Babesiosis

A week after the onset of headache, fever, chills, nausea, weakness, and malaise, a 23-year-old man presented to the emergency department of a hospital on Long Island in New York. He reported that analgesics had not eased his symptoms. The patient's only past hospitalization was a splenectomy secondary to an auto accident at age 16.

Clinical findings included pale conjunctivae, jaundice, and tachycardia. There was no rash.

Laboratory test results revealed anemia and thrombocytopenia, and both lactate dehydrogenase levels and reticulocyte cell count were elevated. A peripheral blood smear showed the parasite of tick-borne babesiosis, pictured here(arrow). The patient had no recollection of being bitten by a tick.

In the United States, this tick-borne disease caused by the parasite Babesia microti is found most commonly in coastal areas of Long Island, New Jersey, Massachusetts, and Maryland. Babesiosis is spread by the deer tick, Ixodes dammini, the same vector that transmits Lyme disease. The patient usually presents with a high fever, chills, diaphoresis, and malaise. Intravascular hemolysis can occur and may cause severe morbidity if the disease is not diagnosed and treated early.

This patient was treated with intravenous clindamycin and blood transfusions for intravascular hemolysis. After 2 weeks of therapy, his parasite level dropped and he was afebrile. The patient was discharged from the hospital in stable condition.