Babesiosis is a malaria-like illness caused by the protozoan, Babesia microti or other Babesia organisms, that infects red blood cells. B. microti is transmitted to humans by bites from I. scapularis (the blacklegged tick or deer tick), the same vector that transmits the agents of Lyme disease, human anaplasmosis, one form of human ehrlichiosis, and a strain of Powassan virus. Babesia parasites can also be transmitted by blood transfusion. Babesia infections can range in severity, and while most people have asymptomatic infections, people with weak immune systems, underlying health conditions, and the elderly may become seriously ill.
In 2014, 49 confirmed and probable babesiosis cases (0.9 per 100,000 population) were reported (Figure 1), down from the 69 reported cases in 2013. Despite this decrease, yearly case totals since 2005 (range, 10 to 72) have been consistently higher than reported totals from 1996 to 2004 (range, 0 to 9). In 2014, 34 (69%) cases occurred in males. The median case age was 68 years (range, 12 to 91 years), up from 66 in 2013, and older than the median ages for both anaplasmosis (59 years) and Lyme disease (39 years). Onsets of illness peaked in the summer months; 29 (60%) of 48 patients with known onset reported first experiencing symptoms in June, July, or August. Twenty-seven (55%) cases were hospitalized for their infection in 2014 for a median duration of 5 days (range, 3 to 15 days). Although severe complications like organ failure were reported in 7 cases, there were no deaths attributable to babesiosis in 2014.
- For up to date information see>> Babesiosis (Babesia microti)
- Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2014