infectious diseases
Babesiosis
Introduction
Babesiosis is infection withBabesiaspecies of protozoa. Infections can be asymptomatic or cause a malaria-like illness with fever and hemolytic anemia. Disease is most severe in asplenic patients, older patients, and patients with AIDS. Diagnosis is by identification ofBabesiain a peripheral blood smear, serologic test, or polymerase chain reaction (PCR). Treatment, when needed, is withazithromycinplusatovaquoneor withquinineplusclindamycin. In 2019, there were 2,418 reported cases of babesiosis in the US from the 25 states where babesiosis was a reportable condition (seeCenters for Disease Control and Prevention: Babesiosis Data & Statistics). Endemic areas include the islands and the mainland bordering Nantucket Sound in Massachusetts, Rhode Island, eastern Long Island and Shelter Island in New York, coastal Connecticut, and New Jersey, as well as foci in Wisconsin and Minnesota in the upper Midwest.Babesia duncanihas been isolated from patients in Washington and California. AB. duncani-like strain designated MO-1 has been reported in patients in Missouri. OtherBabesiaspecies transmitted by different ticks infect humans in other areas of the world. In Europe,B. divergensis the principal cause of babesiosis, typically in patients who have had a splenectomy. 