German shepherds often develop fatal hemorrhage in the late chronic phase of the illness, whereas mixed breeds and beagles generally do not. The primary target cell for HGE is the granulocyte, and for HME the primary target cell is the macrophage. State health departments reported 742 cases of HME and 449 cases of HGE during 1986-1997. HME was reported most commonly from the southeastern and south-central states, while HGE was reported most often from Wisconsin and Minnesota. A median age of 44 years is reported.
Onset is abrupt or subacute.
Symptoms are nonspecific and resemble those of Rocky Mountain spotted fever. All patients have fever greater than 38 C. Headache Myalgia and arthralgia Anorexia and nausea Malaise and photophobia Skin rash Rash is less common in ehrlichiosis than in Rocky Mountain spotted fever. It is more common in children than adults. The patient may be confused. Ehrlichia species, members of the family Rickettsiae, are gram-negative, obligate, intracellular coccobacilli that resemble Rickettsia species.