Dermacentor variabilis

Dermacentor variabilis

The American dog tick Dermacentor variabilis, is a species of tick that is known to carry bacteria responsible for several diseases in humans, including Rocky Mountain spotted fever and tularemia (Francisella tularensis).

Though D. variabilis may be exposed to Borrelia burgdorferi, the causative agent of Lyme disease, these ticks are not competent vectors for the transmission of this disease. Dermacentor variabilis may also carry Anaplasma phagocytophilum, the causative agent of HGE (human granulocytic ehrlichiosis), and Ehrlichia chaffeensis, the causative agent of HME (human monocytic ehrlichiosis).