Blastomycosis is 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 2015, there were 34 reported blastomycosis cases. This is similar to the 32 cases reported in 2014, and 34 in 2013. The median age of the cases was 45 years (range, 5 to 75 years); 27 cases (79%) were male. Twentyseven cases were white, 1 (3%) was black, 2 (6%) were American Indian, 3 (9%) were Asian/Pacific Islander, and 1 was of unknown race. Twenty-four (71%) cases were hospitalized for a median of 6.5 days (range, 2 to 53 days). In 1 case, blastomycosis was a contributing factor to death. Twentyfive (73%) cases had pulmonary infections, 4 (12%) cases had extrapulmonary infections, and 5 (15%) had disseminated infections.
From 1999 to 2015, 544 blastomycosis cases were reported; the median number of cases annually is 33 (range, 22 to 49). Exposure information is available for 429 cases. The largest number of cases, 111 (26%), were likely exposed in St. Louis County, 42 (10%) cases were likely exposed in Itasca County, 26 (6%) in Cass County, 14 (3%) in Beltrami County, and 14 (3%) in Chisago County. (see Figure 2 for endemic counties).
- For up to date information see>> Blastomycosis (Blastomyces dermatitidis)
- Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2015