Dr. Stafford Tick Management Handbook - Newtown, CT

Staffordtransmitted by the Brown dog tick since 1935. HME was . rstrecognized in the United States in 1986 in a patient who wasbitten by a lone star tick in Arkansas. The organism, closelyrelated to E. canis, was isolated from another patient at theFort Chaffee Army Base and named E. chaffeensis. Thispathogen is associated with monocytes, another type of whiteblood cell. The DNA of E. chaffeensis has been detected inlone star ticks from Connecticut and Rhode Island, so casesof HME may occur in southern New England. Unlike HGA,white-tailed deer rather than mice are the likely reservoir forE. chaffeensis.Clinically, HME resembles HGA with similar nonspeci.c viral-like symptoms appearing a few days to a coupleThe Connecticut Agricultural Experimentation StationMorulae of E. chaffeensis incytoplasm of monocyte (CDC).of weeks after the tick bite and range from mild to severe. Subclinical cases may be relativelycommon. And like HGA, patients usually will develop leucopenia, thrombocytopenia and elevatedliver enzymes. HME has been confused with other diseases including Rocky Mountain spottedfever (RMSF). Before Ehrlichia was linked with the disease, cases may have been included in whatwas called “Rocky Mountain spotless fever”. A skin rash is uncommon in adults (< 10%), but ismore common in children even though cases in children are less common (