From 1996 to 2012, 310 cases of babesiosis were reported in Minnesota. In 2012, 41 confirmed and probable babesiosis cases (0.75 per 100,000 population) were reported, a 43% decrease from the 2011 record of 72 cases. The median number of 29 cases (range, 9 to 72) reported from 2004 through 2012 is considerably higher than the median number of 2 cases (range, 0 to 7) from 1996 to 2003.
The number of babesiosis cases has been increasing since it first became reportable in mid-1990s. A variety of factors, including increasing physician awareness, increasing infection rates in ticks, and expanding tick distribution may have led to this trend.
Cases of babesiosis in 2012 ranged in age from 1 to 82 years; the median age (57 years) was greater than that of Lyme disease (39 years). In 2012, 59% of babesiosis cases were male. Onsets of illness peaked in the summer months, with 22 (55%) of 40 cases with known onset occurring from June through August. At least 1 reported case died from complications of babesiosis in 2012.
- Reported Cases of Babesiosis in Minnesota by Year
Graph showing the number of reported babesiosis in Minnesota by year.
- Reported Cases of Babesiosis in Minnesota by Month of Onset
Bar graph showing reported percent of cases by month of onset.
Most HA cases report likely exposure to blacklegged ticks in the same east-central and north-central Minnesota counties where the risk of Lyme disease is greatest.
- High Risk Areas for Tick-borne Diseases in Minnesota
A map that shows counties of highest Tick-borne risk in Minnesota.