Analysis and modeling of environmental prevalence in Minnesota using soil collected to compare basal and outbreak levels.

Outbreaks of blastomycosis, caused by the fungus , occur in endemic areas of the United States and Canada but the geographic range of blastomycosis is expanding. Previous studies inferred the location of through epidemiologic data associated with outbreaks because culture of from the environment is often unsuccessful. In this study, we used a culture-independent, PCR-based method to identify DNA in environmental samples using the BAD1 promoter region. We tested 250 environmental samples collected in Minnesota, either associated with blastomycosis outbreaks or environmental samples collected from high- and low-endemic regions to determine basal prevalence of in the environment. We identified a fifth BAD1 promoter haplotype of prevalent in Minnesota. Ecological niche analysis identified latitude, longitude, elevation, and site classification as environmental parameters associated with the presence of Using this analysis, a Random Forest model predicted presence in basal environmental samples with 75% accuracy. These data support use of culture-independent, PCR-based environmental sampling to track spread into new regions and to characterize the unknown environmental niche. Upon inhalation of spores from the fungus from the environment, humans and animals can develop the disease blastomycosis. Based on disease epidemiology, is known to be endemic in the United States and Canada around the Great Lakes and in the Ohio and Mississippi River Valleys but is starting to emerge in other areas. is extremely difficult to culture from the environment so little is known about the environmental reservoirs for this pathogen. We used a culture-independent PCR-based assay to identify the presence of DNA in soil samples from Minnesota. By combining molecular data with ecological niche modeling, we were able to predict the presence of in environmental samples with 75% accuracy and to define characteristics of the environmental niche. Importantly, we showed the effectiveness of using a PCR-based assay to identify in environmental samples.