Reported Cases of Human Anaplasmosis in Minnesota by Year

In 2014, 448 confirmed or probable cases of anaplasmosis (8.3 cases per 100,000 population) were reported, down from the 627 cases reported in 2013. Despite these occasional decreases in reported cases, the overall trend is an increase in yearly case totals over time.  Two hundred ninety-two (65%) cases reported in 2014 were male. The median age of cases was 59 years (range, 3 to 87 years), 20 years older than the median age of Lyme disease cases.  As is typical, most cases had illness onsets during the summer months, with 58% of cases reporting illness onsets in June and July.  In 2014, 124 (28%) anaplasmosis cases were hospitalized at some point for their infection, with a median duration of 4 days (range, 2 to 17 days).

The number of anaplasmosis cases has been increasing since the first cases of HA were reported in Minnesota in the 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.

Updated Friday, August 29, 2014 at 09:15AM