A cluster of transfusion-associated babesiosis cases traced to a single asymptomatic donor

Context The risk of acquiring babesiosis by blood transfusion is largely un known since in areas where it is endemic it is often an asymptomatic infect ion. Objective To investigate and treat a duster of blood transfusion-associated babesiosis cases, Design Case series and epidemiologic investigation. Setting Urban inner-city hospital. Patients Six persons who received Babesia microti-infected blood components from a donor, Main Outcome Measure Diagnosis and successful therapy of babesiosis followi ng transfusion. Results Six individuals (1 adult, 1 child, and 4 neonates) were exposed to products from a single blood donation by an asymptomatic Babesia-infected d onor. Three of the 6 exposed patients became parasitemic, Polymerase chain reaction testing, animal inoculation studies, and indirect immunofluorescen t antibody testing were used to confirm the presence of Babesia microti in the donor's blood and to establish the presence of infection in 3 of the 6 recipients, The 3 infected recipients and 1 additional recipient were treat ed without incident. Conclusion Physicians should consider babesiosis in the differential diagno sis of a febrile hemolytic disorder after blood transfusion. Prompt diagnos is is important since babesiosis is responsive to antibiotic therapy and, u ntreated, can be a fatal disease in certain risk groups.