Management of Dental Disease in Aardvarks (Orycteropus afer) and Potential Use of Cone-Beam Computed Tomography.

Oral disease involving teeth is a common cause of morbidity in aardvarks (Orycteropus afer) under managed care. Cases can be challenging due to the species' unique skull and dental anatomy and limited veterinary literature. A retrospective evaluation was performed on dental examinations in nine aardvarks housed at a single zoological institution in the United States between 1995 and 2021. The prevalence of dental disease in this population was 88%, with most cases categorized as mild (4/8). Clinical signs were only seen in three cases. Facial swelling prior to surgery was the most common clinical sign (3/8). Dental pathology was more common in the mandibular teeth (27/38) compared to the maxillary teeth (11/38). Dental abnormalities found upon intraoral examination included the presence of dental points (7/8), crown elongation (3/8), purulent material within the oral cavity (4/8), loose teeth (2/8), periodontal pockets (2/8), and oronasal fistula (1/8). Three patients required dental extractions with a lateral buccostomy approach. Diagnostic imaging was performed in most cases (7/8), with two cases undergoing cone-beam computed tomography (CBCT) to characterize dental pathology that was difficult to fully evaluate with standard radiography. Tomographic findings are described in both cases. CBCT was found to be a helpful tool for diagnosing and characterizing dental disease in aardvarks.

PRESUMPTIVE CONGENITAL HYPOTHYROIDISM IN RED PANDAS (AILURUS FULGENS FULGENS) FROM FOUR SUCCESSIVE LITTERS.

High neonatal mortality among red pandas (Ailurus fulgens) challenges the long-term sustainability of the Species Survival Plan population. Congenital hypothyroidism (CH) is a rare condition in domestic animals, typically due to an inherited genetic defect. Nongoitrous CH was presumptively diagnosed in 75% (n = 6/8) of red panda neonates from four successive litters, with a common sire and two closely related dams. Antemortem diagnosis of CH was made in three cubs (n = 3/6) based on elevated thyroid stimulating hormone and decreased free thyroxine and total thyroxine levels. Affected cubs also had suggestive clinical signs, which included delayed growth with cretinous dwarf appearance, atonic bladder, delayed gastrointestinal motility, hypercholesterolemia, and hypocalcemia. With sodium levothyroxine therapy, two of the three cubs developed into normal adult red pandas in terms of body size, appearance, and behavior. On necropsy cubs (n = 4) were small with varying degrees of cretin dwarf appearance and hypoplastic thyroids with reduced to no colloid in follicles. These cases demonstrate the importance of collecting thyroid tissue, (or proximal trachea/larynx if gross visualization not possible), in neonates for histopathology. Further investigation into the role of thyroid disease in neonatal red panda mortality is warranted.

AN EVALUATION OF INFRARED THERMOGRAPHY FOR DETECTION OF BUMBLEFOOT (PODODERMATITIS) IN PENGUINS.

The objective of this study was to evaluate infrared thermography as a noninvasive screening tool for detection of pododermatitis during the developing and active stages of disease in three species of penguins: king penguin (Aptenodytes patagonicus) , macaroni penguin (Eudyptes chrysolophus), and rockhopper penguin (Eudyptes chrysocome). In total, 67 penguins were examined every 3 mo over a 15-mo period. At each exam, bumblefoot lesions were characterized and measured, and a timed series of thermal images were collected over a 4-min period. Three different methods were compared for analysis of thermograms. Feet with active lesions that compromise the surface of the foot were compared to feet with inactive lesions and no lesions. The hypothesis was that feet with active lesions would have warmer surface temperatures than the other conditions. Analysis of the data showed that although feet with active bumblefoot lesions are warmer than feet with inactive or no lesions, the variability seen in each individual penguin from one exam day to the next and the overlap seen between temperatures from each condition made thermal imaging an unreliable tool for detection of bumblefoot in the species studied.

Malignant melanoma in the penguin: characterization of the clinical, histologic, and immunohistochemical features of malignant melanoma in 10 individuals from three species of penguin.

Malignant melanomas are aggressive neoplasms that are relatively common in penguins compared to other avian species. In this study, the clinical and pathologic characteristics of melanocytic neoplasms in five macaroni (Eudyptes chrysolophus), three rock hopper (Eudyptes chrysocome), and two Humboldt (Spheniscus humboldti) penguins are described. Tumors most commonly occurred in the skin of the foot or hock, and were seen in the subcutaneous muscle, especially near the beak/oral cavity. Gross lesions were usually heavily pigmented, becoming raised and ulcerated over time. Humboldt penguins had a unique presentation, forming variably pigmented, cornified lesions in the inguinal area. Original case materials were obtained from all but two cases, and were assessed to define the characteristics of malignancy, evaluate four immunohistochemical markers for melanoma, and look for factors useful to informing prognosis and clinical decisions. Diagnosis was made histologically, based on morphologic features and pigmentation. Though not necessary for diagnosis, PNL-2 was found to be a useful immunohistochemical marker. HMB-45 showed unreliable positive labelling and S-100, Melan-A and Ki67 were not useful. Several factors were associated with prognosis, including gross surface dimension, mitotic index, depth of neoplastic cell invasion, and degree of surface ulceration. Metastatic spread occurred to the liver, lung, adrenal gland, brain, and bone; all lesions showed positive labelling to PNL-2. The average survival after diagnosis was 7 mo, though complete surgical excision of tumors less than 2.0 cm was curative in two cases and radiation therapy prolonged survival in one penguin. The underlying pathogenesis associated with the high prevalence of melanocytic neoplasms in captive penguins could not be identified. Three different molecular methods were performed to look for viral particles and results were negative. Advanced age is the most probable associated risk factor; ultraviolet light and chlorine exposure, viral induction, and genetic predisposition were ruled out or considered unlikely.

Skunk musk causes methemoglobin and Heinz body formation in vitro.

BACKGROUND: A captive Red Panda developed a regenerative anemia with Heinz bodies after being sprayed by a skunk. A definite cause-and-effect relationship between skunk musk and oxidative erythrocyte damage has not been reported, but it was suspected in one reported case of a dog with Heinz body hemolytic anemia. OBJECTIVE: The objective was to determine whether skunk musk induces oxidative HGB damage in vitro. METHODS: Plasma and RBC were harvested from heparinized blood of 3 dogs, 3 cats, and a Red Panda. Skunk musk was solubilized in ethanol and mixed with plasma from each species to make stock solutions of 4% musk and 4% ethanol. Aliquots of RBC were resuspended in autologous stock solutions and solvent controls to yield musk concentrations of 0%, 0.04%, and 0.4% (by volume). Aliquots were incubated at 37°C for 4-72 hours and assessed for oxidative damage by visual inspection, optical absorbance spectroscopy, transmission electron microscopy, and light microscopy after Wright and vital New Methylene Blue staining. RESULTS: Dose-dependent brown color and absorption changes characteristic of methemoglobin were present by 4 hours and increased over 24 hours (Red Panda) and 72 hours (dog and cat). Similarly, there were time-dependent (all species) and dose-dependent (dog and cat) increases in the number of Heinz bodies, which were present by 4 hours and numerous by 24 hours. CONCLUSIONS: In vitro, skunk musk causes Heinz body and methemoglobin formation in canine, feline, and Red Panda RBC, supporting the clinical association between Heinz body hemolytic anemia and skunk spray exposure.

Application of Elephant TB STAT-PAK assay and MAPIA (multi-antigen print immunoassay) for detection of tuberculosis and monitoring of treatment in black rhinoceros (Diceros bicornis).

Many wildlife species including rhinos are susceptible to infection with Mycobacterium tuberculosis or M. bovis. Antemortem diagnostic testing in large exotic hoof stock species has been limited by challenges associated with test administration, sample collection, and interpretation. Hence, a simple, rapid, blood-based test is needed. Two confirmed M. tuberculosis-infected black rhinoceros and one exposed suspect were evaluated for antibody responses using a lateral-flow rapid test (ElephantTB STAT-PAK) and multi-antigen print immunoassay (MAPIA). All three animals were seropositive by both tests. MAPIA detected antibodies to ESAT-6, CFP10, and MPB83 antigens. When the rhinos were treated with antitubercular therapeutics, their antibody responses gradually declined. One rhinoceros died approximately 9 mo after initiation of treatment and showed an increase in antibody titer shortly before death. The other two rhinoceros, which were treated for 1 and 2 yr, respectively, had no clinical signs or positive culture for M. tuberculosis at the time of necropsy performed 2 or 6 yr later for unrelated reasons. The antibody levels in these rhinos continued to be significantly decreased. The findings suggest that the ElephantTB STAT-PAK and MAPIA may be useful tools to detect M. tuberculosis infection and monitor treatment in black rhinoceros.

Ovarian dysgerminomas in two mountain chicken frogs (Leptodactylus fallax).

This report describes the gross, histologic, and immunohistochemical features of ovarian dysgerminomas in two adult female mountain chicken frogs (Leptodactylusfallax) from the same zoological institution. One frog was found dead, and the other frog had been ill for several days with a bloated abdomen and lethargy. On necropsy, large, pale multilobulated masses replaced the left ovary in both frogs, and one frog also had numerous smaller nodules scattered throughout the coelomic viscera. Histologically, these masses were composed of sheets and cords of polyhedral discrete germ cells consistent with the diagnosis of dysgerminoma. Neoplastic cells stained positive with immunohistochemistry for Oct4, which has been reported to detect stem cells including germ cells in a variety of species, including humans. Ovarian tumors are uncommonly encountered in both reptiles and amphibians, and this report is the first report of dysgerminoma in any amphibian species.

Renal myxosporidiasis in Asian horned frogs (Megophrys nasuta).

Renal myxosporidiasis and associated lesions were seen in Asian horned frogs, Megaphrys nasuta, at the Detroit Zoological Institute and the Toledo Zoo. The organism was identified as Chloromyxum sp. on the basis of histopathology, cytology, and electron microscopy. Histologic changes in the kidneys included varying degrees of renal tubular dilation and necrosis, and mild to severe nonsuppurative tubulointerstitial nephritis associated with vegetative stages of the myxosporidian. This is the second known identification of Chloromyxum sp. in amphibian kidneys, and the first report of death attributed primarily to the parasite.