A fatal case of transfusion-transmitted babesiosis in the State of Delaware.

BACKGROUND: Most cases of human babesiosis in North America are caused by Babesia microti, which is endemic in the northeastern and upper midwestern United States. Although the disease is usually transmitted by a tick bite, there has been an increase in the number of transfusion-transmitted cases reported. We describe a fatal case of transfusion-transmitted babesiosis in a nonendemic state, Delaware.

CASE REPORT: The patient was a 43-year-old Caucasian woman with history of transfusion-dependent Diamond-Blackfan syndrome, hepatitis C, and splenectomy. She was admitted initially for presumptive pneumonia. The next day, a routine examination of the peripheral blood smears revealed numerous intraerythrocytic ring forms, consistent with Babesia. The parasitemia was approximately 5% to 6%. The diagnosis was confirmed by positive polymerase chain reaction (PCR) for B. microti DNA and high titer of antibody to B. microti (1:2048). Despite aggressive therapy including clindamycin and quinine antibiotics, the patient expired 3 days after admission. Subsequently, 13 blood donors were tested for B. microti. All tested donors were negative by PCR. However, one donor living in New Jersey had a significant elevated B. microti antibody titer (1:1024).

CONCLUSIONS: We believe that this is the first reported case of transfusion-transmitted babesiosis in Delaware, a nonendemic state. Our case illustrates that clinicians should consider babesiosis in the differential diagnosis of immunocompromised patients who have fever and recent transfusion history, even in areas where babesiosis is not endemic. It also demonstrates the need for better preventive strategies including more sensitive, specific, and rapid blood donor screening tests to prevent transfusion-transmitted babesiosis.