Infection with a Babesia-Like Organism in Northern California

Abstract

Human babesiosis is a tick-transmitted zoonosis associated with two protozoa of the family Piroplasmorida: Babesia microti (in the United States) and B. divergens (in Europe). Recently, infection with an unusual babesia-like piroplasm (designated WA1) was described in a patient from Washington State. We studied four patients in California who were identified as being infected with a similar protozoal parasite. All four patients had undergone splenectomy, two because of trauma and two for other medical reasons. Two of the patients had complicated courses, and one died. © 1995, Massachusetts Medical Society. All rights reserved.