Blastomyces dermatitidis Raw sequence reads. Blastomyces dermatitidis

Outbreaks of blastomycosis, caused by the fungus Blastomyces dermatitidis, occur in endemic areas of the United States and Canada but the geographic range of blastomycosis is expanding. Previous studies inferred the location of B. dermatitidis through epidemiologic data associated with outbreaks because culture of B. dermatitidis from the environment is often unsuccessful. In this study, we used a culture-independent, PCR-based method to identify B. dermatitidis DNA in environmental samples. We tested 250 environmental samples collected in Minnesota, either associated with blastomycosis outbreaks and random or environmental samples collected from high- and low-endemic regions to determine basal prevalence of B. dermatitidis in the environment. Ecological niche analysis identified latitude, longitude, elevation, and site classification as environmental parameters associated with the presence of B. dermatitidis. Using this analysis, a Random Forest model predicted B. dermatitidis presence in basalrandom environmental samples with 75% accuracy. These data support use of culture-independent, PCR-based environmental sampling to predict blastomycosis risk and track spread of B. dermatiditis into new regions and to characterize the unknown B. dermatitidis environmental niche.