[Human granulocytic ehrlichiosis, a tick-borne disease].

A 69-year-old male presented at a first-aid department in Connecticut (USA) with severe headache, fever and myalgia of three days' duration. Just before he became ill, an engorged tick had been noted on his back and removed. Laboratory results included a decreased white cell count and platelet count and elevated transaminases. So-called morulae consisting of microorganisms were detected in a peripheral blood smear of the day of admission. Treatment for human granulocyte ehrlichiosis with doxycycline for two weeks resulted in prompt and full recovery and after four weeks repeat laboratory tests were all within normal limits. Human granulocyte ehrlichiosis should be considered in a patient with a recent tick bite who develops fever, headache and myalgias, in the presence of leukopenia or thrombocytopenia, even in Western Europe.