Lizard Diseases Flashcards
1
Q
What coelomic cavities do lizards have?
A
- Single pleuroperitoneal cavity
- Monitors - post-pulmonary septum
- Tegus - post-hepatic septum
2
Q
GI system of lizards
A
- Depends on diet
- long with 1 cecum and large colon in herbivores
- Short in carnivorous species
- Venom glands
- Helodermatid lizards (Gila monster, bearded lizards) - along the lower jaw
- lack musculature to inject venom immediately - must chew venom into flesh of victim (only used in defense)
- Helodermatid lizards (Gila monster, bearded lizards) - along the lower jaw
- Tongue
- pojective and prehensive in Chameleon
3
Q
Describe the respiratory system of lizards
A
- Trachea - incomplete tracheal rings
- Larynx - similar to birds
- Lungs:
- Cranial part - respiratory
- Caudal part - avascular, airsac like
- unicameral - geckos, skinss
- Paucicameral - iguanas, chameleons, agamids
- Multicameral - monitor lizards
4
Q
Describe the renal system of lizards?
A
- A ureotelic organism generally excretes excess nitrogen as urea
- Urea is less toxic and needs less water for excretion
- Uricotelic organism excretes either uric acid or its salts
- Uric acid is the least toxic and require less water in comparison to urea and ammonia
5
Q
How are lizards sexed?
A
- Most males have prominent bilateral bulges at the ventral tail base where the hemipenes are located
- Some are sexually dimoorphic
- male iguanas - large dewlap, taller dorsal spines, larger opercular scales, large and well-developed femoral pores
6
Q
What are the risks of handling lizards
A
- Bite
- scratch with toenails
- Whip tail
7
Q
Where can venipuncture be done on lizards
A
- Ventral coccygeal
- jugular
8
Q
Unique cells on CBC?
A
- Heterophils
- Azurophil - behaves like monocyte
9
Q
How can lizards be imaged?
A
- Radiographs
- small patients - use dental radiographs
- At least 2 views - orthogonal
- horizontal beam!
- Ultrasound
- need a lot of gel and alcohol between scales to get a good image
- CT-scan
- extremely useful in reptiles
- MRI
10
Q
Where can IM injections be given in lizards
A
- Avoid tail and rear limbs because of First pass effect
- Forelimb (Triceps or Biceps)
- insert needle between scales
- draw back and inject as you normally would
11
Q
Where can SQ injections be given in lizards
A
- Absorption of fluids and medications variable
- No need to tent skin
- Location - Lateral body wall or inguinal space
- insert needle parallel to body wall in between scales
12
Q
What other routes for medication administration are there for lizards
A
- Intracoelomic - NOT recommended
- Oral
- IV - ventral coccygeal
- Intraosseous - distal femur, proximal tibia
- Cloacal route
13
Q
What are common non-infectious diseases of lizards
A
- Hypovitaminosis D
- Ca Deficiency
- MBD
- Low Humidity
- Dysecdysis
- Urolithiasis
- Sand impaction
- Cloacal Prolapse
- Egg binding/Dystocia
- Stomatitis
- Tail necrosis
14
Q
What is Hypvitaminosis D in lizards
A
- Vit D required through dietary intake or synthesis in skin via UV
- Necessary for intestinal absorption of Ca
- Hypovit D ⇢ Ca deficiency = Metabolic bone disease
15
Q
What are the clinical syndromes with Ca deficiency
A
- Nutritional secondary hyperparathyroidism (dietary and husbandry induced MBD)
- Renal secondary hyperparathyroidism (dietary and husbandry induced MBD)
- Osteoporosis
- Osteomalacia (adults)
- Rickets (young) - or fibrous osteodystrophy (excessive bone resorption and secondary fibrosis
- Hypocalcemia
- Systemic calcium deficiency
16
Q
What are the clinical signs/PE findings of MBD
A
- Clinical Signs:
- Lethargy, reluctance to move
- poor appetite or anorexia
- weight loss or poor weight gain
- poor truncal lift
- ileus - GI impactions
- PE:
- Pliable mandible or maxilla
- swollen bones (fibrous osteodystrophy)
- Pathologic fractures
- Muscle twitching, tremors
- Less common:
- kyphosis, lordosis, scoliosis ⇢ occasionally rear limb paralysis
- Pliable mandible or maxilla
17
Q
How is MBD diagnosed?
A
- History: poor diet, no UVB exposure
- Clinical signs
- PE
- Radiographs/CT
- Decreased bone density, cortical thinning, fibrous osteodystrophy, fractures, widened ends of long bones, swelling at costochondral junctions
- Plasma Ca and P levels
- common for tCa to be normal
- iCa - often low, but lack reference ranges
18
Q
How is MBD treated
A
- Improve husbandry and environmental conditions
- optimize temperature, humidity, and UVB
- Provide high quality diet (calcium content)
- Force feeding (type depends on natural diet)
- Calcium supplementation
19
Q
What are the clinical consequences of inappropriate humidity
A
- Respiratory problems
- Dehydration - kidney disease in iguanas and chameleons
- Decreased reproduction
- lower life expectancy
20
Q
What is Dysecdysis?
A
- Abnormal shedding of the outer layer of skin
- Typically a sign of an underlying problem
- Common:
- digital constriction and loss of toes/toenails
- Tail constriction
21
Q
What is ecydsis?
A
- Normal process:
- Renewal phase - lymphatic fluid collects between old and new skin
- skin appears dull, marking become less distinct, spectacles appear opaque or milky blue
- Skin take on shiny appearance and reptile begins to shed
- particularly susceptible to trauma, infection, and toxin exposure
- Renewal phase - lymphatic fluid collects between old and new skin
- Length of shedding is affected by age and nutritional status
- Lizards often shed piecemeal
- geckos often ingest patches of shed skin, so it may not be observed in the environment
22
Q
Why does urolithiasis occur in lizards
A
most often a consequence of low humidity and chronic dehyrdration
23
Q
What is sand impaction in lizards
A
- Common in captive bearded dragons and geckos
- Contributing factor: ileus from low Ca/humidity
- Dx - radiographs, CT
- Tx:
- remove source
- correct calcium and hydration
- soaking and/or enemas
24
Q
What is Cloacal prolapse in reptiles
A
- What can prolapse
- Cloaca
- hemipenes
- bladder
- oviduct
- colon
- Secondary to an underlying problem
- Endoparasitism, tumors, Ca deficiency, urolithiasis, fecal impaction, egg binding, pre follicular stasis
- Try to identify the involved anatomical structure
- Lubricate and replace
- Amputate necrotic tissue - Know what it is!
25
Q
What reproductive tract diseases affect female reptiles?
A
- Egg binding / dystocia
- Follicular stasis
- Etiology: poor diet, low humidity, poor cage design (light, shelter, substrate)
- Dx - radiographs/CT/ultrasound
- Tx - correct husbandry, surgery
26
Q
What is stomatitis in lizards
A
- Scabbing and necross of gingiva
- Often secondary to systemic disease
- Dx:
- bloodwork
- radiographs/CT
- cytology and culture and sensitivity
- Tx:
- systemic antibiotics/antifungals
- topical meds
- analgesia
- surgical debridement as indicated
27
Q
What is tail necrosis in lizards
A
- necrosis of distal limb appendages ins common
- Causes:
- low humidity
- low temperature
- avascular necrosis
- sepsis
- Allow tissue to declare themselves!
- Treat any systemic disease that is present
28
Q
What infectious diseases are common in lizards
A
- Agamid adenovirus 1
- Encephalitozoon pogonae
- GI Parasites
- Oxyurid nematodes
- Isospora amphiboluri
- Cryptosporidium varanii
- Flagellates
- Fungal diseases:
- Nannizziopsis guarroi
- metarhizium spp.
- Purpureocillium lilacinus
- Candida albicans
- Fusarium spp
29
Q
What is Agamid Adenovirus 1
A
- Atadenovirus genera
- Affects bearded dragons most commonly
- Often afflicted with comorbidities
- Juveniles > adults
- Clinical signs:
- range from mild ill thrift to severe enterohepatic and neurologic signs
- enterohepatic - diarrhea, weakness, anorexia
- Neurologic - head tilt, circling, opisthotonos
- Death
- range from mild ill thrift to severe enterohepatic and neurologic signs
- Dx:
- Choanal-cloacal swab PCR
- Serology - low sensitivity
- Post mortem - karyomegalic, basophilic, intranuclear adenoviral inclusions and necrosis (especially in liver)
- Inclusion locations: hepatocytes, enterocytes, esophageal epithelium, myocardium, endocardium, lung, renal tubular epithelium, brain glial and epithelial cells, pancreas
- Other: EM, in situ hybridization, next gen sequencing
30
Q
What is Encephalitozoon pogonae
A
- Microsporidial parasite
- Develops primarily in macrophages within foci of granulomatous inflammation of different organs
- liver, heart, adrenal glands, ovaries, joints
- Transmission: horizontal, transovarial
- Dx: liver biopsy
- Still very little known about the disease
31
Q
What are the common GI parsites of lizards
A
- Oxyurid nematodes (pinworms)
- very common
- pathogenicity uncertain - suspected commensals
- left untreated unless clinical
- Fenbendazole most commonly prescribed
-
Isospora amphiboluri (coccidian parasite)
- Very common
- variable pathogenicity
- most commonly a problem in juveniles - poor doers, mortality
- Challenging to treat - toltrazuril, ponazuril
- Dx: modified sheather’s sugar floatation
-
Cryptosporidium varanii
- most common in leopard geckos
- Anorexia, progressive weight loss, coelomic swelling
- High morbidity and mortality
- Tx: paromomycin
- Flagellates
- common
- low pahtogenicity
31
Q
What are the common GI parsites of lizards
A
- Oxyurid nematodes (pinworms)
- very common
- pathogenicity uncertain - suspected commensals
- left untreated unless clinical
- Fenbendazole most commonly prescribed
-
Isospora amphiboluri (coccidian parasite)
- Very common
- variable pathogenicity
- most commonly a problem in juveniles - poor doers, mortality
- Challenging to treat - toltrazuril, ponazuril
- Dx: modified sheather’s sugar floatation
-
Cryptosporidium varanii
- most common in leopard geckos
- Anorexia, progressive weight loss, coelomic swelling
- High morbidity and mortality
- Tx: paromomycin
- Flagellates
- common
- low pahtogenicity
32
Q
What fungal disease affect lizards
A
-
Nannizziopsis guarroi
- Fungal dermatitis
- “Chryosporium anamorph of Nannizziopsis vriesii (CANV)”
- “yellow skin disease” “yellow fungal disease”
- Highly contagious
- Potential for systemic disease
- Diagnosis:
- skin biopsy
- PCR and sequencing
- Tx - challenging
- Voriconazole
-
Metarhizium spp
- M. granulomatis, M viride
- common in chameleons
- Clinical signs; tongue necrosis, dermatitis
-
Purpureocillium lilacinus
- causes pneumonia in a variety of lizard species
- Candida albicans
- Fusarium spp
