Anaplasmataceae

The order Rickettsiales includes several obligate intracellular gram-negative pathogenic bacteria. The family Anaplasmataceae includes intraphagosomal pathogens of the genera Anaplasma , Ehrlichia , and Neorickettsia . Ehrlichia canis is the major pathogen responsible for causing the disease canine monocytic ehrlichiosis. It is transmitted by the Rhipicephalus sanguineus tick, commonly referred to as the brown dog tick. Ehrlichia ruminantium is an important tick-borne pathogen in sub-Saharan Africa, as it is responsible for causing heartwater disease in domestic and wild ruminants. Ehrlichia chaffeensis was first identified as the pathogen causing the human monocytic ehrlichiosis. In the late 1970s, Potomac horse fever in the Potomac River Valley of Maryland, United States, was recognized as an epidemic in horses. The pathogen Neorickettsia risticii is the causative agent of this disease. The reservoir of infection for Neorickettsia helminthoeca is the fluke Nanophyetus salmincola .