Transfusion-induced malaria from an asymptomatic carrier.

An asymptomatic malaria carrier who satisfied the currently recommended standards and criteria of the American Association of Blood Banks for blood donation was the source of the transfusion-induced malaria in this study. The risk of transfusion-induced malaria remains a very real threat in the United States. Any case of unexplained fever following transfusion should be considered as possibly caused by malaria. Delay of the proper diagnosis may be due to unfamiliarity of medical personnel with diagnostic criteria for malaria. Persons who give a history of having resided for long periods in malarious regions, even though they have remained asymptomatic for many years while residing in a malaria free area may still carry the more persistent malarial species and, therefore, should be rejected as donors of whole blood.