Blastomycosis is caused by the dimorphic fungus Blastomyces dermatitidis, which exists as a mold in the environment and a pathogenic yeast form in the body. The reservoir is moist soil enriched with decomposing organic debris. Transmission occurs primarily by inhalation of spores after disturbance of contaminated soil.
In 2016, there were 39 reported blastomycosis cases, a small increase over the 34 cases in 2015, and 32 in 2014. The median age of 2016 cases was 48 years (range, 12 to 80 years); 28 (72%) were male. Thirty-five (90%) cases were white, 2 (5%) were Asian/Pacific Islander, 1 (3%) was American Indian, and 1 was of unknown race. Twentythree (59%) cases were hospitalized for a median of 7 days (range, 1 to 55 days). Three cases died, and in 2 of these blastomycosis was the cause of death. Thirteen cases (33%) had immunocompromising health conditions or medications, including 8 (21%) with diabetes, and 2 (5%) that were posttransplant patients. Thirty-three (85%) cases had pulmonary infection, 1 (3%) had extra-pulmonary infection, and 5 (13%) had disseminated infection.
From 1999 to 2016, 584 blastomycosis cases were reported; the median annual number was 33 (range, 22 to 48). Exposure information is available for 479 cases. The largest number, 123 (25%), were likely exposed in St. Louis County. Fifty-five (11%) cases were likely exposed in Itasca County, 29 (6%) in Cass County, 16 (3%) in Beltrami County, 15 (3%) in Chisago County, and 14 (3%) in Hennepin County. (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, 2016