Generalized dermatophytosis caused by Trichophyton equinum in 8 juvenile black bears in California.

From 2014-2019, 8 juvenile black bears (Ursus americanus) from different geographic regions were presented to the California Department of Fish and Wildlife because of emaciation, alopecia, and exfoliative dermatitis that resulted in death or euthanasia. Autopsy and histopathology revealed that all 8 bears had generalized hyperkeratotic dermatitis, folliculitis, and furunculosis. Skin structures were heavily colonized by fungal hyphae and arthrospores; fungal cultures of skin from 7 bears yielded Trichophyton equinum, a zoophilic dermatophyte reported only rarely in non-equid species. Additional skin conditions included mites (5), ticks (2), and coagulase-negative Staphylococcus sp. infections (2). No other causes of morbidity or mortality were identified. Molecular comparisons performed at the University of Texas Fungal Reference Laboratory determined that all isolates produced identical banding patterns, potentially representing a clonal population. Dermatophytosis is commonly localized and limited to the stratum corneum of the epidermis and hair follicles. Generalized disease with dermal involvement is rare in immunocompetent individuals; illness, malnutrition, age, or immunosuppression may increase susceptibility. Underlying causes for the severe disease impact in these bears were not evident after physical or postmortem examination. The mechanism by which bears from different geographic locations had severe, T. equinum-associated dermatophytosis from a potentially clonal dermatophyte could not be explained and warrants further investigation.

Marek's Disease in Backyard Chickens, A Study of Pathologic Findings and Viral Loads in Tumorous and Nontumorous Birds.

Marek's disease (MD) is a major cause of mortality in backyard chickens. The diagnosis of MD is complex, however, and knowledge of Marek's disease virus (MDV) in spontaneous field cases such as in backyard chickens is largely unknown. In this study, 40 backyard chickens with a presumptive MD diagnosis based on histologic lymphoid infiltrations in peripheral nerves with and without lymphomas were investigated. Twenty-eight of the birds were submitted to the diagnostic laboratory for disease explorations, and 12 chickens were from a flock in which some members demonstrated anisocoria and pupil irregularities compatible with ocular MD. Histologic scores were established for brain, peripheral nerves, heart, lung, liver, kidney, and gonad sections, ranging from mild (+) to severe (+++) lymphoid infiltrations. Twelve chickens had gross lymphomas, and all but two chickens had mild to severe peripheral nerve lymphoid infiltrates. There were no age or breed predispositions in the study group. Quantification of serotypes MDV-1, -2, and -3 performed with real-time PCR demonstrated high correlation (R2 = 0.94) between fresh and fixed spleen specimens, as well as between histopathology scores and MDV-1 viral loads. MDV-2 DNA was detected in a portion of the chickens, likely consistent with naturally occurring virus, whereas the vaccine strain MDV-3 was rarely detected. Significant differences in MDV-1 viral loads between tumorous and nontumorous chickens were observed, in which a ratio of MDV-1 glycoprotein B/glyceraldehyde-3-phosphate dehydrogenase ≥ 0.5 was suggestive of gross tumors in this study. We propose that real-time PCR may be a good tool for MD diagnosis in backyard chickens.