Blastomyces dermatitidis, fungal ecology, mycoses, environmental exposure, blastomycosis
Blastomycosis is an endemic fungal infection. In rural northern Wisconsin, blastomycosis cases are associated with certain environmental features including close proximity to waterways. Other studies have associated blastomycosis with particular soil chemicals. However, blastomycosis also occurs in urban and suburban regions. We explored the geodemographic associations of blastomycosis cases in the more urban/suburban landscape of eastern Wisconsin.
We conducted a retrospective study of 193 laboratory-identified blastomycosis cases in a single eastern Wisconsin health system, 2007–2015. Controls were 250 randomly selected cases of community-diagnosed pneumonia from a similar time period. Geographic features of home addresses were explored using Google Maps. Categorical variables were analyzed with chi-square or Fisher’s exact tests and continuous variables by two-sample t-tests. Stepwise regression followed by binary logistic regression was used for multivariable analysis.
Compared to pneumonia cases, blastomycosis cases were younger (47.7 vs. 55.3 years) and more likely to be male (67.9% vs. 45.6%), nonwhite (23.2% vs. 9.7%) and machinists, automobile workers/mechanics or construction workers (32.7% vs. 7.2%); P < 0.001 for all. These relationships remained significant on multivariable modeling. Case home sites, compared to controls, were more likely to have water frontage, (17.6% vs. 7.5%, P = 0.004), be > 0.5 acres (30.4% vs. 14.2%, P = 0.0002), be < 0.25 miles from an automobile repair facility or junkyard (35.9% vs. 19.4%, P = 0.0005), and be < 0.1 miles from a park, forest or farm field (54.9% vs. 39.6%, P = 0.002). Only the latter association remained on multivariable analysis.
Eastern Wisconsin blastomycosis case subjects were younger, more often male and more likely to live near parks/forests/fields. Novel associations of blastomycosis cases with machinery- and automobile-related occupations and/or facilities should be further explored.
Huber ME, Baumgardner DJ, Kram JJ, Lemke MA. Geodemographic features of human blastomycosis in eastern Wisconsin. J Patient Cent Res Rev. 2016;3:90-98. doi: 10.17294/2330-0698.1251