Human babesiosis. Clinical and therapeutic considerations.

During a two-month period, six patients from eastern Long Island were identified as having Babesia microti infection. Diagnosis was based on characteristic blood smears, hamster inoculation, or both. Symptom duration ranged from 19 to 24 days in five patients. The sixth patient, who had previously undergone splenectomy, had a more severe and prolonged illness. No specific therapy was administered to five patients. The patient who had had a splenectomy was treated with chloroquine, quinine, pentamidine, and exchange transfusions. There were no deaths. It appears that most cases of human B microti infection can be effectively managed with symptomatic and supportive care.