Disseminated Blastomyces dermatitidis, genetic group 2, infection in an alpaca (Vicugna pacos)

Abstract

A 7-year-old, female Huacaya alpaca presented with a 3-week history of left-sided head tilt and mild ataxia. Despite aggressive supportive therapy with empirical antibiotic, anti-inflammatory, thiamine, and anthelminthic therapy, neurologic signs progressed to a right-sided head tilt, positional nystagmus, and episodes of severe ataxia and obtundation. On necropsy, discrete expansile to poorly delineated infiltrative masses with tan, creamy to grumous exudate were observed in the right petrous temporal bone, right middle and inner ear, right cerebellum and medulla as well as in lung, kidney, liver, spleen, lymph nodes, and the gastrointestinal tract. Impression cytology and histology revealed a myriad of intralesional yeast, 10–25 μm in diameter, with double-contoured walls, granular protoplasm, and broad-based budding. Culture characteristics, including conidial morphology and temperature-dependent yeast phase transformation, were consistent with Blastomyces sp. Positive Blastomyces antigenuria was identified on a postmortem sample of urine. Microsatellite typing and sequencing of the internal transcribed spacer region 2 identified the infecting strain as a genetic group 2 isolate of Blastomyces dermatitidis. The present report of camelid blastomycosis adds intracranial blastomycosis to the differential list for camelid neurologic disease in endemic regions.