Babesiosis, 2011

Babesiosis is a malaria-like illness caused by the protozoan Babesia microti or other Babesia organisms. 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.

In 2011, a record number of 72 confirmed and probable babesiosis cases (1.4 per 100,000 population) were reported, a 29% increase over the previous record of 56 cases in 2010. The median number of 27 cases (range, 9 to 73) reported from 2004 through 2011 is considerably higher than the median number of 2 cases (range, 0 to 7) from 1996 to 2003. Fifty-two (72%) babesiosis cases reported in 2011 were male. The median age of cases was 59 years (range, 3 to 90 years). Onsets of illness peaked in the summer months, with 49 (69%) of 71 cases with known onset occurring from June through August. In 2011, 27 (38%) cases were hospitalized for their infection, for a median duration of 4 days (range, 2 to 17 days). At least 1 reported case died from complications of babesiosis in 2011.

• For up to date information see>> Babesiosis (Babesia microti)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2011