Anaplasmosis is a tick-borne disease caused by the bacterium Anaplasma phagocytophilium. The disease is transmitted to humans by bites from black-legged ticks (Ixodes scapularis) and western black-legged ticks (Ixodes pacificus). Symptoms usually occur within 1-2 weeks of being bitten by an infected tick and include fever, headache, chills, and muscle aches.
Anaplasmosis was first recognized as a human disease in the mid-1990s, but did not become a reportable disease until 1999. The number of cases has increased steadily over the years, from 348 cases reported in 2000 to 1,006 cases in 2008. Anaplasmosis is most frequently reported from the upper Midwest and Northeast. Six states (New York, Connecticut, Massachusetts, Rhode Island, Minnesota, and Wisconsin) account for 88% of all reported cases. Though West Virginia has had no confirmed cases of anaplasmosis, black-legged ticks are found in specific regions of the state. The Eastern Panhandle, for example, has an established Ixodes scapularis population. This area also accounts for the majority of Lyme disease cases in the West Virginia.