August 2016


Signalment (JPC #4008764):  A Panamanian golden frog


HISTOPATHOLOGIC DESCRIPTION:  Skin:  Multifocally, there is moderate epithelial hyperplasia, characterized by keratinocytes that are piling up to six layers thick with increased mitotic figures, acanthosis, and mild, multifocal orthokeratotic hyperkeratosis. Within the stratum corneum, including the hyperkeratotic debris, there are numerous round, 5-15 um diameter chytrid thalli, which have 1-2 um thick walls. All three forms of thalli are present and include the following:  multifocal zoosporangium contain multiple discrete basophilic 2-3 um zoospores and have an injection papillae that is oriented away from the epidermis; fewer multinucleate forms with finely granular basophilic cytoplasm, multiple nuclei, and internal septation; and rare uninucleate forms with homogenous basophilic cytoplasm and a single nucleus. Within the hyperkeratotic debris and stratum corneum there are numerous empty thalli outlined by a 2 um thick eosinophilic walls. The hyperkaratotic debris also contains some necrotic debris admixed with numerous 1x3 um coccobacilli. Multifocally within the dermis there are low numbers of lymphocytes and plasma cells.

MORPHOLOGIC DIAGNOSIS:  Skin:  Epidermal hyperplasia, multifocal, moderate, with hyperkeratosis, minimal subacute dermatitis, and numerous intracorneal thalli, etiology consistent with Batrachochytrium dendrobatidis, ornate horned frog (Ceratophrys ornata), amphibian.

ETIOLOGIC DIAGNOSIS:  Chytridiomycotic dermatitis

CAUSE:  Batrachochytrium dendrobatidis

CONDITION:  Chytridiomycosis











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