Cases of transfusion-transmitted babesiosis occurring in nonendemic areas: a diagnostic dilemma.

BACKGROUND: Transfusion-transmitted babesiosis (TTB) has been rapidly increasing in incidence since the beginning of the 21st century. Asymptomatic individuals with Babesia infection are able to donate blood in the United States because of the lack of specific blood donation testing. Blood products collected in Babesia-endemic areas are distributed nationally; thus, clinicians in nonendemic states may fail to include babesiosis in the differential diagnosis of a patient who had a recent transfusion history and a fever of unknown origin.

STUDY DESIGN AND METHODS: We report the details of two cases of clinical transfusion-transmitted babesiosis and one asymptomatic infection identified in red blood cell recipients in two nonendemic states (South Carolina and Maryland), which, when combined with three recent additional cases in nonendemic states, totals six recipient infections in three nonendemic states.

RESULTS: Delayed diagnosis of transfusion-transmitted babesiosis places patients at risk for increased morbidity and mortality and may result in clinical mismanagement or unnecessary treatments. A peripheral blood smear should be reviewed in any patient with a recent transfusion and a fever of unknown origin. Prompt communication of the diagnosis among physicians is key to ensuring that patients with transfusion-transmitted babesiosis are treated expeditiously, and a transfusion service investigation is necessary to identify additional recipients from the same donor.

CONCLUSION: TTB is appearing in traditionally nonendemic states because of blood product distribution patterns. Clinicians should include TTB on the differential diagnosis in any patient presenting who had a recent transfusion history and a fever of unknown origin, regardless of where the transfusion took place.