Blastomycosis, 2018

In 2018, 58 blastomycosis cases were reported, the highest number since enhanced surveillance began in 1999. The 2 previous years (2017, 2016) had the third and fourth highest counts, 44 and 39 cases. The median age was 45.5 years (range, 5 to 90); 45 (78%) were male. Thirty-eight (75%) cases were white, 8 (16%) were black, 2 (4%) were American Indian/Alaska Native, 2 (4%) were Asian/Pacific Islander, 1 (2%) was mixed race, and 7 were unknown race. Thirty-five (60%) cases were hospitalized for a median of 7 days (range, 1 to 197). Eight (14%) cases died, which is a higher fatality rate than the normally observed 9-10%, and the second year in a row with an increased case fatality rate. Blastomycosis was the cause of death for all 8. Twenty-one cases (40%) had immunocompromising health conditions or medications, including 12 (28%) with diabetes, 3 (9%) taking corticosteroids, and 2 (5%) on medications for rheumatoid arthritis. Forty-two (72%) cases had pulmonary infection, 3 (5%) had extrapulmonary infection, and 13 (22%) had disseminated infection.

From 1999 to 2018, 671 blastomycosis cases were reported; the annual median is 33.5 cases (range, 22 to 58). The median annual incidence statewide is 0.63 cases/100,000 population, but was 1.03 cases/100,000 in 2018. Exposure information is available for 559 cases. The largest number, 131 (23%), were likely exposed in St. Louis County. Seventy (13%) cases were likely exposed in Itasca County, 43 (8%) in Cass County, 19 (3%) in Hennepin County, 17 (3%) in Chisago County, and 16 (3%) in Beltrami 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, 2018