August 2009, Volume 39 Number 8 , p 59 - 59
CAUSED BY ORGANISMS in the genus Ehrlichia , the term ehrlichiosis describes several bacterial diseases that affect both humans and animals. 1 Ehrlichiae are transmitted by the bite of an infected tick, primarily by the Lone Star tick in the United States. Two ehrlichial species, E. chaffeensis and E. ewingii, cause most of the infection in humans in the United States. People of all ages can be affected, with most cases occurring between May and July. 2
Incidence and transmission
Ehrlichiosis is relatively uncommon, but the number of cases reported by state health departments to the CDC has increased from about 100 per year in 1999 to 600 per year in 2006. The incidence ...