A typical babesiosis in an immunocompetent patient.

Babesiosis is a tick-borne infectious disease, caused by an intraerythrocytic parasite of the genus Babesia. It has clinical, biological and microbiological similarities with Plasmodium related infections. In rare cases, babesiosis may be complicated by hemophagocytic lymphohistiocytosis, which occurs preferentially in the immunodeficient patient. We report here the case of a non-immunocompromised patient living in Manhattan, New York hospitalized for a complicated babesiosis of a hemophagocytic lymphohistiocytosis. After 7 days of hospitalization and treatment by azithromycin 500 mg/day and atovaquone 750 mg twice a day, the patient was discharged with an improvement in clinical symptoms and biological parameters.