HME occurs across the south-central, southeastern, and mid-Atlantic states. In 2001-2002, the incidence was highest in Missouri, Tennessee, and Oklahoma. The primary vector is the lone star tick (Amblyomma americanum). HME has been found in California in Pacific blacklegged ticks (Ixodes pacificus) and American dog ticks (Dermacentor variabilis).
For further information we refer you to:
CDC's web pages on Ehrlichiosis
