Blood Donor Screening for Trypanosoma cruzi |
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Chaga's disease is caused by the parasite, Trypanosoma cruzi. As many as 11 million persons in Mexico and in Central and South America carry the parasite and serve as a potential source of transfusion transmitted disease. The risk of T. cruzi transmission in the United States is increasing because of immigration of infected individuals from endemic countries. Estimates of the incidence of seropositive donors in the United States have ranged from 1 in 5400 to 1 in 25,000 donors.
Transfusion of red blood cells and platelets from infected donors carries the highest risk of transmission, approximately 38%. The risk of transmission from plasma components is considerably lower because T. cruzi is killed by freezing. The lifetime risk of severe heart or intestinal problems in infected individuals averages about 30% and usually occurs many years after the initial infection.
Because of this increasing risk of transfusion transmitted disease, blood centers in the United States began testing donors for antibodies to T. cruzi in June 2007. FDA requires hospitals to participate in a Look-back program which involves identification of all recipients of previously transfused blood components from confirmed positive donors. Physicians will be notified by their hospital transfusion service if one of their patients has been transfused with a blood component from an implicated donor.
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