Xenarthra Flashcards
Unique anatomy of xenarthrans?
Unique anatomy of northern tamanduas? Which features are not found in anteaters?
RADIOGRAPHIC ANATOMY OF THE FORELIMB IN THE NORTHERN TAMANDUA (TAMANDUA MEXICANA)
Lozada-Gallegos AR, Muñoz-García CI, Villanueva-García C, Rocha-Martínez N, Ovando-Fuentes D, Trejo-Salas MB, Reyes-Delgado F, Rendón-Franco E.
Journal of Zoo and Wildlife Medicine. 2020 Jun;51(2):265-74.
Background:
Myrmecophagidae = ant (myrm) + eater (phag)
Contains giant anteater, southern tamandua, northern tamandua
Unique anatomy of xenarthrans
Synsacrum = fused ilium + ischium + lumbar vertebra
Homodont, open rooted dentition, no enamel
Xenarthrous processes in spine
Very low metabolism
Key Points:
Unique anatomy of northern tamanduas (*not found in anteaters):
Hamatus process* = elongated acromion process
Supraglenoid foramen = fusion of supraglenoid tubercle and cranial scapula
Looks like a hole in the scapula
Divided humoral capitulum
Ulna is longer than radius
Sesamoid bone in carpus*
Plantigrade locomotion on carpus* (anteater = digitigrade)
Take Home Message: Tamanduas are built for climbing and plantigrade walking with shoulder and carpus adaptations.
Unique genital anatomy of aardvarks?
What glands can be easily confused with testicles?
ANATOMY, HISTOLOGY, AND DIAGNOSTIC IMAGING OF THE REPRODUCTIVE TRACT OF MALE AARDVARK (ORYCTEROPUS AFER).
Wojick KB, Langan JN, Terio KA, Righton A, Drees R.
J Zoo Wildl Med. 2018 Sep;49(3):648-655.
Background:
Aardvark fun facts:
Belong to Afrotheria (with elephants, hyraxes, manatees, elephant shrews, and tenrecs)
Have elodont (continuously growing) teeth that lack enamel
Large scent glands at the base of the penis are often mistaken for testicles in aardvarks
Can develop obstruction and abscessation
Key Points:
The large round structures at the base of the penis are indeed scent glands.
The testicles are in the caudal abdominal cavity and can move through the inguinal ring to the SC space
Aardvarks lack a scrotum
Aardvark accessory sex glands: seminal vesicles, prostate gland, bulbourtethral glands
Ultrasound provided good images of reproductive tract
CT scans had too much artifact from the pelvis to provide good images
Histology of the organs was similar to other mammals
Conclusions: Aardvark testicles are intraabdominal; don’t confuse the scent glands for testicles.
Giant armadillos ax with butorphanol-dexmedetomidine-midaz +/- ketamine did what vs other spp?
How did adding ketamine affect anesthesia?
ANESTHESIA AND SURGERY PROTOCOLS FOR INTRAABDOMINAL TRANSMITTER PLACEMENT IN FOUR SPECIES OF WILD ARMADILLO
Kluyber D, Lopez RP, Massocato G, Attias N, Desbiez AL.
Journal of Zoo and Wildlife Medicine. 2020 Nov;51(3):514-26.
Giant armadillos anesthetized with butorphanol-dexmedetomidine-midazolam +/- ketamine had:
Longer induction and immobilization (compared to six banded and southern naked tailed armadillos)
Prolonged apnea (n=1)
No difference in recovery time
Adding ketamine lengthened time with surgical plane of anesthesia
Rapid, smooth induction in all species.
Conclusions: Butorphanol-dexmedetomidine-midazolam with or without ketamine provides effective anesthesia in armadillos, but giant armadillos had longer induction and immobilization times.
What were some causes of mortality in wild sloths that were moved to human care?
Were clinical signs observed with Leishmania in sloths?
What is a sloth specific tick?
What viral dz has been associated with mortality in captive sloths?
IDLY INFECTED: A REVIEW OF INFECTIOUS AGENTS IN POPULATIONS OF TWO-AND THREE-TOED SLOTHS (CHOLOEPUS SPECIES AND BRADYPUS SPECIES).
Smith LH, Ruple A.
Journal of Zoo and Wildlife Medicine. 2021 Jan;51(4):789-98.
Background:
Common sloth species:
Hoffman’s two-toed sloth (Choloepus hoffmanni)
Linnaeus’s two-toed sloth (Choloepus didactylus)
Correlation between rates of Leishmaniasis in sloths and people (sloths are potential reservoir)
Key Points:
Bacterial disease were not a major cause of morbidity (ranged from Bordetella to E. coli)
After wild capture and move to captivity, some sloths died from Histoplasma capsulatum and Paracoccidiodes
Signs: anorexia, cachexia, granulomatous enteritis
Typical signs of ringworm (alopecia, crusts) from Microsporum gypsum and M. canis
Several species of Leishmania found in sloths with no clinical signs
Sloth-specific tick = Amblyomma varium
Fatal canine distemper virus infection in captive sloths
Signs: Oculonasal discharge, anorexia, diarrhea, death
Eosinophilic intranuclear and intracytoplasmic inclusion bodies
Conclusions: Sloths have a variety of infectious diseases and may serve as a reservoir to leishmaniasis.
What clinical signs were observed in a giant anteater and a hairy armadillo with vitamin D toxicosis?
HYPERVITAMINOSIS D IN A GIANT ANTEATER (MYRMECOPHAGA TRIDACTYLA) AND A LARGE HAIRY ARMADILLO (CHAETOPHRACTUS VILLOSUS) RECEIVING A COMMERCIAL INSECTIVORE DIET
Georgina C. Cole, Adam D. Naylor, Emma Hurst, Simon J. Girling, Richard J. Mellanby
J. of Zoo and Wildlife Medicine, 51(1):245-248 (2020).
Background:
Vitamin D3 is produced in the skin when UVB light transforms 7-dehydrocholesterol
Vitamin D can also be obtained from the diet at vitamin D2 or D3
Vitamin D2 and D3 are converted to 25(OH)D in the liver, then 1,25(OH)D in the kidney
Total and ionized calcium levels with hypervitaminosis D because 25(OH)D increases intestinal absorption of Ca and P, renal reabsorption of Ca, and bone mobilization of Ca.
Clinical signs of hypervitaminosis D: lethargy, anorexia, vomiting, constipation, polyuria, polydypsia, weakness, hypotonia, hyporeflexia
Sequelae of chronic hypercalcemia: pancreatitis, gastric ulceration, azotemia, renal failure, arrhythmias, hypertension
Hypervitaminosis D can be caused by high dietary intake (food, vitamin D ointment, some rodenticides)
Cases: A giant anteater and a hairy armadillo developed lethargy, anorexia, vomiting, and abdominal discomfort
Hypervitaminosis D in serum levels, hypercalcemia in giant anteater
Diet changed from Mazuri Termant insectivore gruel to homemade diet
Their clinical signs and hypervitaminosis D (and hypercalcemia) levels resolved after a diet change.
Another armadillos fed this diet and euthanized for other reasons had hypercalcemia, nephritis, and metastatic calcification of kidneys, GI, and cardiovascular system
Hypercalcemia and soft tissue mineralization from hypervitaminosis D (and hypervitaminosis A) has been reported in tamandua fed diets with similar levels
Conclusions: Hypervitaminosis D can cause gastrointestinal signs in giant anteaters and hairy armadillos.
Urinalyis findings in healthy Linnaeus’ sloths?
RENAL EVALUATION IN CHOLOEPUS SPECIES
Black PA, Keller DL, Burton MS, Bissell H.
Journal of Zoo and Wildlife Medicine. 2020 Jan;50(4):983-7.
Background:
Sloth urinate only once every 3 to 8 days and can lose more than 30% of body weight when they urinate
Urinary disease is a significant cause of morbidity and mortality in captive sloths in North America
Urethritis, cystitis, nephritis, renal and cystic calculi, UTIs, neoplasia.
Key Points:
Ultrasound was most helpful for imaging urinary system (rads obstructed by GI)
Urinalysis findings in healthy Linnaeus’ sloths:
Epithelial cells
Proteinuria
Crystalluria (ammonium magnesium phosphate > amorphous phosphate > amorphous urate
Bacteriuria
Pyuria (seen in the absence of bacteriuria)
Hematuria
UP:Cr ratios higher in Hoffmann’s, but similar to domestic animals
Conclusions: Healthy sloths have epithelial cells, proteinuria, crystalluria on urinalysis.
Discuss vaccine recommendations for sloths based on paper about serologic response to CDV.
SEROLOGIC RESPONSE TO CANINE DISTEMPER VACCINATION IN CAPTIVE LINNAEUS’S TWO-TOED SLOTHS (CHOLOEPUS DIDACTYLUS) AFTER A FATAL CANINE DISTEMPER VIRUS OUTBREAK
Sheldon JD, Cushing AC, Wilkes RP, Anis E, Dubovi EJ
Journal of Zoo and Wildlife Medicine. 2017 Dec;48(4):1250-3.
Cases: 6 adult two-toed sloths developed canine distemper infections
Signs: Lethargy, anorexia, ocular and nasal discharge, oral/nasal ulcerations and diarrhea
5 out of 6 were euthanized
Histo: Intracytoplasmic inclusion bodies throughout the GI, liver, spleen and lungs
Key Points:
Vaccination protocol in this study: 1 mL canarypox-vectored CDV + 3 wk booster
Seroconversion in 75% of sloths
Conclusions: Vaccinate your sloths for canine distemper virus with a recombinant vaccine.
Pros of dried blood spot cards for measurement of vit D3 in serum of Hoffman’s two-toed sloths.
Higgins, J. L., Scanlon, L. M., Makowski, A. J., & Childs-Sanford, S. E. (2020). Evaluation of 25-hydroxyvitamin d in hoffmann’s two-toed sloths (choloepus hoffmanni) using dried blood spots analyzed by liquid chromatography–tandem mass spectrometry. Journal of Zoo and Wildlife Medicine, 50(4), 751-757.
- Risks of vit D imbalances are high – Lack of knowledge of vit D requirements, frequent supplementation of diets with vit D, housing indoors or at northern latitudes where cutaneous synthesis of vit D cannot occur.
- Sloths have a low metabolic rate, may be especially prone to vit D toxicity and soft tissue mineralization with vit D supplementation. Hypovitaminosis D also of concern since they may rely on cutaneous synthesis but are often housed indoors.
- Measurement of vit D in DBS samples from animals has not previously been reported. Advantages to using this method, small amt of blood needed, easily stored and transported, useful application for field studies.
- Takeaway: DBS techniques require small sample volumes and simplify storage and transport of samples. Good agreement between vit D3 in serum and DBS samples in Hoffman’s two-toed sloths.
Describe the unique biology and anatomy of xenarthrans.
What order do these animals belong to?
What are the families of the three groups?
What are some of the unique characteristics of this group?
What about their vertebrate & scapula?
What cardiovascular adaptations do they have?
What is unique about their teeth?
What is unique about sloth stomachs?
What type of placentation do they have?
TAXONOMY
Xenarthra is a superorder
- Armadillos - Order Cingulata
- Families Dasypodidae & Chlamyphoridae
- Anteaters & Sloths - Order Pilosa
- Anteaters - Suborder Vermilingua
- Families Myrmecophagidae & Cyclopedidae
- Sloths - Suborder Folivora
- Families Bradypodidae & Choelopodidae
- Anteaters - Suborder Vermilingua
BIOLOGY
- 31 species of armadillos, sloths, and anteaters
- Restricted to the New World
- Giant anteaters are ground dwellers
- Lesser anteaters are predominantly arboreal, but also move on ground
- Silky anteaters are strictly arboreal and nocturnal
- Species specific biologic info including weight, conservation status, reproductive period, gestation length, offspring, etc. in Tables 39-1 and 39-2
UNIQUE ANATOMY AND PHYSIOLOGY
- Additional xenarthrous joints of lumbar vertebrae
- Fusion of ischium to anterior caudal vertebrae
- Secondary scapular spine
- Extensive retia mirabile in the limbs
- Paired post renal vena cava
- Ossified sternal ribs
- Significantly reduced, homodont continuously growing teeth that lack enamel
- Canniform teeth present in sloths
- Armadillos: carapace of ossified dermal tissue covered by epidermal scales
- Sloths have specialized large stomachs of several chambers
- Ferments rough plant material
- Only go to the ground 1/week to defecate
- Basal rates of metabolism around 40-60% of those expected for body mass
- Fairly low ambient temperature
Xenartha = armadillos, sloths, anteaters
- Multiple bony variations – additional lumbar vertebral joints, fusion of ischium to caudal vertebra, secondary scapular spinous process, ossified sternal ribs
- CV – prominent rete mirabile in limbs and paired venae cavae in posterior abdomen
- Homodont teeth continue to grow and lack enamel
- Anteaters and tamandua lack teeth
- Armadillo – hardened carapace of dense ossified dermal tissue with overlying epidermal scales
- Placentation varies: anteaters and armadillos = villous and hemochorial; sloths =endotheliochorial
- Sloth digestive tract complex with multiple chambers
- Anteater – long tongue bifurcated anterior to attachment at sternum; glottis is at base of neck
Describe the husbandry of xenarthrans.
What is their ideal enclosure set up? What are the specifics for armadillos, sloths, and anteaters?
What are the dietary strategies of armadillos?
What about sloths? Which genus is more difficult to keep? Why?
What are the natural diets of anteaters?
What are some of the nutritional deficiencies in anteaters in managed care? How do those animals present?
SPECIAL HOUSING REQUIREMENTS
- Need shelter if ambient temp drops below 15 degree Celsius
- Armadillos: soft substrate such as soil, mulch or shavings so they can dig
- Wall footers should go at least 1 m underground to keep them in
- Need hiding places if housed with others
- Injured armadillos may be cannibalized
- Sloths: Large spaces to climb
- Floors should have semi soft substrate in case of fall
- Bradypus (three toed) are difficult to maintain in captivity
- Anteaters: natural flooring
- Tamandua, Cyclopes require numerous branches to climb
FEEDING
- Armadillo: carnivores, omnivores, insectivores
- Sloths: rich in fibers, and contains low levels of energy and soluble carbohydrates
- Bradypus are strongly attached to specific tree species, so captive diet is difficult
-
Choloepus (two toed) has a more varied diet
- Eat insects, birds, and small reptiles as well as plants
- Food should be cut lengthwise to facilitate handling
- Sloths may not drink water
- May respond well to transfaunation during episodes of suspected dysbiosis
- Anteaters: forage almost exclusively on ants and termites , different proportions of insects by species
- Giant anteaters: ingest seeds, beetle larvae, and bees
- Lesser anteaters consume beetles and seeds
- Diets may be based on a semi liquid mix
- All anteater species should be supplemented with Vitamin K and taurine
- Vitamin K deficiency may lead to hematuria and prolonged bleeding
- Taurine deficiency has been associated with DCM
Fowler 7 Ch 49 - Feeding and Nutrition of Anteaters
Superorder Xenarthra: 2 orders
- Cingulata (armadillos)
- Pilosa (anteaters and sloths)
Unique Traits:
- Secondary articulations (xenarthrales) – between lumbar vertebrae & spinal column
- Fused pelvic bones
- Low metabolic rate
- Variable body temp. to conserve energy
Unique Dietary Needs:
- Folivores – 3 toed sloth (Bradypodidae)
- Omnivore-generalists – 2 toed sloth (Choloepus sp)
- Specialized carnivores – giant anteater (Myrmecophaga tridactyla) & tamanduas (Tamandua tetradactyla, T. mexicana)
- Armadillos feed on ants and termites and others are omnivores.
Anteaters:
- Giant anteaters (Myrmecophaga tridactyla) Diet: 96% ants, 4% termites
- Tamandua – Diet of ants, termites, but prefer reproductive and worker castes
- Tongues – 60cm reach, high mobility = 150 times/min, can consume 30,000 ants/day
- Silky anteaters- nocturnal live in trees. Consume ants, termites, beetles.
- Termite nutritional analysis- varies according to caste (class) – soldiers low in fat, reproductive forms higher in fat. (Table 49-1)
Nutritional disorders:
Vitamin A
- Rear limb paresis, flaccid paralysis, hyperostosis of vertebrae
- Reported in Tamandua Mexicana
- Associated with Vit A toxicosis or excess Vit D and/or calcium
Vitamin K
- Deficiency (will cause hemorrhagic problems)
- Especially when animal has been on antibiotics must supplement vitamin K
Taurine
- deficiency -> dilated cardiomyopathy
- whole blood <300nmol/ml (normal 300-600)
- plasma <60nmol/ml (normal 60-120)
- may be assoc. with feeding canine diets (no taurine supplemented), and young tamunduas on milk replacer
- feed cat food to prevent this problem
Loose stool
- animals fed high grain/lactose products
- hi fiber requirement
Constipation
- Caused by lack of fiber or tongue problem
Diabetes
- may be assoc. with high starch diet
Commercial insectivore diet makes feeding anteaters easier, but not perfect.
- Less than 10% starch
- Better alternative to primat/feline chows
- Tamandua have 42% lower metabolic rate than expected. 449 kJ/kg/day
- Adding a souce of indigestible fiber (chitin or cellulose) to the new gruels or insectivore pellets may be beneficial to manage this lower metabolism.
Tables comparing different diets (Table 49-2 and Box 49-1)
Describe the restraint and anesthesia of xenarthrans.
How are each group manually restrained?
What physiologic considerations need to be made prior to anesthesia?
Where are common venipuncture sites?
What drugs are commonly used?
What are some issues with using inhalants for induction?
What are some issues with alpha 2 use? When is it recommended they be removed?
RESTRAINT AND HANDLING
Physical restraint
- Armadillos: rec wearing heavy gloves to avoid scratches
- Agile and will try to wriggle out of grip
- May relax if pressure is placed on lateral carapace
- Sloths: two toed sloths are more aggressive than three-toed and need to be handled cautiously
- Beware of claws of caniniform premolar teeth
- Tamandua and Cyclopes may be held with leather gloves or by placing them in a cloth bag
- Myrmecophaga may be restrained using sticks or nets, but may need to bandage claw to avoid injury
Chemical restraint
- Low metabolic rates and low and varying body temps, need to perform immobilization in a controlled environment
- Intubation of anteaters and armadillos may be challenging to impossible
- Prolonged diastema in a very narrow mouth
- Intubation of Dasypus may be possible with a stylet
- Dosages listed in Table 39-3
- Dasypus seem less sensitive to ketamine and require a higher dose
- Premedication with atropine prevents intensified salivation with ketamine
- Induction chambers of masks may be a problem bc armadillos can hold their breath for several minutes
DIAGNOSTICS
- Armadillos
- Rectal temp in armadillos is variable and may be difficult to interpret
- Collect blood from ventral tail vein
- Alternatively the medial saphenous
- Sloths
- Blood collection via brachial vein
- Maximum blood volume should not exceed 0.5% body weight
- Anteaters
- Blood collected from central coccygeal vein (Cyclopes and Tamandua) or the cephalic and medial or lateral saphenous veins (Myrmecophaga )
- Hematology and serum biochem values are in tables 39-4, 39-5
West Ch 34 - Edentata (Xenarthra)
Perianesthetic preparations
- Edentates are often characterized as heterothermic or incompletely homeothermic with a wide range of normal body temperatures
- Sloths have a normal body temperature range of 24-40 C
- Body temperatures may be influenced by ambient temperatures
- Captures should be avoided during cold or inclement weather conditions
- Fasting smaller species for 4-6 hours is appropriate and large species should be fasted for 12-24 hours
Physical restraint
- Most armadillos, anteaters, and sloths can be manually restrained, though gloves and/or nets can be helpful
- 2 toed sloths can move very quickly when harassed and will bite
Induction
- All edentates can be effectively immobilized with ketamine or tiletamine in combination with benzodiazepines or alpha 2’s
- Can also use inhalant induction with smaller species, though induction can be prolonged due to breath holding
- In one study in lesser anteaters increased ketamine doses seemed to increase relaxation, but also caused severe bradycardia
- Darting in anteaters has been associated with severe agitation, longer induction, and incomplete immobilization–hand injection is preferred when possible
- Can use etorphine in combination with diazepam and atropine for giant anteaters–no cardiac or respiratory depression was noted in one study
Maintenance
- Maintained on gas inhalant, often alpha 2 will be antagonized at this point because they cause bradycardia and bradyarrhythmias
- Armadillo and sloth can be easily intubated, whereas anteaters are not routinely intubated
- Tracheotomy supplies should be available for emergency situations
- Armadillos can hold their breath and seem to tolerate hypoxemia better than other mammals
Support
- Blood pressure can be measured indirectly, since IV and intra-arterial access sites are challenging to locate in edentates
- Catheterization may require a venous cutdown
- Access sites include the femoral and cephalic veins for all edentates
- Sloths also have cubital veins and vertebral veins that can be sued fro blood collection
- Anteaters and armadillos also have jugular or ventral tail veins
- IO fluids administration can also be used in emergent situations
- It has been reported that armadillos will spontaneously recover from V fib
Recovery and complications
- Severe cardiovascular abnormalities can occur when alpha agonists are used for immobilization–can reverse as needed
- Post recovery excitement and self trauma can occur if the animals are confined after recovery. Animals often pace excessively and injure claws and feet by pawing at shift doors
What are some of the common diseases of armadillos?
Prolonged antibiotics may alter intestinal microflora resulting in what deficiencies?
What is the most significant bacteria of armadillos? Where is it localized? What are the typical clinical signs? What are the two forms of this disease?
Armadillos
- Many health problems related to poor husbandry and inadequate or imbalanced nutrition
- Injuries to tail and feet
- Prolonged abx tx may reduced intestinal microflora that synthesize menaquinones🡪
- Hypovitaminosis K and spontaneous bleeding
- Should be accompanied with supplementation
- Obesity
- Subclinical nephritis, wild caught animals may be more susceptible to nephrotoxic drugs and renal diseases
- Mycobacterium leprae (Dasypus)
- North American species don’t tend to have many parasites, but should be a concern for imports
- Dirofilaria immitis has been a cause of death in a 3- banded armadillo
- Protozoa: Sarcocystis, Leishmania naiffi, Trypanosoma cruzi, Toxoplasma gondii, and Entamoeba histolytica
- Fleas, ticks, and mites
Zoo Path
- Leprosy (Mycobacterium leprae) – endemic in armadillos (primarily Daysypus novemcinctus) in SE US and seen in Central and South America 🡪valuable experimental model for disease and reservoir for zoonotic transmission
- Genetically based resistance w single nucleotide polymorphisms in toll-like receptors, similar to humans
- Thrives at cooler temperatures (armadillos core BT sig. lower than most mammals)
- M. leprae localizes in peripheral nerves and reticuloendothelial system🡪 intermittent, low level bacteremia 🡪 widespread dissemination
- Armadillos rarely clinically ill until late disease
- CS: plantar ulcers (diminished neural sensitivity), skin erosions around eyes, nose, footpad
- Cutaneous armoring makes challenging to find other lesions
- Histo: Granulomatous response in organs and skin. Destruction of nerves, particular Schwann cells
- Peripheral nerves infected early and widely
- Typical Ridley-Jopling responses: “tuberculoid” to three stages of “borderline” reaction (tuberculoid, intermediate, borderline lepromatous) to “lepomatous”
- Tuberculoid leprosy – intense cell-mediate immunity with small lesions, papules and plaques
- Lepromatous leprosy more common in armadillos– dissemination of bacteria due to no effective immune reaction 🡪 granulomas. Higher number of bacilli
Describe the common diseases of sloths.
What systems are commonly affected?
What parasite is acutely fatal?
Sloths
- Traumatic injuries -> fractures are difficult to repair
- Bradypus are highly susceptible to stress and prone to suffer dehydration and malnutrition, then leads to immune suppression
- Respiratory infections lead to pulmonary edema and death in more than 95% of cases
- Commensal arthropods are commonly found on the skin of wild sloths
- Treatment of endoparasites is not recommended unless the patient is showing clinical signs
- Toxoplasmosis may be acute and lethal
Metabolic:
- Addison’s disease (hypoadrenocorticism) in a Hoffmann’s two-toed sloth (Kline et al. 2015) and giant anteater
- Histo: marked adrenal cortical atrophy; IN inclusions (unable to detect viral etiology)
Describe the common diseases of anteaters.
DCM is thought to be due to what nutritional deficiency? What are the gross and histologic lesions?
Tamanduas with hyperostosis present with what clinical signs? This is thought to be due to what vitamin deficiencies?
What viruses have been reported in anteaters?
What are some important causes of enteritis in anteaters?
Anteaters
- Trauma, spontaneous abortion
- Dilatory cardiomyopathy caused by taurine deficiency
- Diarrhea common in diets with insufficient chitin or fiber
- Protozoa: Coccidia, Giardia, and Amoeba
- Metronidazole and azythromicin indicated for tx
- Managed anteaters - DCM reported, may be related to taurine deficiency
- Cardiomyopathies in multiple species, most notably anteaters, hedgehogs and rock hyrax
- Nutritional factors suggested – potential taurine deficiency, but not confirmed
- Gross: hypertrophy, hepatomegaly, pulmonary edema and congestion, hydrothorax
- Histo: myocardial fibrosis and edema; LV myocardial degeneration, necrosis, atrophy, hypertrophy, myofiber disarray
- Cardiomyopathies in multiple species, most notably anteaters, hedgehogs and rock hyrax
- Tamandua - hyperostosis of vertebrae (may eventually fuse entire vertebral column) - paresis, bladder distention, reduced mobility, riding kyphosis; may mineralize soft tissue structures as well
- Hyperostosis – progressive disease in captive collared (lesser) and northern tamandua
- CS: paresis, bladder distention, reduced mobility, rigid kyphosis
- Coalescing osteophytes 🡪 fusion of vertebral column
- Leads to mineralization of CV system, splenic capsule, kidney, etc.
- May be associated with low Vitamin A and Vitamin D in diet
- Hypovitaminosis K - anteaters, armadillos - spontaneous hemorrhage at mucocutaneous jxn, hematuria - managed diets (vs termites/ants) may be deficient
- Influenza A (Orthomyxoviridae, H1N1) - giant anteater colony - nasal discharge, inappetence, lethargy
- Canine distemper virus (Paramyxoviridae - Morbillivirus) - giant anteaters - congestion, lethargy, diarrhea, anorexia, ataxia, hyperkeratosis - eosinophilic nuclear AND cytoplasmic inclusions
- Enteritis - Salmonella, Shigella, Campylobacter, E. coli, Yersinia pseudotuberculosis - associated w poor husbandry, contaminated feed, immunocompromised (stress, transport)
How does the forelimb anatomy of northern tamandua differ from anteaters?
RADIOGRAPHIC ANATOMY OF THE FORELIMB IN THE NORTHERN TAMANDUA (TAMANDUA MEXICANA)
Lozada-Gallegos AR, Muñoz-García CI, Villanueva-García C, Rocha-Martínez N, Ovando-Fuentes D, Trejo-Salas MB, Reyes-Delgado F, Rendón-Franco E.
Journal of Zoo and Wildlife Medicine. 2020 Jun;51(2):265-74.
Northern tamanduas have a hamatus process (elongated acromion), sesamoid bone in the carpus.
Like anteaters, also have a supraglenoid foramen, ulna longer than radius, divied humoral capitulum.
Northern tamanduas have plantigrade locomotion on the carpus. Anteaters digitigrade.
A recent paper described rabies in Southern Tamandua.
What is the scientific name of this species?
Rabies has been documented in what other xenarthran species?
How did this animal present?
How did the other anteaters in the collection respond to vaccination? How does this guide preventative medicine?
JZWM 2022 53(4) 797-800
RABIES DIAGNOSIS AND RESPONSE TO VACCINATION IN SOUTHERN TAMANDUA (TAMANDUA TETRADACTYLA)
Abstract: Rabies has rarely been described in Xenarthra, and rabies vaccine response has not been documented. A southern tamandua (Tamandua tetradactyla) presented with nonspecific clinical signs and was euthanatized. Subsequently, immunohistochemistry and RT-PCR confirmed a rabies diagnosis. Following these tests, a group of eight captive tamanduas were vaccinated with a killed rabies vaccine, and titers were measured at the time of vaccination and 23 d later. One animal had day 0 titers suggestive of previous vaccination or exposure. All animals had detectable neutralizing rabies virus antibody titers after vaccination, but one animal failed to meet the World Organization for Animal Health’s definition for adequate vaccination (0.5 IU/ml), and two other animals had low antibody titers (0.56 and 0.6 IU/ml). Rabies should be considered as a possible cause of illness in tamanduas, and rabies vaccination may be a useful preventative measure when anthropic interaction through medical care or ambassador roles is occurring
Intro
- Rabies has rarely been reported in Xenarthra, with only armadillos (Dasypus novemcinctus) having documented infection
M&M
- Tamandua presented with nonspecific clinical signs of lethargy, hypersalivation, urinary incontinence, and hyporexia, without known trauma, bite wounds, or exposure to local wildlife
- Necropsy and IHC consistent with rabies
- The other 8 tamanduas in the collection were vaccinated for rabies and titers were measure
Results and discussion
- 7 out of 8 had negative titers at the time of vaccination
- Postvaccination titers were increased in all animals but remained below what is required from the OIE in one animal
- First confirmatory diagnosis of rabies in a tamandua
- Mammals with low body temperature (like tamanduas) are assumed to be less susceptible to rabies virus infections; however, this case adds to the body of evidence that they are not immune
- The vaccination protocol used in this case series resulted in detectable neutralizing antibodies without adverse effects.
- Multiple doses may be required
Describe canine distemper infection in xenarthrans.
Name three xenarthran species that have developed natural infection due to CDV.
- Which of these developed pneumonia?
- Which of these developed neurological signs?
- Which of these developed hyperkeratosis?
CDV was initially reported in 2006 in a family of zoo-housed giant anteaters (Myrmecophaga tridactyla)
pulmonary congestion, ataxia, diarrhea, lethargy, and anorexia
* Gross and histopathologic lesions included pneumonia with eosinophilic intranuclear and intracytoplasmic inclusions, foot pad hyperkeratosis, and ulcerative glossitis
In 2016, a group of eight Linnaeus’s two-toed sloths (Choloepus didactylus) were housed in a quarantine building along with procyonids and small primates at a private zoo in eastern Tennessee
* 6 sloths presented with oculonasal discharge, oral ulcerations, and diarrhea
* Clinical pathological findings included anemia, increased immature neutrophils, lymphopenia, thrombocytopenia, elevated blood urea nitrogen (BUN), and hypocalcemia
* Despite empirical and supportive treatments, five sloths died while one fully recovered.
* Necropsies revealed severe ulceration and inflammation of the upper gastrointestinal tract, widespread hepatic necrosis, lymphoid depletion, and bronchointerstitial pneumonia with eosinophilic intracytoplasmic and intranuclear inclusion bodies in multiple organs
* CDV was confirmed using immunohistochemistry, virus isolation, and PCR.
* Sequencing revealed that strain was identical to a new lineage, America 4, affecting domestic dogs and wildlife in Tennessee
* Interestingly, there were no central nervous system clinical signs or gross and histopathologic lesions
Shortly after the sloths became ill, three kinkajous (Potos flavus) in the same building presented with similar clinical signs, died, and were also diagnosed with CDV without neurologic signs or lesions
* The first report of kinkajous with natural, nonvaccine-induced canine distemper
* Based on viral identification of the America 4 strain, it was hypothesized that the infection likely originated from a raccoon or domestic dog on grounds.
* Following the outbreak, seven other sloths at the same zoo were examined and administered a recombinant CDV on days 0 and 21
* Subsequent blood sampling revealed seroconversion in three of four sloths reevaluated.
* No adverse reactions or subsequent infections occurred
* Since then, all sloths and kinkajous at this zoo have been vaccinated using recombinant distemper vaccines without issues, and this was the first report of vaccinating xenarthrans for CDV
A 1-year-old southern tamandua (Tamandua tetradactyla) in human care in midwestern Brazil
* Presented with neurologic signs, including hypersalivation, seizures, and paresis
* Primary histopathologic lesions were located in the central nervous system, unlike the previous report in sloths
All of these CDV reports in xenarthrans have been in human care; thus the prevalence in free-ranging population is currently unknown. The inconsistency of neurological involvement is interesting and may indicate more rapid death in those cases in which the CNS is spared
