Human ehrlichiosis is caused by at least three distinct kinds of bacteria that are transmitted by tick bites: Ehrlichia chaffeensis, Ehrlichia ewingii, and Anaplasma phagocytophilum
Lone star ticks (Amblyomma americanum), called for the solitary white dot on their backs, are the principal source of ehrlichiosis in humans. Furthermore, lone star ticks are aggressive human biters, and they are the most frequent tick to attack people in the southern and south central United States.
Moreover, dog ticks (Dermacentor variabilis) and deer ticks (Ixodes scapularis) may be infected with and transmit the bacterium that causes human ehrlichiosis.