Treatment of Babesiosis in Asplenic Patients

PROTOZOA of the genusBabesiaare tick-borne intraerythrocytic parasites that are transmitted to many species of wild and domesticated animals. Human infection shows two different patterns dependent on immunologic status. In the host with an intact spleen, the infection either is asymptomatic1or causes a moderately severe, febrile, hemolytic illness.2However, these patients invariably recover with only symptomatic care. In contrast, splenectomized persons experience overwhelming intraerythrocytic infections with high fevers, severe toxic reactions, renal failure, and hepatic decompensation.3The outcome in these cases has frequently been fatal.4To date, no chemotherapeutic agent has been found to be active against this parasite in man.5 We recently encountered a critically ill splenectomized patient with babesiosis who responded clinically to quinine sulfate treatment with prompt defervescence and rapid reduction in the level of parasitemia. Report of a Case A 36-year-old man entered the Kaiser Foundation Hospital, Panorama City,