Screening Reduces Risk of Transfusion-Transmitted Babesiosis

HealthDay News — Screening for Babesia microti antibodies and DNA in blood-donation samples is associated with a reduction in the risk of transfusion-transmitted babesiosis, according to a study published in the New England Journal of Medicine.

Erin D. Moritz, PhD, from the American Red Cross in Gaithersburg, Maryland, and colleagues performed arrayed fluorescence immunoassays (AFIAs) for B microti antibodies and real-time polymerase-chain-reaction (PCR) assays for B microti DNA on blood-donation samples from Connecticut, Massachusetts, Minnesota, and Wisconsin. Data on cases of transfusion-transmitted babesiosis were used to compare the proportions of screened vs unscreened donations that were infectious.

The researchers found that 0.38% (335 samples) of the 89,153 blood-donation samples tested were confirmed to be positive. Of these, 20% were PCR-positive; 9 samples were antibody-negative, representing 13% of all PCR-positive samples. There were no reported cases of transfusion-transmitted babesiosis in association with screened donations in Connecticut and Massachusetts while there were 14 cases per 253,031 unscreened donations (odds ratio, 8.6; P =.05). Twenty-nine cases of transfusion-transmitted babesiosis were associated with infected donor blood.

“Blood-donation screening for antibodies to and DNA from B microti was associated with a decrease in the risk of transfusion-transmitted babesiosis,” the authors write.

The study was funded by the American Red Cross and Imugen.

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Moritz ED, Winton CS, Tonnetti L, et al. Screening for Babesia microti in the U.S. blood supply. N Engl J Med. 2016;375:2236-2245. doi: 10.1056/NEJMoa1600897