Risk factors for Trypanosoma cruzi infection in California blood donors


Department of Pathology, Stanford University; and Associate Medical Director, Stanford Medical School Blood Center, 800 Welch Road, Palo Alto, CA 94304


Background:Trypanosoma cruzi, the protozoan parasite that causes Chagas'disease, is endemic in Central and South America and in Mexico. Risk of infection is related to exposure to insects harboring T. cruzi or to the transfusion of blood from an infected donor. Large numbers of immigrants from endemic areas reside in California, but the frequency with which persons at risk for T. cruzi contribute to the blood supply there is not known.

Study Design and Methods: A questionnaire was used to survey donors in 18 California donor centers for risk factors for T. cruzi infection.

Results: Otherwise eligible allogeneic blood donors (n = 17,521) completed questionnaires. Of this group, 427 (2.4%) had lived in endemic areas for more than 1 year, and 39 of these donors had lived in dwellings with mud walls or thatched roofs. Sixteen donors had received transfusions in endemic areas. Six donors gave a history of Chagas' disease. Fifty-seven donors (0.33% of total) had at least one risk factor for T. cruzi infection. Donors at risk for T. cruzi were found in all 18 centers studied, at a median prevalence of 1 per 340 donors.

Conclusion: Donors at risk for T. cruzi are contributing to the blood supply throughout California. Further consideration should be given to donor screening for this transfusion-transmissible infection.