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.

Immunocontraception has become an increasingly valuable tool in the population management of captive exotic ungulates. Although porcine zona pellucida vaccine (PZP) was used successfully in other cervids, a previous study with fallow deer (Cervus dama) suggested that the vaccine did not work in this species. In the current study, PZP was tested in two captive herds of fallow deer. Antibody titers were monitored over a 3-year period to evaluate three different adjuvant protocols, and the vaccine was applied to an entire herd to determine the impact on fawning rates. In a semi-free-ranging herd, antibody titers rose from preimmunization levels of 2.6% of positive control serum to 56.5% 4 weeks after initial inoculations, to 65.1% at 1 year, and to 81.3% at 2 years, after a single annual booster was applied. Fawn production in this herd was reduced significantly over 3 years. The adjuvant protocol of Freund's Modified Adjuvant s (FMA) for the initial inoculation followed by a booster with Freund's Incomplete Adjuvant s (FIA), and the protocol of FMA for the initial inoculation followed in 3 weeks by a booster with FMA both produced significantly higher antibody titers than the 3 Â FIA (3 weeks apart) protocol after year 1. The FMA+FMA protocol produced significantly higher titers than the 3 Â FIA protocol at year 2, but was not different from the titers produced by the FMA+FIA protocol at year 2.

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 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.

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.