HUMAN INFECTION with Ehrlichia canis or another closely related rickettsia was described in the United States for the first time in 1986.1 In April of that year, a 51-year-old man developed fever, malaise, myalgia, and headache approximately 12 days after being bitten by ticks while he was planting trees in rural Arkansas. He was hospitalized 5 days after becoming ill.
Upon admission to the hospital, the patient had an oral temperature of 39.7°C (103.5°F), leukopenia, thrombocytopenia, renal failure, and elevated liver enzymes, but no rash. A presumptive diagnosis of "spotless" Rocky Mountain spotted fever (RMSF) was made, and the patient was treated with chloramphenicol and, later, with doxycycline. Cytoplasmic inclusions were observed in peripheral lymphocytes, neutrophils, and monocytes on the seventh day of illness. His illness was complicated by disseminated candidiasis, but he was discharged after 12 weeks of hospitalization without residual problems. Serum samples obtained during the late
From the MMWRMorbidity and Mortality Report Centers for Disease Control, Atlanta. Arch Dermatol. 1988;124(7):993-994. doi:10.1001/archderm.1988.01670070007001