Blastomycosis is a disease caused by the dimorphic fungus Blastomyces dermatitidis, which exists as a mold in the environment and as a pathogenic yeast form in the body. The reservoir for B. dermatitidis is moist soil enriched with decomposing organic debris. The fungus is endemic in Ontario, Manitoba, and the south-central, south-eastern, and mid-western United States. Transmission occurs by inhalation of spores after disturbance of contaminated soil.
In 2014, 32 blastomycosis cases were reported, similar to the 34 cases reported in 2013. The median age of 2014 cases was 42 years (range, 13 to 78 years); 22 cases (69%) were male. Twenty-one (66%) cases were white, 2 (6%) were black, 2 (6%) were American Indian, 1 (3%) was of another race, and 6 (19%) were of unknown race. Twenty-four (75%) cases were hospitalized for a median of 7 days (range, 1 to 24 days); 1 (3%) case died as a result of their infection. Twenty-four (75%) cases had pulmonary infections, 1 (3%) case had an extrapulmonary infection, and 7 (22%) cases had disseminated infections.
From 1999 to 2014, 511 blastomycosis cases were reported in Minnesota; the median number of cases annually was 33 (range, 22 to 49). During this time, 103 (27%) of the 380 cases for whom exposure information was available, were likely exposed in St. Louis County, 38 (10%) likely exposed in Itasca County, 21 (6%) cases in Cass County, 14 (4%) cases in Beltrami County, 13 (3%) cases in Chisago County, and 10 (3%) cases in Washington County; these counties are known to be endemic for blastomycosis in Minnesota (Figure 2).
- For up to date information see>> Blastomycosis (Blastomyces dermatitidis)
- Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2014