Patients can present with fever, headache, myalgias, and malaise. Laboratory tests may reveal thrombocytopenia, leukopenia, and evidence of liver damage.
Humans contract the disease after a bite by an infected tick of the species Amblyomma americanum.
Those with an underlying immunodeficiency (such as HIV) appear to be at greater risk of contracting the disease. Compared to HME, ewingii ehrlichiosis has a decreased incidence of complications.
In endemic areas, a high index of suspicion is warranted, especially with a known exposure to ticks. The diagnosis can be confirmed by using PCR. A peripheral blood smear can also be examined for intracytoplasmic inclusions called morulae.
^Xiong Q, Bao W, Ge Y, Rikihisa Y (April 2008). "Ehrlichia ewingii infection delays spontaneous neutrophil apoptosis through stabilization of mitochondria". The Journal of Infectious Diseases. 197 (8): 1110–8. doi:10.1086/533457. PMID18462160.