Ehrlichiosis was first described in dogs in 1935 and was not recognized as a human disease until the last half of the 20th century. Bacteria of the genus Ehrlichia cause a variety of diseases, both in humans and animals. Scientists continue to discover new species and to recognize different ways they cause disease. The bacteria are spread to humans through tick bites.

Two types of human ehrlichiosis were found in the U.S. in the late 1980s, human monocytic ehrlichiosis (HME) and human granulocytic ehrlichiosis (HGE). HME is now referred to as ehrlichiosis. One of three Ehrlichia species, E. chaffeensis, causes HME. HGE is now known as anaplasmosis. Anaplasma phagocytophilum (previously known as Ehrlichia phagocytophilum), causes HGE.

General Information and Resources

Mailing Address

Disease Surveillance and Epidemiology Section
Mail Code: 3082
P.O. Box 149347
Austin, TX 78714-9347
United States

Physical Address

Disease Surveillance and Epidemiology Section
Moreton Building, Suite M-631
1100 West 49th Street
Austin, TX 78756-3199
United States