Invasive pulmonary pseudallesheriosis in a cross-breed calf.

Pulmonary pseudallescheriosis was diagnosed in a two-months old calf. Pneumonic lungs with yellow-white nodules on the surfaces revealed granulomatous lesions microscopically. Septate, pleomorphic hyphae were present in the central caseated core with a bright eosinophilic periphery surrounded by polymorphonuclear cells and macrophages followed by a zone of epithelioid cells admixed with lymphocytes and plasma cells. The fungal agent was demonstrated by Grocott's silver methenamine staining. On isolation, morphologically it was found to be indistinguishable from that of Pseudallescheria boydii. It appears to be first report of fatal mycotic pneumonia in a calf due to P. boydii. The emphasis is given for further detailed investigation on this aspect in veterinary mycopathology.