Babesiosis Transmitted by a Transfusion of Frozen-Thawed Blood.

: Babesiosis in the United States is caused by Babesia microti, a hemosporozoan parasite of wild rodents that is transmitted to humans by the tick, Ixodes dammini (1). Almost 100 clinical and subclinical cases of babesiosis have been reported from the coastal areas and off-shore islands of Long Island, New York and Massachusetts (2). We report the first case of infection due to Babesia microti in a splenectomized woman after transfusion with frozen-thawed erythrocytes (deglycerolized, washed) from a seropositive donor. This patient is the youngest asplenic person and the only person with thalassemia major to have had a documented, (C) 1982 American College of Physicians