Histopathology of Ophidiomyces in Prairie rattlesnakes.

Histologic lesions in prairie rattlesnakes (Crotalus viridis) experimentally challenged with Ophidiomyces ophidiicola. [A/B], Skin and subcutis from 26°C inoculated snake. A) The epidermis is moderately to markedly hyperplastic with abundant serocellular crusts and the subcutis has several large granulomas (hematoxylin and eosin (HE, 20x); B) Gomori’s methenamine silver (GMS) staining highlights fungal hyphae in the crusts, epidermis, and granulomas. [C-H], Subcutis and skeletal muscle from 20°C inoculated snake. C) There is extensive necrosis and hemorrhage in the subcutis and skeletal muscle with mild inflammation (HE, 20x); D) GMS staining highlights fungal hyphae within necrotic tissues. E/F, Skin, ulcer from 20°C inoculated snake. E) The epidermis is absent (ulceration) and the exposed dermis is smudged and hypereosinophilic (degeneration). The surface is overlain by thick mat of fungi including superficial arthroconidia and fungal hyphae in dermis and deeper tissues (HE, 20x). F) GMS staining shows unfettered fungal invasion. G) Superficial fungal mats have cylindrical arthroconidia (*) at the air surface (HE, 60x); H) Superficial fungal mats with GMS staining (HE, 60x).