C-198. Fatal Transfusion-Transmitted Babesia microti

D. E. Blue^1,2, J. Cruz³, A. Limiac², S. Spinola¹, T. E. Davis¹, D. Waxman³, L. McCarthy¹, D. Smith^1,2;
¹Indiana Univ. Sch. of Med., Indianapolis, IN, ²Clarian Hlth. Partners (Methodist-IU-Riley Hosp.), Indianapolis, IN, ³Indiana Blood Ctr., Indianapolis, IN.

Background: Fatal transfusion-transmitted B. microti has an estimated incidence of <1:1,000,000 per unit of transfused red cell containing blood products. The disease is usually asymptomatic; however, fatal infections occur in asplenic, elderly or immunosuppressed individuals. Case Report: The 61-year-old female patient had renal disease requiring dialysis. Forty-five days prior to admission she received two units of packed red cells and then two more. One day prior to admission, the patient complained of nausea and fever. Blood cultures were ordered and antibiotics administered. Upon returning to the rehabilitation facility, she spiked temperatures to 103^oF and was admitted to the hospital. She was hypotensive, requiring vasopressor support, and appeared to be septic. The blood smear revealed trophozoites in 5 to 15% of red cells, probable species: Plasmodium falciparum vs. B. microti. Treatment with intravenous quinidine and clindamycin was begun. A red cell exchange reduced parasitemia to 1%. Despite appropriate medication, the patient developed disseminated intravascular coagulation and expired 6 days later. Since she was confined indoors and did not travel, the only risk factor was transfusion. Results: Babesia was confirmed morphologically by CDC with 6% parasitemia and PCR positivity for B. microti from the patient’s specimen at admission. The three donors available for testing were negative for B. microti and all samples were negative for P. falciparum by PCR. One blood donor and the patient were positive for B. microti by immunofluorescent antibody (IFA). The seropositive donor had no recollection of a tick bite and did not travel to endemic areas. Conclusion: The above clinical presentation and course is not atypical for rare fatal cases of transfusion-transmitted Babesia. This is an unusual case as it arose in the Midwest. With the expanding Midwest white-tailed deer populations harboring the vector, Ixodes scapularis, studies to determine the regional incidence of Babesia microti seropositive blood donors may be warranted.

164/C. Diagnostic Mycobacteriology - All Methods and Susceptibility

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