DisseminatedBlastomyces 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.

What is your diagnosis? Submandibular mass in an alpaca

“…In this case, a deep C2 ulcer was revealed on postmortem examination, which may have contributed to the patient's morbidity. While a similar clinical case of disseminated blastomycosis in an alpaca was recently reported, to our knowledge, this is the first report of microforms found in this or any veterinary species …”

Blastomyces dermatitidispneumonia in a llama

“…1,16 Of the differentials at autopsy (each of which have been recognized in other species at this locale), the paucity of reports regarding the occurrence of cryptococcosis, histoplasmosis, aspergillosis, rhodococcosis, and blastomycosis in camelids, specifically llamas, made these diseases less likely than tuberculosis. 4,[10][11][12]15,23 B. dermatitidis was identified microscopically and confirmed via DNA sequencing, and there was no evidence of mycobacterial infection.…”

“…A 2014 report of disseminated blastomycosis in an alpaca raised the issue of genetic subgroups within the Blastomyces genus and called for active surveillance to expand the knowledge of the genetic and geographic diversity of this pathogen. 12 In addition, differentiation from Blastomyces gilchristii , which was identified in 2013 in a limited geographic range (Wisconsin, Minnesota, and Ontario) but associated with acute respiratory syndrome, was considered critical. 5,7 In order to more completely define the organism in this case, we pursued DNA sequencing.…”

Development and validation of a novel single nucleotide polymorphism (SNP) panel for genetic analysis of Blastomyces spp. and association analysis

“…In that study, 46 nucleotide polymorphisms were identified within 7 gene regions, with 12 SNPs being determined as diagnostic between B. gilchristii and B. dermatitidis . Genotyping of a small number of isolates by both methods indicates that B. gilchristii , the newly proposed species, may be equivalent to microsatellite genetic Group 1 with B. dermatitidis being equivalent to microsatellite genetic Gr 2 [ 7 , 8 ]. This suggests that clinical disease variation is potentially associated with species-specific genetic diversity.…”