eshar, D., Lapid, R., & Head, V. (2018). Transilluminated Jugular Blood Sampling in the Common Chameleon (Chamaeleo chamaeleon). Journal of Herpetological Medicine and Surgery, 28(1-2), 19-22.

Abstract: Blood collection in chameleons is indicated in clinical cases and research studies and is commonly performed from the ventral tail vein. However, this venipuncture site can be associated with a greater degree of technical difficulty, adverse effects, and artifactual changes in the test results. The jugular vein is often suggested as a preferred alternative sampling site, but can also be technically challenging in smaller lizards. A transillumination method of the cervical region that reveals the jugular vein can be used for more accurate venipuncture, increased sampling success, as well as reduced handling time and soft tissue damage to adjacent anatomical structure. The technique described in this report can be used to collect blood from common chameleons (Chamaeleo chamaeleon).

• Commonly accepted venipuncture sites in chameleons - ventral tail vein and jugular vein
  
  • Ventral abdominal vein and cardiac sampling can also be performed but more risk of visceral damage
• Tail vein venipuncture
  
  • Ventral or lateral tail veins
  • Restraint in either ventral or dorsal recumbency
  • May encounter lymph dilution
  • Blind stick
  • Risk of color darkening, tissue damage, increased blood collection time, and increased rates of failure to obtain useable sample
• Jugular venipuncture
  
  • Minimize some of limitations with tail sampling
  • Restrained in lateral recumbency
  • Needle inserted blindly at ~45-degree angle parallel to lumen of jugular, which lies caudal to ramus of mandible or tympanum and courses caudoventrally toward point of shoulder
  • Blind stick challenging and risks increased handling stress, pain, tissue damage to carotid artery and vagus nerve
  • Jugular vein relatively superficial to lymphatics
    
    • Hemodilution via lymph contamination is a risk
    • Hemodilution reduced by creating ~ 45-degree bend in needle
• Transilluminated jugular venipuncture
  
  • Light below venipuncture sight allows visualization of jugular
  • 23–27G needle bent at hub by 45-degree angle on 1-mL heparinized syringe and inserted parallel to lumen of vein
  • More accurate and faster blood sampling and minimizes stress, pain, and tissue trauma
  • Superior to ventral tail sampling in retrospective study

Question 79

A recent study evaluated bile acids and protein electrophoresis in Captive Panther cameleons.

What is the scientific name of the panther chameleon?

How did bile acids compare to other species?

What was teh predominant fraction in the EPH?

What changes occurred with disease in the EPH?

Answer 79

Laube, A., Altherr, B., Clauss, M., & Hatt, J. M. (2018). Reference Intervals for Bile Acids and Protein Electrophoresis in Plasma of Captive Panther Chameleons (Furcifer pardalis): A First Approach. Journal of Herpetological Medicine and Surgery, 28(3-4), 99-106.

Abstract Bile acids are considered a sensitive indicator for liver function in mammals and birds, and protein electrophoresis is a routine test used in mammals to differentiate inflammatory responses. The objective of this study was to establish reference intervals for bile acids and protein electrophoresis in clinically healthy panther chameleons (Furcifer pardalis) under similar husbandry conditions. Blood samples from 84 captive panther chameleons were collected in January and August from the ventral coccygeal vein and processed for protein capillary zone electrophoresis and enzymatic–photometric measurements of bile acids. Reference intervals for bile acids were similar to other reptile species, but those for protein electrophoresis differed considerably, with a-globulins as the second most predominant fraction after albumin. Significant differences between males and females were found in a1- and c-globulin fractions. Three diseased panther chameleons that died within a few months after sampling had an albumin– globulin ratio below the reference interval.

• The objective of this study was to establish reference intervals for bile acids and protein electrophoresis in clinically healthy panther chameleons (Furcifer pardalis) under similar husbandry conditions.
• 84 captive panther chameleons sampled
• Protein electrophoresis and bile acids were measured and reference intervals were established.
• BA reference interval similar to other species
• Protein electrophoresis differed considerably, with alpha-globulins (particularly alpha2) as the second most predominant fraction after albumin
• No significant differences in BA based on sex, gravid status, or season
• Significant differences between males and females were found in a1- and c-globulin fractions.
• Three diseased chameleons had protein profiles that strongly diverged from the reference intervals, with increased alpha1, alpha2 and beta globulins in 2 males and increased overall globulins in one female. All three had very low albumin:globulin ratios

Question 80

A recent study evaluated the hematology, biochemistry, and protein electrophoretogram of the blue iguana.

What are the largest two fractions of the EPH?

What is the predominant leukocyte?

What values changed with season?

What values varied by age?

Answer 80

Rainwater, K. L., McClave, C., Raphael, B. L., Cray, C., Franklin, A. D., Powell, D. M., … & Calle, P. P. (2021). Hematology, plasma biochemistry, and plasma protein electrophoresis reference intervals for blue iguanas (Cyclura lewisi) from Grand Cayman Island. Journal of Zoo and Wildlife Medicine, 51(4), 933-947.

Abstract: The blue iguana (Cyclura lewisi) is an endangered rock iguana species native to Grand Cayman, in the Cayman Islands. Health assessments were conducted on captive and free-roaming iguanas in 2001 and 2003–2014 and were performed in the summer wet season (June–July) of 2003–2004 and 2010–2014 and in the winter dry season (November–December) of 2001 and 2005–2009. Morphometric data were recorded from iguanas when blood samples were collected: 903 samples were collected and data from 890 samples from 775 iguanas were included. Samples were analyzed for hematology, plasma biochemistry, protein electrophoresis, mineral panels, 25-hydroxyvitamin D, and testosterone. Reference intervals were created for captive subadults, captive adults, and free-roaming adults when data were sufficient. Significant differences among these groups were described, as were differences on the basis of sex, season, and origin (captive vs free-roaming). In captive iguanas, most analytes were significantly different between subadults and adults, mature heterophils and copper were significantly higher in the dry season, zinc levels were significantly higher in the wet season, and cholesterol and triglycerides were significantly higher in adult females than adult males. Testosterone in adult males was significantly higher in the dry season. These results will aid in future health assessments and disease investigations in wild and captive populations of blue iguanas and are of comparative value for other Cyclura species that are free-roaming, captive, and, especially, in similar conservation release programs.

• Goal to determine reference intervals for hematology, plasma biochemistry, protein electrophoresis, trace mineral analytes, vitamin D3, testosterone
• N = 890 blood samples from 775 iguanas
  
  • Compared free ranging (FA) and captive adult (CA) and free ramging subadult (FS) and captive subadults (CS)
• Band heterophils, lymphocytes, monocytes, eosinophils, EPH TP, A:G ratio, albumin percentage, total globulins, alpha 2 globulins, beta globulins, colorimetric TP, and glucose – significantly different between summer and winter, but not clinically significant
• Key points
• Wide reference range for total WBC in captive subadult, (higher upper limit) CA, and FA
• Basophils higher in CS than CA
• Heterophils most numerous leukocyte in CA and FA, lymphocytes in CS
• PCV similar across CS, CA, FA (slightly higer RI in CA, FA)
• Glucose, CK, lactate, cholesterol, triglycerides differ between CS and CA
• Albumin is largest protein fraction on EPH, followed by beta globulin
• EPH TP, total globulins, gamma globulins higher in CA than CS
• No difference between calcium in CA males and females, but maximum values for calcium in all groups were females
• Vitamin D3 higher in CS than CA
• Copper higher in winter and in CA
• Zinc higher in summer and in CS
• Increase in testosterone leading up to breeding season with lower levels in summer

Question 81

A recent study compared the efficacy of silver sulfadiazine and photobiomodulation on wound healing in green iguanas.

Describe the healing process in reptiles.

How does photobiomoduclation work?

Describe the use of SSD in wound healing.

How did SSD or PBMD affect wound healing?

Answer 81

Cusack, L. M., Mayer, J., Cutler, D. C., Rissi, D. R., & Divers, S. J. (2018). Gross and histologic evaluation of effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product on experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana). American journal of veterinary research, 79(4), 465-473.

OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana). ANIMALS 16 healthy subadult green iguanas.

PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm² or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity.

RESULTS On day 14, wounds treated with a laser at 10 J/cm² were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments.

CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm² appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

• Integumentary injury in lizards – Characterized by inflammatory and vascular response.
  
  • Inflammatory response in lizards minimal vs snakes.
  • Followed by fibroblast response freom adjacent dermis, as opposed to response in mammals that is from the underlying SQ tissues.
  • Restoration of the epidermis and maturation of epithelium follow restoration of dermal integrity.
  • Lizards typically form little epithelial scabbing, snakes scabs are more substantial.
  • Mitotic activity of epidermal cells occurs only during ecdysis.
  • Relatively slow rate of healing in reptiles vs mammals.
  • Garter snakes – Healing more rapid at higher temps.
  • Tree lizards – Healing decreased with stress of restraint.
  • Direction of an incision and instrumentation used to create incisions can also affect wound healing in reptiles.
  • Effects of photobiomodulation differe greatly depending on wavelength, energy, energy density, and delivery system.
  • Relatively low rate of healing in wounds treated with SSD, unrexpected. Potentially cytotoxic, shown to delay wound contraction in rats.
• Takeaways: Photobiomodulation safe treatment, well tolerated, resulted in smaller wounds than other treatment groups but histologically there was no difference. SSD also did NOT improve wound healing despite its widespread use and further studies are needed.

Question 82

What is the opioid of choice for tegu analgesia?

Answer 82

Leal, W. P., Carregaro, A. B., Bressan, T. F., Bisetto, S. P., Melo, C. F., & Sladky, K. K. (2017). Antinociceptive efficacy of intramuscular administration of morphine sulfate and butorphanol tartrate in tegus (Salvator merianae). American journal of veterinary research, 78(9), 1019-1024.

Abstract:

OBJECTIVE: To evaluate the antinociceptive efficacy of IM morphine sulfate or butorphanol tartrate administration in tegus (Salvator merianae).

ANIMALS6 healthy juvenile (12- to 24-month-old) tegus (mean ± SD body weight, 1,484 ± 473 g).

PROCEDURES: In a crossover study design, tegus were randomly assigned to treatment or-der, with a minimum washout period of 15 days between treatments. Each of 5 treatments was administered IM in a forelimb: saline (0.9% NaCl) solution (0.5 mL), morphine sulfate (5 or 10 mg/kg), or butorphanol tartrate (5 or 10 mg/kg). A withdrawal latency test was used to evaluate antinociception, with a noxious thermal stimulus applied to the plantar surface of the hind limb before (0 hours; baseline) and 0.5, 1, 2, 3, 4, 6, 12, and 24 hours after each treatment. Observers were unaware of treatment received.

RESULTS: With saline solution, mean hind limb withdrawal latencies (interval to limb withdrawal from the thermal stimulus) remained constant, except at 12 hours. Tegus had higher than baseline mean withdrawal latencies between 0.5 and 1 hour and at 12 hours with morphine at 5 mg/kg and between 1 and 12 hours with morphine at 10 mg/kg. With butorphanol at 5 and 10 mg/kg, tegus maintained withdrawal responses similar to baseline at all assessment points.

CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that morphine, but not butorphanol, provided antinociception at 5 and 10 mg/kg in tegus as measured by thermal noxious stimulus testing. These data supported the hypothesis that μ-opioid (but not κ-opioid) receptor agonists provide antinociception in reptiles.

• Morphine commonly used for analgesia – but produces significant respiratory depression
• Butorphanol has no evidence of respiratory depression and is used for analgesia in some reptile species
• Mu-opioids are better for antinociception in teiids

Take Home: Mu opioids for teiid analgesia

Question 83

A recent study evaluated the pharmacokinetics of ceftiofur crystalline free acid in green iguanas.

What is the scientific name of the green iguana?

What is ceftiofur CFA?

What dose is recommended?

What is the recommended dosing interval?

Answer 83

Sadar, M. J., Hawkins, M. G., Taylor, I. T., Byrne, B. A., & Tell, L. A. (2018). Pharmacokinetics of ceftiofur crystalline free acid sterile suspension in green iguanas (Iguana iguana) after single intramuscular administration. Journal of Zoo and Wildlife Medicine, 49(1), 86-91.

Abstract: The objective of this study was to establish the pharmacokinetic parameters of ceftiofur crystalline free acid (CCFA) for a single intramuscular injection in green iguanas (Iguana iguana). Six green iguanas received an injection of 5 mg/kg CCFA into the triceps muscle. Using high-performance liquid chromatography, concentrations of ceftiofur free acid equivalents in plasma samples collected at predetermined time points were evaluated up to 21 days following drug administration. Noncompartmental pharmacokinetic analysis was applied to the data. The observed maximum plasma concentration (Cmax obs) was 2.765 ± 0.864 lg/mL, and the time of observed maximum concentration (Tmax obs) was 6.1 6 9.2 hr. The area under the curve (0 to infinity) was 239.3 ± 121.1 lghr/mL. No significant adverse drug reactions were clinically observed, and no visible injection site reactions were noted. Minimum inhibitory concentrations of bacterial isolates from iguanas were used to establish a target plasma concentration of 2.0 lg/mL. Based on the results from this study, a potential dosing interval for ceftiofur crystalline free acid administered at 5 mg/kg intramuscularly for iguanas maintained at a temperature of 308C would be 24 hr based on a target plasma concentration of 2 lg/mL; however, multidose studies still need to be performed.

• Ceftiofur – 3^rd generation cephalosporin with broad spectrum for Gram Pos, Gram Neg, and anaerobic bacteria.
  
  • Strep, proteus, E. coli, klebsiella, some staphs.
  • Study with ceftiofur sodium at 5 mg/kg SQ in iguanas q24h showed reach of target concentrations.
  • CCFA is sustained release version.
  • 15 mg/kg IM in ball pythons q5 days; 30 mg/kg IM bearded dragons or SQ plasma concentrations for > 288 hrs.
  • Iguanas are considered food animals in some parts of the world, judicious use is important and extra-label use may not be supported depending on location.
• Takeaway: CCFA 5 mg/kg IM q24h is apparently safe and reaches target conc for many bacteria commonly encountered in green iguana infections.

Question 84

A recent study evaluated the effects of furosemide in bearded dragons.

What is the scientific name of the bearded dragon?

Why do some people think furosemide doesn’t work in reptiles?

How did furosemide affect the bearded dragons?

Answer 84

Parkinson, L. A., & Mans, C. (2018). Effects of furosemide administration to water-deprived inland bearded dragons (Pogona vitticeps). American journal of veterinary research, 79(11), 1204-1208.

ABSTRACT: OBJECTIVE: To evaluate the diuretic effects and associated changes in hematologic and plasma biochemical values following SC furosemide administration to water-deprived inland bearded dragons (Pogona vitticeps). ANIMALS: 9 bearded dragons. PROCEDURES: In a crossover study design, furosemide (5 or 10 mg/kg) was administered SC every 12 hours for 4 doses or no treatment (control treatment) was provided for the same period. Food and water were withheld. Body weight was recorded before (baseline) and 12 hours after treatment sessions ended and then after 5 minutes of soaking in a water bath. Blood samples were collected at baseline and 12 hours after treatment sessions ended for various measurements. RESULTS: Compared with control values, a significant decrease from baseline in body weight was detected after furosemide treatment at 5 and 10 mg/kg (mean ± SD percentage decrease, 5.5 ± 3.2% and 5.2 ± 4.1%, respectively). Soaking resulted in a significant increase in body weight after the 5- and 10-mg/ kg furosemide treatments (mean ± SD percentage increase, 2.9 ± 1.8% and 5.6 ± 2.5%, respectively), compared with change in body weight after the control treatment (0.7 ± 0.7%). Plasma total solids and total protein concentrations increased significantly with both furosemide treatments, and PCV increased significantly with the 10 mg/kg treatment only. No significant or relevant differences were identified in plasma osmolarity or uric acid or electrolyte concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Furosemide as administered resulted in hemoconcentration and weight loss in bearded dragons, most likely owing to its diuretic effects. With additional research, furosemide could be considered for treatment of congestive heart failure and other conditions requiring diuresis in bearded dragons.

• Heart disease is uncommonly reported in reptiles, mixed results w/furosemide in CHF
• Furosemide reduces Na and Cl reabsorption in loops of Henle causing increased water excretion in mammals
  
  • Controversial in reptiles b/c lack loop-of-Henle
  • Furosemide produces diuresis by altering renal tubular electrolyte absorption and renal excretion in chelonians and snakes
• N = 9, complete crossover with furosemide 5 or 10mg/kg SC q12hr for 4 doses vs no treatment. Measured weight 12 hours post treatment and after soaking.
• Repeated administration of furosemide 5 and 10mg/kg resulted in diuresis and dehydration
  
  • Both doses = ↓BW post treatments, ↓BW post soaking, ↑TS and TP
  • ↑PCV with 10mg/kg only
• Plasma osmolarity was expected to be an indicator of the hydration but was NOT
  
  • NO difference in osmolarity, UA, or electrolytes
  • Clinicians should be aware that at a degree of dehydration clinically important in mammals, there was no increase in plasma osmolarity in bearded dragons
• Bearded dragons DID compensate for dehydration with drinking behavior
  
  • Drank twice as much water with 10mg/kg compared to 5mg/kg
  • Drank less than iguanas in similar study 🡪 suggests arid adapted bearded dragons are less prone to environmentally induced dehydration

Take home: Furosemide at 5 and 10mg/kg SC had diuretic effects in bearded dragons, caused dehydration and drinking behavior, NO increase in osmolarity

Question 85

A recent study compared the effect of light-emitting diodes (LED) and UVB supplementation on vitamin D levels in bearded dragons.

Describe the metabolism of vitamin D.

How did 25OHD3 vary between groups?

Were any other biochemical parameters altered?

Answer 85

Cusack, L., Rivera, S., Lock, B., Benboe, D., Brothers, D., & Divers, S. (2017). Effects of a light-emitting diode on the production of cholecalciferol and associated blood parameters in the bearded dragon (Pogona vitticeps). Journal of Zoo and Wildlife Medicine, 48(4), 1120-1126.

Abstract: The importance of vitamin D3 has been documented in multiple reptile species, with deficiencies resulting in alterations in calcium homeostasis, including nutritional secondary hyperparathyroidism. Though vitamin D3 can be obtained directly from dietary sources or from photobiosynthetic production, species variability in diet and behavior makes exposure to ultraviolet B (UVB) radiation an essential requirement for some diurnal species. The effect of different bulbs to promote synthesis of cholecalciferol (vitamin D3) in the bearded dragon (Pogona vitticeps) was evaluated. Individual animals (n ¼ 5 for each group) were exposed to industry standard fluorescent bulbs (UVB), non–UVB producing bulbs (UVBN), and light-emitting diode (LED) UVB (LED) bulbs for a period of 11 mo. Weekly measurements of UV index (UVI) were recorded for each bulb. Plasma vitamin D3, 25-hydroxycholecalciferol (25OHD3), ionized calcium (iCa), total calcium (TCa), and phosphorus (P) were measured at time zero and at 4 mo, 8 mo, and 11 mo. Parameters were measured between groups and time points. There were decreases (P , 0.05) with time for iCa for the LED and UVB groups, for TCa in the UVB group, and for vitamin D3 in the LED and UVBN groups. There were no significant differences between study groups for vitamin D3, iCa, TCa, or P. Overall plasma concentration for 25OHD3 in the LED group was greater than for the UVB (P ¼ 0.0347) and the UVBN (P ¼ 0.0490) groups.

• Provitamin D3 (precursor to cholecalciferol (vitamin D3)) in skin - exposed to UVB - converted to vitamin D3 in skin - vitamin D3 enters bloodstream - hydroxylated into 25-hydroxycholecalciferol (25OHD3) in liver - 25OHD3 (storage form of vitamin D3, most representative of vitamin D3 status) converted into calcitriol (bio active form) in kidney
• Goal - evaluate ability of broad-spectrum light-emitting diode (LED) producing UVB to facilitate synthesis of vitamin D3 and 25OHD3 in bearded dragon and compare with positive (UVB-producing fluorescent bulbs) and negative (non–UVB producing incandescent bulbs) controls
• M+M - bearded dragons exposed to industry standard fluorescent bulbs (UVB), non–UVB producing bulbs (UVBN), and light-emitting diode (LED) UVB (LED) bulbs for a period of 11 months
• Results/discussion:
  
  • no significant differences for iCa, TCa, or P between study groups at any time point
  • LED UVB prototype light was effective in promoting the synthesis of vitamin D3 and 25OHD3 in the bearded dragon for a period of at least 11 months
  • animals exposed to LED bulbs had higher levels of 25OHD3 overall at T4, T8, and T11 when compared to animals in the UVB and UVBN study groups
  • deceased iCa over time with LED and UVB, total Ca in UVB group, and vitamin D3 in LED and UVBN groups
  • 25OHD3 plasma concentration in LED group greater than for UVB and UVBN groups

Question 86

A recent study evaluated the breeding of the crocodile lizard.

What is the scientific name of the crocodile lizard?

Describe the reproductive strategy of this lizard.

How does temperature affect development?

Is their a seaonality to their breeding?

How many babies on average?

Does size or age matter for success?

Answer 86

Li, Q., Luo, S., Yang, C., Li, S., Guo, J., He, J., … & Du, W. (2019). Impacts of maternal characteristics and temperature on juvenile survival in the crocodile lizard: Implications for conservation. Zoo biology, 38(3), 272-280.

Abstract: Captive breeding is an important conservation measure that may restore and enhance wild populations of rare and endangered species. Multiple anthropogenic hazards have brought the crocodile lizard, Shinisaurus crocodilurus, to the brink of extinction. We initiated a captive breeding program and quantified female reproductive traits, including reproductive timing, litter size, litter mass, and neonate size. To identify the internal and external factors affecting female reproductive function, we then analyzed how maternal age is related to body size, temperature, and female reproductive traits. We found that larger female crocodile lizards produced more offspring than smaller ones, as both litter size and litter mass were positively related to maternal body size. In contrast, neonate size was independent of maternal body size. Maternal reproductive output varied among different age groups. Young and old females had significantly smaller living litter size and mass than middle‐aged females. Among captive females, one‐third exhibited early parturition in autumn and winter instead of the following spring, a pattern probably associated with higher ambient temperatures in captivity. Although female reproductive output and neonatal body size did not differ between early‐ and normal‐parturition females, offspring from the former group died earlier than those from the latter. Our study highlights the danger of climate change in hastening parturition, a phenomenon that could significantly hamper neonate survival and impede population recruitment.

• Thermal environment is an important factor in captive reptile breeding that determines reproductive success and offspring quality
  
  • High temps experienced by females can speed up repro timing by enhanced embryonic development rate
• Crocodile lizard; family Shinisauridae - CITES Appendix I
  
  • Viviparous, most females mate in spring and summer (Apr-July)
  • Gravid 9-12 mo, birth in following spring (Apr-May)
• 54 females from 2014-2017; offspring survival followed up to 3.5 yr
• In higher ambient temps, some females matured at 2 yr (as early as 13 mo vs 3-4 yr in the wild)
  
  • Appears to increase reproductive frequency and lifetime output
  • But low reproductive success so likely little contribution to population size
• 33% gave birth in autumn and winter (early), the rest in the following spring (Mar-May; normal)
  
  • Repro output and neonate morphology did not differ
  • Neonates from normal-timed parturition survived longer than early-parturition
  • Suspect early parturition due to higher ambient temps in captivity
  • Neonates from early parturition are more likely to face early environmental threats (winter right after birth, food mismatch)
  • Causes concern for a possible early shift of parturition in response to climate change
• 1 litter per yr, avg 6.4 (3-11) neonates
  
  • Larger females produced more neonates and greater litter mass (up to 160 mm snout-vent length, then decreased thereafter - decreased repro output with age)
  • Living litter size was significantly smaller in younger females but not litter size or mass
• Neonatal size not correlated with maternal size and not different between maternal age groups
  
  • Neonatal body mass was negatively correlated with litter size
• Maternal body size is the major determinant of reproductive output in crocodile lizards when there are no environmental constraints
  
  • Female reproductive output increased with body size and age (highest living neonates in middle-aged ie. 3-4 yo vs 2 yo or >5 yo)
• Larger females produced more offspring than smaller females but neonatal size is independent of maternal body size
  
  • Females boost reproductive output through offspring number rather than size
  • Females likely prioritize offspring size over litter size when allocating limited resources
• In warmer temperatures, crocodile lizards may mature faster (with decreased reproductive success) and result in early parturition ie. autumn vs spring (with shorter offspring survival time)

Question 87

A recent paper described the treament of squamous cell carcinoma in bearded dragons.

What are some predisposing factors to SCC development in reptiles?

Is there a site predilection in reptiles?

What treatments were sucessful?

Answer 87

Schilliger, L., Paillusseau, C., Gandar, F., & De Fornel, P. (2020). IRIDIUM 192 (192-Ir) HIGH DOSE RATE BRACHYTHERAPY IN A CENTRAL BEARDED DRAGON (POGONA VITTICEPS) WITH ROSTRAL SQUAMOUS CELL CARCINOMA. Journal of Zoo and Wildlife Medicine, 51(1), 241-244.

Abstract: A 0.5-kg, 9-yr-old, male central bearded dragon (Pogona vitticeps) presented with a proliferative mass (0.4 3 0.2 inches) on the left rostral aspect of the lower lip. Physical examination, blood work, and whole-body radiography did not reveal any other abnormalities. Histopathology confirmed squamous cell carcinoma. Considering the small size of the tumor, absence of deep tissue infiltration, and its radioresponsive characteristics, iridium 192 high dose rate brachytherapy was attempted. The dragon initially received three doses of 4 Gy/site at days 0, 7, and 17. Recurrence developed 3 mo later. Three more fractions of 6 Gy/site at days 0, 7, and 14 were delivered according to the same procedure. A second recurrence appeared after 2 mo. Surgical excision was then performed, followed by four fractions of 6 Gy/site on the surgical site at 2-wk intervals. Sixteen months posttreatment, no recurrence of the mass was observed.

Brief Comm

• 9yo male bearded dragon with ulcerative and proliferative mass (0.4x0.2) on left mandible
  
  • Sufficient diet, dusted with calcium carbonate
• Incisional biopsy consistent with squamous cell carcinoma infiltrating into the deep dermis
• Iridium-192 high dose rate brachytherapy attempted under anesthesia
  
  • Allowed a small field to be targeted at a large dose in a small volume of tissue
  • Planned using CT and 4D brachytherapy planning system. See abstract.
• SCC is common malignant tumor. Metastasis is rare.
• Excess or improper exposure to UV may be causative factor for SCC in reptiles
  
  • Possible viral etiology or chronic skin inflammation as predisposing factors
• In bearded dragons, predilection for tumors near mucocutaneous junctions on the skin of the head (esp eyelid or periocular tissues)
• Previously attempted treatments:
  
  • Photodynamic therapy using chloro-aluminum sulfonated phthalocyanine, remission after 1 treatment on upper lip lesion and on lower lip after 2 tx on true-red tailed boa
  • 2 sessions electrochemotherapy after surgical excision with intratumoral admin bleomycin and biphasic electric pulses at 2 week intervals removed in nuchal SCC of yellow bellied slider
  • Implanted carboplatin beads in a panther chameleon after sx excision – no recurrence
    
    • Some not resected and did reduce in size with only carboplatin tx
  • Teletherapy- via linear accelerator- 4.8Gy/fx at 10 fractions given 3x/week led to significant tumor regression
  • Strontium-90 plesiotherapy (100Gy/site) attempted on myxosarcoma periocular mass, re-appeared 5mo later
  • Radiation therapy on pharyngeal SCC resistant to palliative therapy (10Gy weekly x3 weeks) in a boa, led to radiation associated vasculitis

Question 88

A recent study evaluated the effect of cricket meals on uric acid in bearded dragons.

List some uricotelic and ureotelic reptiles.

How did cricket ingestion affect uric acid in the beardies?

Answer 88

Parkinson, L. A., & Mans, C. (2020). Investigation of the effects of cricket ingestion on plasma uric acid concentration in inland bearded dragons (Pogona vitticeps). Journal of the American Veterinary Medical Association, 257(9), 933-936.

OBJECTIVE To determine whether plasma uric acid concentration in inland bearded dragons (Pogona vitticeps) was affected by recent ingestion of a meal of crickets.

PROCEDURES Food was withheld for 48 hours prior to experiments. Animals (6/group) were randomly assigned to receive a meal of crickets (equivalent to 1% of the animal’s body weight; 10 g/kg [4.5 g/lb]; treatment group) or have food withheld for an additional 48 hours (control group). Blood samples were collected for plasma uric acid measurement just before (time 0) and 4, 24, and 48 hours after feeding. Effects of feeding and time on the targeted measurement were assessed by repeated-measures ANOVA.

RESULTS Mean plasma uric acid concentration for the treatment group was significantly increased from the time 0 value (2.5 ± 1.5 mg/dL) 24 hours following meal ingestion (6.5 ± 1.2 mg/dL), but not at the 4-hour time point, and returned to the time 0 value by the 48-hour time point. No significant changes in plasma uric acid concentration were detected for the control group.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested food should be withheld for ≥ 48 hours prior to blood collection if inland bearded dragons are used to establish reference intervals for plasma uric acid concentration or if feasible when obtaining samples from these animals for clinical evaluation. Veterinarians should consider the time from last meal consumption when interpreting plasma uric acid concentration for this species and potentially other terrestrial insectivorous and omnivorous lizards.

• Land-based mammals excrete urea; water-based turtles produce ammonia or urea, and land-based reptiles and birds excrete uric acid
  
  • Uricotelic (UA) – Bearded dragons
  • Ureotelic (BUN) – Chinese soft shelled turtles, green sea turtles, Kemp’s ridley sea turtle, red-eared sliders, and American alligators
• BUN documented to increase in penguins and falcons after food consumption (snakes too)
• Treatment group as higher UA at 24hrs; UA at 4hr and 48hr were not different from baseline

Take home: Beardies had a significant increase in plasma UA at 24h after fed crickets equivalent to 1% BW

Question 89

A recent study evaluated the efficacy of oxfendazole in treating oxyurids in green iguanas.

When are oxyurids considered a problem?

What is oxfendazole?

How effective was it as treatment?

Answer 89

Kehoe, S., Divers, S., Mayer, J., Comoli, J., & Verocai, G. G. (2020). Efficacy of Single-Dose Oxfendazole to Treat Oxyurid Nematodiasis in the Green Iguana (Iguana iguana). Journal of Herpetological Medicine and Surgery, 30(3), 137-141.

Abstract: Seventeen healthy sub-adult green iguanas (Iguana iguana) naturally infected with oxyurid nematodes were treated to assess the anthelmintic efficacy of a single 25 mg/kg oral dose of oxfendazole. Pooled fecal samples were collected pre-treatment, then weekly for 4 wk post-treatment, and processed the same day via a quantitative double centrifugation technique using Sheather’s sugar flotation solution. Total oxyurid egg counts were determined and parasites identified to genus, Ozolaimus or Alaeuris, based on egg morphometry. Fecal egg count reduction (FECR) was then calculated for total oxyurids, total Ozolaimus spp., and total Alaeuris spp. separately for each time point post-treatment. Based on FECR, the single oral dose of oxfendazole was found to be 100% effective (100% FECR) at eliminating nematodes from the GI tract 4 wk post-treatment, without any obvious morbidity or mortality. Additionally, a lack of larvated eggs was observed in the feces as soon as 1 wk post-treatment, with all eggs appearing degenerate at 2 and 3 wk post-treatment. Therefore, the eggs being shed at 3 wk post-treatment were likely nonviable, indicating that oxfendazole was able to impact nematode reproduction prior to reaching 100% efficacy.

• Oxyurids considered benign in herbivorous lizards and chelonia; can cause disease when illness, stress, immune suppression
• Oxfendazole – metabolite of benzimadozole anthelmintics, fenbendazole/febantel biotransformed into oxfendazole
• Oxfendazole single dose resulted in
  
  • Decreases in EPG at all time points
  • FECR for total oxyurid eggs by 62%, 88%, 99.9%, and 100% by 8, 16, 21, and 28-d post-tx
  • Lack of larvated eggs by 1 week
  • All eggs appeared degenerate by 2-3 weeks. No adverse clinical signs

Take home: Singe dose 25mg/kg PO oxfendazole 100% effective of eradicating oxyurids in green iguana

Question 90

A recent study compared electrolyte solutions in dehydrated bearded dragons?

What was the affect of all three types?

What changes occurred with reptile ringers?

What is reptile ringers?

Answer 90

American Journal of Veterinary Research 81(5):437-441, 2020

Evaluation of subcutaneously administered electrolyte solutions in experimentally dehydrated inland bearded dragons (Pogonavitticeps)

Parkinson LA, Mans C. (reviewed by LPK)

Objective: To evaluate the effects of 3 electrolyte solutions administered SC to experimentally dehydrated inland bearded dragons (Pogona vitticeps).

Animals: 9 inland bearded dragons.

Procedures: In a randomized, complete crossover study, experimental dehydration was induced by means of furosemide (10 mg/kg, SC, q 12 h for 4 doses), and then lactated Ringer solution, Plasma-Lyte A, or reptile Ringer solution (RRS; 1:1 mixture of 5% dextrose solution and isotonic crystalloid solution) was administered SC in a single 50-mL/kg dose in 3 treatments sessions separated by a minimum of 14 days. Food and water were withheld during treatment sessions. Plasma biochemical values, PCV, blood total solids and lactate concentrations, and plasma osmolarity were measured prior to (baseline) and 4 and 24 hours after fluid administration.

Results: Administration of RRS resulted in severe hyperglycemia (mean ± SD plasma glucose concentration, 420 ± 62 mg/dL), compared with baseline values (190 ± 32 mg/dL), and this hyperglycemia persisted for at least 24 hours. It also resulted in significant reductions in plasma osmolarity and sodium and phosphorus concentrations, which were not observed after administration of the other 2 solutions. Administration of lactated Ringer solution caused no significant increase in blood lactate concentration.

Conclusions and clinical relevance: The changes in plasma glucose, sodium, and phosphorus concentrations and plasma osmolarity observed after SC administration of a single dose of RRS suggested this type of electrolyte solution should not be used for rehydration of bearded dragons. Rather, lactated Ringer solution or Plasma-Lyte A should be considered instead.

Key Points:

• Furosemide resulted in mean 5% body weight loss (dehydration)
• All 3 fluid types resulted in
• Lower TP and TS at 24 hours after administration (no difference between fluids)
• Lower P
• Reptile ringer’s solution (1:1 mix of 5% dextrose solution + isotonic crystalloid) resulted in:
• Severe hyperglycemia at 4 hours (vs. baseline)
• Continued hyperglycemia at 24 hours
• Reduced plasma osmolarity at 24h
• Reduced Na and P concentrations at 24h
• Plasmalyte A and LRS
• No differences in glucose, osmolarity, Na, P at 24h
• None resulted in increased lactate with any
• RRS not recommended for rehydration
• LRS or Plasmalyte recommended instead

Take home: Reptile ringers à severe hyperglycemia for >24hrs, use LRS or plasma-lyte

Question 91

A recent paper described a case of a teratoma in a bearded dragon.

What are teratomas?

how do they differ among taxa?

What tisue of origin do they arise from in reptiles?

Answer 91

Gandar, F., Paillusseau, C., Deflers, H., Marlier, D., Heckers, K. O., & Schilliger, L. (2020). Benign Ovarian Teratoma in a Central Bearded Dragon (Pogona vitticeps). Journal of Herpetological Medicine and Surgery, 30(2), 63-67.

Abstract:

A 6-yr-old female central bearded dragon (Pogona vitticeps) was examined for a 6 month history of increasing coelomic distention, dyspnea, dysorexia, and tenesmus. Complementary examinations revealed hyperuricemia, hyperphosphatemia, increased creatine kinase, and a heterogeneous polycystic mass with peripheral coelomic effusion. An exploratory coeliotomy revealed a mass at the anatomical location of the right ovary and follicular stasis of the left ovary; bilateral ovariectomy was performed. After anatomopathological and bacterial examination, the dragon was diagnosed with benign ovarian teratoma and secondary bacterial infection. The presence of yolk and remnants of the ovary with several cell types originating from different origins, which was confirmed by immunohistological examination, is consistent with ovarian teratoma lesions generally observed in other species.

Summary:

• 6yr F bearded dragon
  
  • 6 month history of increasing coelomic distention, dyspnea, dysorexia, and tenesmus
  • PE – lethargy, severe coelomic distention with impeded locomotion, irregular firm and large mass extending from sternum to hip
  • Rads - loss of contrast, large mass occupying majority of coelomic cavity, with reduction in volume of pulmonary field
  • US - heterogeneous, polycystic mass with mild coelomic effusion
  • Chem - hyperuricemia, hyperphosphatemia, hypercalcemia, and increased CK
  • Paramedian celiotomy 🡪 found ovarian mass, performed bilateral ovariectomy
    
    • Ovarian mass was >43% of body weight
  • Culture from mass – positive for salmonella
  • Treatment post-op – fluids, tramadol, enrofloxacin
  • Histo of mass - benign ovarian teratoma with secondary bacterial infection
  • Chem and RR normalized 10 days postop
• Teratomas
  
  • germ cell tumors composed of several cell types and originate from several germ layers
  • most common location - ovary
  • benign ovarian teratomas - composed of mature histologic structures originating from ectoderm, mesoderm, and endoderm
  • teratomas suspected to arise from germ cells originating in mature gonads
  • mammals and birds - teratomas uncommon and usually benign (
    
    • rare in reptiles – all reports have been ovarian in origin
    • benign and malignant ovarian teratomas described in red-eared sliders and green iguanas
    • benign ovarian teratomas described in whiptail lizards and Fiji banded iguana
    • teratomas in others organs described in amphibians, but not in reptiles
  • most of histologic reports of teratomas in reptiles mention stratified keratinized squamous epithelia, gland-like structures, and focal areas of muscle, cartilage, or osseous tissues
• immunohistology recommended to confirm nature of tissues
  
  • reptiles - vimentin, GFAP, and desmin do not represent antigen expression, cannot be used in reptiles
  • cytokeratin showed marked antigen expression (epidermis, glandular lumina) and smooth muscle fibers exhibited marked antigen expression for SMA

Question 92

What is a neoplastic differential for bloody urates?

Answer 92

Journal of Herpetological Medicine and Surgery 30(2): 81-73, 2020

Anaplastic Sarcoma and Sertoli Cell Tumor in a Central Bearded Dragon (Pogona vitticeps)

Matthew J. Williams, Hannah E. Wong, Simon L. Priestnall, Balazs Szladovits, Nadene Stapleton, Joanna Hedley (Reviewed by LPK)

Abstract:  A 5-yr-old male central bearded dragon (Pogona vitticeps) was presented for investigation of blood in the voided urates. A small cutaneous mass was detected in the gular region, but the clinical examination was otherwise unremarkable. Fecal parasitology was negative. Initially, further diagnostics were declined and antimicrobial treatment was initiated. At re-examination 1 month later, the gular mass had increased in size and an additional mass was detected within the coelomic cavity. Both masses were surgically excised and diagnosed by histopathology as a high-grade anaplastic sarcoma (gular mass), resembling a histiocytic sarcoma, and a Sertoli cell tumor (coelomic mass). Neither of these have been previously reported in the central bearded dragon. Twenty months post-surgery, the lizard remains well with no recurrence of clinical signs or evidence of tumor re-growth.

Key Points:

· Blood smear – marked toxicity and left shift

· Two soft tissue opacities on radiographs à excisional biopsies

o Mid coelomic mass: Sertoli cell tumor

o Gular mass: histiocytic sarcoma

· Pathology retrospective – neoplasia 6% of all saurian samples; 8.5% in lizards and 8.6% agamids (Hernandez et al., 2003; Garner et al., 2004)

o Integumentary (case anaplastic sarcoma) 3rd most common system (Christman et al., 2017)

o Sertoli cell tumors not previously reported

· Cutaneous histiocytic sarcoma found on extremities, good prognosis with sx

· Two concurrent neoplasms within the same animal is unusual; no connection in this case

Take home: Sertoli cell tumors in reptiles with blood in the urates (sx curative), anaplastic sarcomas differential for cutaneous masses (sx, good prognosis)

Question 93

Coccygeal vein venipuncture in leopard geckos carries was risk?

How can this be mitigated?

What other site can be used for sample collection?

Answer 93

The Journal of Herpetological Medicine and Surgery, Volume 30, No. 3, 2020 pp. 156–164

Determination of Leopard Gecko (Eublepharis macularius) Packed Cell Volume and Plasma Biochemistry Reference Intervals and Reference Values

Ophelie Cojean, ,Drm ́ed v ́et, IPSAV, Sarah Alberton, DMV, IPSAV, R ́emi Froment,Drm ́ed v ́et,DACVP (Clinical Pathology), Edouard Maccolini,Drm ́ed v ́et, IPSAV, DABVP (Avian), ClaireVergneau-Grosset,Drm ́ed v ́et, IPSAV, CES, DACZM – Reviewed by MSM

Abstract: Despite the popularity of leopard geckos (Eublepharis macularius) in the pet trade, packed-cell-volume (PCV) and biochemistry reference intervals are still lacking for these animals. The risk of inducing tail autotomy during venipuncture is of particular concern in this species. Blood samples were obtained from 26 healthy subadults (14 females and 12 males) from the ventral coccygeal vein or the cranial vena cava under general anesthesia with isoflurane. Plasma biochemistry panels were performed by a reference laboratory and PCV was measured. Reference intervals were established following the American Society for Veterinary Clinical Pathology guidelines. Reference values were established for parameters with less than 20 available results because of limited sample volumes. Results were computed using the Reference Value Advisor software. Venipuncture was performed safely, without tail autotomy, in all 26 individuals. No lymph contamination was detected macroscopically. Reference intervals were 21–40% for PCV, 33–394 umol/L for uric acid (0.5 to 6.6 mg/dL), 0–3,701 IU/L for creatine kinase, and 0.6–37.5 umol/L for bile acids. Reference values were established for the following parameters: 0.5–5.3 mmol/L for phosphorus (1.5–16.4 mg/dL), 24–80 g/L for total protein (2.4–8.0 g/dL), 3.5 to >9.25 mmol/L for total calcium in females (14 to >37 mg/dL), and 11–65 IU/L for aspartate aminotransferase. Biochemistry results in leopard geckos were similar to those reported in crested geckos (Rhacodactylus ciliatus).

Key Points:

· Leopard geckos are at risk of tail autotomy during venipucture of ventral coccygeal vein

· Animals were anesthetized and venipuncture was from the tail vein unless twitching tail movement persisted and then the cranial vena cava was used.

· No adverse effects or tail autotomy were observed.

· Differences in venipuncture sites (chelonian lymph dilution in subcarapacial sinus)

· Reptile chemistry sex differences

o Higher glucose, protein, albumin in males; higher calcium, phosphorus, ALT, AST, and WBC in females in panther chameleons

o Crested geckos – calcium, phosphorus, TP, albumin higher in females; higher PCV in males

o Basiliks – higher albumin and globulins in males

· Assessing the liver

o AST and bile acids are the best bet

· Folliculogenesis associated with increased calcium, phosphorus, TP, and albumin

· Plasma total calcium can also be used to assess renal function

o Renal diseases commonly associated with hyperphosphatemia and hypocalcemia

o Ca:P <1 is an early but nonspecific indicator of renal disease in green iguanas

o Hyperuricemia may be less sensitive than the Ca:P ratio

· Samples changes to chem

o Hemolysis – increased potassium, phosphorus, TP, and AST

o Lipemia – increase BA

Take Home: You can draw blood from the leopard gecko vein – anesthetize them first

References:

· Laube A, Pendl H, Clauss M, Altherr B, Hatt JM. 2016. Plasma biochemistry and hematology reference values of captive panther chameleons (Furcifer pardalis) with special emphasis on seasonality and gender differences. J Zoo Wildl Med, 47(3):743–753.

Question 94

A recent study evaluated the common histologic findings of helodermatids in captivity.

What are the two species of helodermatids? What are their scientific names?

What was the most common category of disease?

What were the most common causes of enterocolitis?

What other findings were commonly seen?

Answer 94

Journal of Zoo and Wildlife Medicine, 2021. 52(1): 166-175

RETROSPECTIVE REVIEW OF HISTOLOGIC FINDINGS IN CAPTIVE GILA MONSTERS (HELODERMA SUSPECTUM) AND BEADED LIZARDS (HELODERMA HORRIDUM)

Jessica M. Magnotti, DVM, MichaelM. Garner, DVM, Dipl ACVP, Scott J. Stahl, DVM, Dipl ABVP (Avian), Emily M. Corbin, DVM, Dipl ACVP, and Elise E.B. LaDouceur, DVM, Dipl ACVP

Abstract: A retrospective study was performed by reviewing all Heloderma spp. submissions to Northwest ZooPath from 1996 to 2019. Necropsy and biopsy specimens from 106 captive Gila monsters (Heloderma suspectum) and 49 captive beaded lizards (Heloderma horridum) were reviewed. Inflammatory diseases were the most frequently diagnosed condition in Heloderma spp., and were diagnosed in 72% of all animals examined, including 76% of Gila monsters and 63% of beaded lizards. The most common cause of inflammation was bacterial infection, which was present in 52% of all Heloderma spp. with inflammation. Enterocolitis was common in Gila monsters (20%) and beaded lizards (14%), but the underlying causes were different for each species. Cryptosporidium spp. was the most common cause of enterocolitis in Gila monsters (36%) but was not identified in beaded lizards. Amoebiasis was a common cause of enterocolitis in Gila monsters (27%) and was the most common cause of enterocolitis in beaded lizards (57%). Deposition diseases were diagnosed in 34% of all Heloderma spp. The most frequently diagnosed deposition disease in beaded lizards was urolithiasis-nephrolithiasis (12%). This disease was not diagnosed in Gila monsters. Deposition diseases that were common in Gila monsters and beaded lizards included hepatic lipidosis and renal gout. Neoplasia was diagnosed in 17% of all Heloderma spp., including 17% of Gila monsters and 18% of beaded lizards. The most common neoplasm of Heloderma spp. was renal adenocarcinoma, which was equally common in Gila monsters and beaded lizards. Less common diagnoses included degenerative diseases, trauma, nutritional disease, nonneoplastic proliferative disease, nondegenerative cardiovascular disease, and congenital malformation.

Key Points:

• Helodermatids (Gila monster and Beaded lizard) – venomous, carnivorous lizards native to the Americas
• Objective – describe spectrum of diseases diagnosed histologically in Heloderma spp.
• Amongst categories examined inflammatory diseases were most common followed by deposition diseases, neoplasia, degenerative disease, trauma, nutritional disease, non-neoplastic proliferative disease, cardiovascular disease, and congenital.
  
  • Inflammatory – most common cause of inflammation was bacterial infection (~50%) and resulted in bacteremia/sepsis in ~20% of cases.
    
    • Most common location – intestines. Entercolitis in 20% of Gila monstera commonly associated with Cryptosporidia spp. (~35%) or amoeba (~25%). Enterocolitis in beaded lizard most commonly associated with amoeba (no crypto seen) and in some cases spread systemically. Second most common cause of inflammation was coelomitis, most commonly from free yolk.
  • Deposition disease – Renal gout was most frequent cause in Gila monster and second most common cause in Beaded lizards
    
    • Gout most often occurred in the absence of other renal disease, suggesting that nonrenal causes of gout (e.g. dehydration) may be more substantial in the pathogenesis
  • Urolithiasis-nephrolithiasis most common deposition disease in beaded lizard (not found in Gila monsters). Hepatic lipidosis also common in both species
  • Neoplasia – Most common neoplasm was renal adenocarcinoma in both Gila and Beaded.
  • Degenerative disease – Most frequently diagnosed in in Heloderma spp. was chronic renal disease
• Epidemiologic data:
  
  • All animals with myocardial fibrosis were male.
  • Yolk coelomitis occurred exclusively in sexually mature or geriatric animals

Take home:

Inflammatory diseases secondary to bacterial infection most common. Enterocolitis secondary to Cryptosporidia (Gila) and amoeba (Gila and Beaded) common. Urolithisis-nephrolithsis common in beaded lizards (not found in Gila). In both species, renal gout, hepatic lipidosis, and renal adenocarcinoma also common.

Question 95

What is the recommended method for measuring albumin in bearded dragons?

Why?

Answer 95

Journal of Zoo and Wildlife Medicine 52(1): 253-258, 2021

COMPARISON OF PROTEIN ELECTROPHORESIS AND BIOCHEMICAL ANALYSIS FOR THE QUANTIFICATION OF PLASMA ALBUMIN IN HEALTHY BEARDED DRAGONS (POGONA VITTICEPS)

Jessica Comolli, DVM, Stephen Divers, BVetMed, Dipl ZooMed, Dipl ECZM, Dipl ACZM, FRCVS, Brad Lock, DVM, Dipl ACZM, and Melinda S. Camus, DVM, Dipl ACVP

Abstract: While electrophoresis is considered the standard method for evaluation of protein concentrations as a result of its direct measurement, albumin is often quantified with biochemical assays. Many laboratory-based chemistry analyzers and clinic-based point-of-care analyzers use the dye bromocresol green (BCG) for the quantitation of albumin. Several studies have shown that albumin concentrations obtained by the standard (BCG) dye-binding method are significantly different from those obtained by protein electrophoresis in avian species and chelonia. The goal of this study was to compare plasma albumin concentrations obtained by the BCG method with those derived from electrophoresis in bearded dragons (Pogona vitticeps). Thirty-six heparinized plasma samples were obtained from 13 clinically healthy male bearded dragons. Albumin was quantified by protein electrophoresis and by the BCG dye-binding method. The two methods were significantly different (P<0.0001, paired t-test; P<0.0001, Wilcoxon signed-rank test), with the BCG measurement always equal to or higher than the electrophoretic result. The measurements from both methods were significantly correlated (r=0.8634, P <0.0001), but concordance between the two techniques was poor. The Bland-Altman plot appeared to show a greater difference between the two measurements with lower albumin values and lesser difference with higher values. These results indicate that bearded dragon plasma albumin concentration measurements obtained by the BCG dye-binding method are unreliable when compared to those obtained with electrophoresis, suggesting that albumin should be measured by protein electrophoresis for health assessment in bearded dragons.

Key Points:

• Albumin maintains plasma colloid oncotic pressure and binding protein responsible for transport of substances; negative acute phase protein (decr. in concentration in response to inflammation)
• EPH – direct measurement of protein based on weight & charge; BCG for quantitation of albumin
  
  • BCG dye-binding method is unreliable when compared to EPH for avian species
• Three blood samples – initial, 4hr sample, and 24 hr sample; EPH performed at UMiami
  
  • No difference in albumin from baseline to post-prandial values
• BCG dye binds to albumin molecules, the intensity of dye = amount of albumin in the sample
• BCG plasma albumin was higher than EPH values in this study
  
  • differences between the two methods appeared to be greater with lower plasma EPH albumin values
  • BCG dye may cross react with a, b, and gamma globulins, leading to false elevations in plasma albumin
  • Reptile albumin levels tend to be lower than mammals
• Plasma preferred over serum for EPH in reptiles since fibrinogen is a major APP

Take home: EPH gold standard for albumin measurement; BCG had higher values should not be used in bearded dragons for albumin

Question 96

A recent study established a bearded dragon specific neurological exam.

Many of the traditionally tested reflexes were inconsistent in this species, but a new reflex was identified - what is that?

What are some potential causes of neurological disorders in bearded dragons?

What is the scientific name of the bearded dragon?

Answer 96

JAVMA 2022 260(9):1013-1023
Neurological examination in healthy adult inland bearded dragons (Pogona vitticeps)
Tarbert DK, Murthy VD, Guzman DS

Key Points:
* Causes of neurological disorders in bearded dragons include:
– Atadenovirus infection, listeriosis, hypocalcemia, lucibufagin toxicosis from fireflies, encephalopathy secondary to hypertension, and peripheral nerve sheath tumors
* Novel reflex - caudal thoracic extensor reflex was observed in all animals

Question 97

A recent paper investigated the effects of alfaxalone in bearded dragons.

What is the scientific name of the bearded dragon?

What dose was used?

What was the best route of administration?

Is this sufficient for surgery?

Were any side effects noted?

Answer 97

Use of alfaxalone in bearded dragons (Pogona vitticeps): optimizing pharmacodynamics and evaluating cardiogenic effects via echocardiography.
Webb JK, Keller KA, Chinnadurai SK, Kadotani S, Allender MC, Fries R.
Journal of the American Veterinary Medical Association. 2023;261(1):126-131.

Key Points:
- Novel alfaxalone formulation (with preservatives) given 15 mg/kg IV to bearded dragons had shortest time to maximum effect with predictable deep plane of sedation, loss of deep pain, jaw tone, purposeful movements, and righting reflex
– Not sufficient for surgical anesthesia at this dose
- Subclinical respiratory depression occurs and there is a small change in contractility (shown by increased end-systolic volume on echo) but no change in HR
- Other routes (IM, SQ, ICo) were less predictable in inducing deep sedation

Question 98

A recent study described the clinicopathologic findings and urolith composition for green iguanas.

What is the scientific name of the green iguana?

What was the most common urolith type? What other types were identified?

Were these uroliths visible radiographically?

How were these cases managed?

Were bacteria isolated from the urine of affected iguanas?

Answer 98

JAVMA 2022 260(10) 1216–1221
Clinicopathologic findings and urolith composition for green iguanas (Iguana iguana) with urolithiasis: 21 cases and 132 stones (1996–2020)

Key Points:
- 132 urolith submissions: All uroliths were composed of salts of uric acid. Ammonium acid urate (n = 12) and sodium acid urate (10) were specifically identified in a minority of cases, with the remaining 110 uroliths described as 100% salts of uric acid.
- Green iguanas with urolithiasis may not have clinical signs, or may have non specific signs
- All green iguanas in the present study had uroliths visible on standard radiographs.
- Green iguanas in this study most commonly had a single urolith.
- 15/21 underwent surgery for urolith removal, with 12 surviving at least until hospital discharge
- 4 iguanas had intraoperative cysto and urine culture - all were positive, klebsiella most common
- Recurrent urolithiasis was seen in 3 cases and surgery was again performed

Question 99

A recent study investigated the safety of IM doses of ketoprofen in the bearded dragon.

What is the scientific name of the bearded dragon?

Why would a nonselective COX-1 & -2 inhibitor be useful in reptiles?

How did the 2 mg/kg versus the 20 mg/kg doses perform?
- What lesions were seen?

Answer 99

Evaluation of the Safety of Multiple Intramuscular Doses of Ketoprofen in Bearded Dragons (Pogona vitticeps)
JHMS 2022 32(2) 123-129

Background:
- Cyclooxygenase (COX) 1 has been shown to increase significantly in inflamed ophidian skin and chelonian muscles.
- Nonselective COX-1 and COX-2 inhibitors, such as ketoprofen, could therefore reduce inflammation more effectively than preferential COX-2 inhibitors in reptiles

Takeaway:
* Based on the parameters evaluated in the present study, the administration of ketoprofen at 2 mg/kg IM diluted 1:10 in saline once daily for 14 days appeared to be safe in healthy adult bearded dragons.
* Conversely, a dose of 20 mg/kg IM q24h for 14 days caused muscular necrosis

Question 100

A recent study surveyed the feeding practices and supplement use of pet bearded dragons in the US and Canada.

What did the typical diet consist of?

What were the most common insects used?

What supplements were used? Is this supported by the literature?

Answer 100

JHMS 2022 32(3) 187-197
Survey of Feeding Practices and Supplement Use in Pet Inland Bearded Dragons (Pogona vitticeps) of the United States and Canada

Key Points:
- Data on wild bearded dragons suggests that bearded dragons are opportunistic predators that mostly eat plants
- However, the proportions of plant and insect material recommended for captive adult bearded dragons reported in literature vary between 50 and 90% plant material and between 10 and 50% animal material
- The most common diet consisted of 1–25% larval insects, 1–25% adult insects, and 51–75% plant material
- Approximately one half of the survey participants, especially the younger respondents, were feeding diets with 50% plant material and 50% insects
- Most common plant offered was berries, but largest proportions of plant material were typically leafy greens, followed by other vegetables
- owners younger than 18 yr of age were more likely to offer too many insects, mainly larval insects, and not enough plant material.
- Superworms and hornworms were the most common larval insects, and superworms have been shown to contain some of the highest percentages of fat compared with other larval insects
- Crickets were the most common nonlarval insect offered and has been shown to contain significantly less crude fat than the larval superworm but comparable amounts of fat to the hornworm
- Current literature does not recommend fruits in the diet
- The majority of owners provided calcium with vitamin D3, a finding that is consistent with the literature
– This recommendation is not evidence based for bearded dragons because the only study completed thus far on this topic indicated that oral supplementation of vitamin D3 was ineffective at increasing plasma calcidiol and calcitriol concentrations compared with 2 h of UVB exposure
- Currently, guidelines for calcium supplementation in bearded dragons remain vague
- Most owners reported gut loading, but info on what they were gut loading or for how long were not analyzed
- A large portion of respondents did not have water available in a bowl for their bearded dragons.
- The exact amount and frequency of food offered were not evaluated in this survey and might have provided important information on the total caloric intake

Question 101

A recent study investigated the pharmacokinetics of TMS in the green iguana.

What was the most commonly cultured organism at UGA in this species?

What is the benefit of adding in sulfamethoxazole?

What is the spectrum of sulfa drugs?

What dose was used?

Did IV or PO administration result in significant plasma levels?

Answer 101

JHMS 2022 32(3) 198-207
Pharmacokinetics of Trimethoprim-Sulfamethoxazole in the Green Iguana (Iguana iguana)

Background:
- Institutional antibigram at UGA showed that Pseudomonas was the MC organism cultured. Mostly gram negatives from reptiles. 83% of G+ and 53% of gram negative bacteria were sensitive to TMS; in vitro susceptibility to TMS (83%) was comparable to that of enrofloxacin and ceftazidime.
- Trimethoprim - often resistance alone, so sulfamethoxazole is added, ratio 1:5, bacteriostatic separately, bactericidal together
- Sulfas have high oral biovailability , rapidly absorbed, and penetrate CSF, ocular, prostate, pleural tissues/fluid etc.
- Spectrum of sulfas gets many G- and G+ bacteria, coccidia, and protozoal organisms - toxoplasma, some anaerobes and chlamydia

Take home message
- 30mg/kg TMS PO once daily does not reach adequate MIC breakpoint levels to be effective.
- IV admin: synergistic ratios of TMP:SMZ did not last past 4h in majority of iguanas, so IV use is impractical
- PO TMS maintains antibacterial pasma drug ratios longer than does IV TMS and may need to be dosed orally q12h
- TMS has lack of in vivo efficacy against anaerobes, inherent resistance of Psuedomonas and Enterococcus, and neutralized abx activity in abscessed or necrotic environments

Question 102

A recent study investigated the cytological characteristics of the oral cavity in the inland bearded dragon.

What is a common oral disease of managed lizards?

What samples were taken for this study?

Describe the histology of the healthy BD oral cavity.

Answer 102

JHMS 2022 32(3) 230-235
Cytological Characterization of the Oral Cavity of the Inland Bearded Dragon

Key Points:
- Periodontal disease and stomatitis are common in captive lizards, confirmed by cytology which helps ID bacterial, fungal or even viral agents
- Two sites - tongue and palate - were sampled and stained Diff Quick
- Samples from both tongue and palate were hypocellular, esp palate samples
– Mostly mature anucleated keratinized squamous cells, polygonal, pale cytoplasm
– Large to medium sized epithelial cells
- Sometimes goblet cells from tongue
- Cytological exam of oral mucosa in bearded dragons showed abundant presence of keratinized, nucleated or anucleated squamous cells. Anucleated cells less common vs nucleated cells. Intermediate cells 3rd MC cell type.
- Provides a baseline for cytology of oral mucosa in bearded dragons

Question 103

A recent paper described a technique to remove a marble foreign body from a bearded dragon.

What was that technique?

Answer 103

JHMS 2022 32(4) 253-258
Endoscope-Guided Marble Foreign Body Removal Technique in an Inland Bearded Dragon (Pogona vitticeps)

Key Points:
- Difficult to grasp a smooth spherical object like a marble with endoscopic forceps
- Red rubber catheter and luer lock syringe used to suction the marble
- The airtight interface between the wide end of the catheter and smooth marble surface was crucial to the successful outcome
- This technique is minimally invasive and involves equipment most vets have ready access.

Question 104

A recent paper described an epidermal cyst on the head of a leopard gecko.

What is the scientific name of the leopard gecko?

How did this animal present?

What were the histopathological findings?

How do these cysts form?

Answer 104

The Journal of Herpetological Medicine and Surgery, Volume 32, No. 4, 2022 pp. 259–261
Epidermal Cyst on the Head of a Leopard Gecko (Eublepharis macularius)
Mitsuhiro Ikeda, Hirotaka Kondo, Yuki Iwata, Naoto Tsunesumi, Miho Kameda, Daiki Hotta, Hisashi Shibuya

Key Points:
- Leopard gecko is crepuscular insectivorous lizard native to Pakistan, Afghanistan and India
– Iridophoroma common in Lemon Frost color morph of leopard gecko
- 6yr old female presented with raised spherical mass on head w/ focal area of ulceration and osteolysis of underlying skull
– Dermis expanded by well demarcated epidermal cyst filled with laminar keratin 🡪 benign encapsulated lesion
- Unreported trauma suspected as the cause (implantation of epidermis into dermis)

Take home: First description of epidermal cyst in lizard din managed care.

Question 105

A recent case study described the repair of a comminuted femur fracture in a komodo dragon.

What is the scientific name of the komodo dragon?

Why were locking plates used instead of traditional non-locking plates?

Answer 105

JHMS 2023 33(1) 11-17
Repair of a Comminuted Femur Fracture in a Komodo Dragon (Varanus komodoensis) Using a Double Plating Technique.
Kristin A. Coleman1 , Caleb C. Hudson1 , Joe Flanagan

Background
- Locking plates were chosen instead of traditional nonlocking bone plates to minimize disruption of the periosteum and periosteal blood supply, which bone healing is dependent on in reptiles (locking plates applied with locking screws minimize disruption of the periosteum b/c the screws lock into the bone plate and form an angle stable construct, rather than compressing the bone plate against the periosteal surface of the bone

Take home message
- Acute fracture management in Komodo dragons can include orthopedic techniques used in domestic small animals. This is the first report of a successful femur fracture stabilization using bone plate fixation in this species.

Question 106

A recent study investigated the use of disinfectants against isolates of Nannizziopsis guarroi.

What are the clinical signs and lesions associated with this disease?

Ophidiomyces, a related organism, is disinfected by what?

What disinfectants were most effective in removing N. guarroi?

Answer 106

Effectiveness of common disinfecting agents against isolates of Nannizziopsis guarroi.
Jourdan B, Hemby C, Allender MC, Levy I, Foltin E, Keller KA.
Journal of Herpetological Medicine and Surgery. 2023;33(1):40-4.

Key Points:
- Nannizziopsis guarroi - severe, often fatal, contagious dermatomycosis in bearded dragons, previously ‘yellow fungus disease’; unknown mode of transmission, infections linked to stress, overcrowding and substandard husbandry with breaches in cutaneous integrity
– CS: ulcerative, crusty skin lesions that can progress to deeper tissues and occasionally visceral dissemination
- Prolonged environmental persistence, cultured from env for prolonged period
- Single study on Ophidiomyces ophidiicola showed complete inhibition by household bleach and 70% ethanol with 409 also effective
– O.o has been shown resistant to chlorhexidine
- Disinfection of the environment and items in contact with lizards infected with Nannizziopsis guarroi by using 10% bleach for at least 2 min after cleaning biological material from the surface
– 3% bleach and 409 (QAC) show promise
– Virkon, Lysol (hydrogen peroxide), ethanol, novalsan (chlorhexidine) and ammonia cannot be recommended
– Ammonia appeared to support growth of the fungus

Question 107

A recent study characterized the annual reproductive cycles of male veiled chameleons and panther chameleons.

What is the scientific name of the veiled chameleon?

What is the scientific name of the panther chameleon?

What were their respective reproductive strategies?

What was the morphology like of the spermatozoa?

What is a proposed advantage of the observed speramtozoa clumping?

Answer 107

JHMS 2023 33(1):45-60
Characterizing the Annual Reproductive Cycles of Captive Male Veiled Chameleons (Chamaeleo calyptratus) and Panther Chameleons (Furcifer pardalis)
Perry SM, Camlic SR, Konsker I, Lierz M, Mitchell MA

Key Points:
- Veiled chameleons appear to follow a prenuptial reproductive strategy
– Testosterone elevated over a prolonged period of time, prior to peak semen production
- Panther chameleons appear to follow a postnuptial reproductive strategy
– Semen collection was highest well after the apparent peak in testosterone
- Veiled and panther chameleon spermatozoa morphology was similar to other lizards
– In both species, a true primary spermatozoa defect was detected: a macrocephalic head
– The remaining spermatozoa defects appeared to be secondary in nature
– The most common defect observed was distal droplets
– May be result of spermatozoa being discharged from the epididymides with electroejaculation
– Proportion of distal droplets varied by month and may have been associated with the time the spermatozoa were in the epididymis
- Spermatozoa clumping may be a reproductive strategy to enhance male’s ability to copulate
– Decreased amount of time needed for copulation to occur
– Precopulatory ejaculation in the cloaca = reduced copulation time and increased success

Question 108

A recent study evaluated the causes of mortality of caiman lizards.

What is the scientific name of the caiman lizard?

What was the leading cause of death?

What was the second most common cause of death?

What comorbidities were identified?

What changes to the management of this species should be made based on this study?

Answer 108

Journal of Zoo and Wildlife Medicine 2023:53(4), 714-721.
CAUSES OF MORTALITY AND COMORBIDITIES IN CAIMAN LIZARDS (DRACAENA GUIANENSIS) AT SIX ZOOLOGICAL INSTITUTIONS.
Cerreta, A. J., Landolfi, J. A., Griffioen, J. A., Woc-Colburn, M., Kubiski, S. V., & O’Connor, M. R.

Key Points:
- Infectious disease was the most common cause of mortality in adult lizards (8/20; 40%) with amoebiasis and bacterial etiologies being overrepresented.
- Demise due to traumatic/accidental injury was the second most common cause of death in adult lizards (3/20;15%) and included blunt force trauma or suspected drowning
- The most common comorbidities or other incidental findings identified during necropsy included trematode parasitism (15/32; 46.9%), arteriosclerosis (11/32; 34.4%), and adrenocortical hyperplasia (6/32; 18.8%).
- Infectious disease caused by amoeba/protozoa (enterocolitis) and bacterial infection (yolk ceolomitis), followed by accident/trauma are the most common causes of death in Caiman lizards. They are also susceptible to degenerative diseases and comorbidities are most commonly infectious/parasitic in origin, including multicentric trematode infection.
– Aquatic snails are the IH and may infect managed Caiman lizards
– Exhibit design should account for risk of trauma and drowning; management should include screening for infectious diseases

Question 109

A recent paper described mast cell neoplasia in the green iguana.

What is the scientific name of the green iguana?

Mast cells are not found in which reptile group?

What stains are used to identify mast cells?

What lesions did these iguanas present with?

Answer 109

JZWM 2023 53(4):864-869
MAST CELL NEOPLASIA IN THE GREEN IGUANA, IGUANA IGUANA
Kleinschmidt LM, Reavill DR, Kiupel M, Hoppes SM, Strunk A, Garner MM

Key Points:
- Mast cells are found in multiple tissues in all reptilian subgroups except Tuatara
– Special stains used to identify mast cells: toluidine blue (T-blue) or Giemsa stain
– MCT reported in two tortoises, three snakes, and one gecko
- Case series describes mast cell neoplasms in 10 green iguanas
- Raised skin/oral mass-like lesions, may be multicentric w/ potential extensive local invasion
- All reported cases had cutaneous lesions
– Lesions associated w/ the oral cavity in 1/3 of cases and head in 1/3 of cases
– Lesions associated w/ skin of the trunk in 1/3 cases
– One case had a lesion on a limb
– In 6 of 10 cases w/ MCT of the face or oral cavity, lesions were focal
– In four cases w/ trunk lesions, a multicentric distribution was noted
– In one case, peripheral blood mastocytosis was documented
- Surgical treatment was attempted in 8 of 10 cases
 7 of 10 surgical biopsies had incomplete excision based on histology
- c-kit mutations may not be a driver of oncogenesis in MCT in iguanas

Question 110

A recent study investigated the risk factors associated with metastatic soft tissue mineralization in zoo-housed komodo dragons.

What is the scientific name of the komodo dragon?

What are common causes of mortality for this species?

What husbandry parameters were associated with an increase in metastatic mineralization?

What disease states were associated with an increase in metastatic mineralization?
- What is the suspected pathophysiology here?

Answer 110

Characterizing Husbandry Risk Factors Associated with Metastatic Soft Tissue Mineralization in Zoo-Housed Komodo Dragons (Varanus komodoensis) in the United States
Dawn Zimmerman, Jennifer H. Yu, Willem Schaftenaar, Laura Debnar, Drury Reavill, Michael M. Garner, Mark A. Mitchell
Journal of Herpetological Medicine and Surgery 32 (1), 73-83

Key Points:
- KD in captivity tend to live shorter lives than those in the wild
- Common KD causes of mortality - vascular mineralization, follicle rupture and yolk embolism, spinal trauma, renal dse +/- gout, paralytic ileus
– Metastatic tissue mineralization common in females with follicle rupture. Occurs in multiple tissues (consistent with systemic, not localized process). May be assd with hyperCa in folliculogenesis
– Metastatic mineralization primarily occurs ex situ, so husbandry/diet likely to play a role
- Zoos that approximated rather than measured humidity were 12.0 times as likely to have a history of mineralization in their Komodo dragons
- Study compares husbandry and other risk factors across multiple institutions housing Komodos and uses univariate and multivariate analyses to assess significance of each
- Metastatic mineralization was the most common lesion assd with mortality in komodo dragons. It was significantly associated with females, especially those with yolk coelomitis or embolism

Question 111

A recent study described metastatic mineralization in spot-tailed earless lizards.

What is the scientific name of this species?

Metastatic mineralization is associated with what abnormal biochemistry?
- What lesions are typically seen as a result?

Describe vitamin D metabolism in reptiles from the skin to the kidney.

What was the proposed etiology of the mineralization in these cases?

Answer 111

JZWM 2023 54(1):175-184
Metastatic Mineralization In A Zoologic Collection Of Spot-Tailed Earless Lizards (Holbrookia spp.)
Cannizzo SA, Reppert A, Ward A, et al

Background:
- Low Ca, high P diets associated with nutritional secondary hyperparathyroidism in reptiles
- Dystrophic mineralization associated with inflammation, degeneration, or tissue damage
- Metastatic mineralization results from hyper-Ca, hyper-P, or abnormal Ca metabolism
– Common locations: blood vessels, heart muscle, renal tubules, and lung tissue
– In larger animals, metastatic mineralization can be seen on radiographs
– Ddx: renal disease, hyper-Ca of malignancy, hyperparathyroidism, hypervitaminosis D
- Reptile skin contains provitamin D3 (7-dehydrocholester-ol) -> UVB rays -> previtamin D3
– Previtamin D3 is thermoisomerized into vitamin D3 (cholecalciferol)
– In liver, cholecalciferol is hydroxylated to calcifediol (25-hydroxyvitamin D)
– In kidney, calcifediol converted to biologically active 1,25-dihydroxyvitamin D3 (calcitriol)

Key Points:
- Case series describes mortalities of an entire zoologic collection of earless lizards
– Attributed to metastatic mineralization secondary to hypervitaminosis D
– Dietary-induced hypervitaminosis D considered most likely cause of mineralization in these lizards
– Highlights a potential species or family sensitivity to dietary D3
– Consider relying on UVB exposure alone or use caution when supplementing with D3
- Mineralization of blood vessels could have predisposed to infections or sepsis, inflammatory processes (e.g., yolk coelomitis), and the hemorrhage that was seen grossly on necropsy
- Size of spot-tailed lizards precluded measuring P, total Ca, PTH, or D3 concentrations
– Pooled liver samples submitted for D3 quantification in lieu of serum measurements
– Wide range of hepatic D3 concentrations
- Highlights importance of performing regular quality control checks on all nutritional supplements
– If regular quality control is cost prohibitive, aliquots can be frozen for future testing
– Aliquots can be combined for testing, with follow-up testing of specific samples as needed

Question 112

A recent study described the biological variability of bearded dragon hematology.

When are population reference intervals recommended?

When are subject based reference intervals recommended?

What was recommended for bearded dragons?

Answer 112

SHORT-TERM BIOLOGICAL VARIABILITY OF HEMATOLOGY PARAMETERS IN THE BEARDED DRAGON (POGONA VITTICEPS)
Megan E. Colburn, DVM, Amy N. Schnelle, DVM, MS, DACVP, Yvonne K. Wong, DVM, Emily M. Whitmore, DVM, Jennifer D. Reilly, DVM, Laura A. Adamovicz, DVM, PhD, Krista A. Keller, DVM, DACZM, and Matthew C. Allender, DVM, MS, PhD, DACZM
Journal of Zoo and Wildlife Medicine 53(2): 284–290, 2022

Key Points:
- Biological variation is the normal physiologic variability in clinical pathology parameters attributed to multiple intrinsic and extrinsic factors – it is assess by serially sampling individuals over time
- The different between serial samples within an individual and between individuals is used to determine the reference change value (RCV) ad index of individuality
– If high intraindividual variation but low interindividual variation (high index of individuality) – ok to use population based RIs
– If low intraindividual variation but high interindividual variation (low index of individuality) – population based RIs are less useful
- Population based RI may be appropriate to analyze PCV, TS, and WBC counts (regardless of methodology) in bearded dragons based on the index of individuality