Transfusion-acquired babesiosis in a nonendemic area.

Babesiosis is a tick-borne illness endemic to the coastal areas of southern New England. Despite the enormous safety measures that transfusion and blood bank services perform for each product, transfusion of blood products is not without risk. The majority of transfusion-related reactions and complications are recognized soon after transfusion. We report a case of transfusion-acquired babesiosis in Washington State that presented 4 weeks after transfusion of a blood product from a donor living in a babesiosis-endemic area.