American trypanosomiasis (Chagas' disease) and blood banking in Mexico City: Seroprevalence and its potential transfusional transmission risk

Background. American trypanosomiasis (Chagas' disease), an anthropozoonosis fairly common in rural Latin America, has become an urban disease due to c ontinuous migration, intra- and internationally. Blood transfusion, the sec ond important pathway for transmission, increases its impact, Recognition o f seropositive subjects among blood donors is now recommended, and clinical and serological screening enforced. Maneuvers to inactivate or remove Tryp anosoma cruzi present in collected blood are recommended. Methods, We surveyed voluntary donors at the National Institute of Cardiolo gy in Mexico City in search of anti-T. cruzi by indirect immunofluorescence , ELISA, and Western blot analysis. Seropositive donors were identified and tested for immunoglobulin. We used types and fractions of donated blood to extract DNA and perform the PCR technique using kinetoplast primers seekin g parasite DNA in blood, Results, After 3,300 donors were screened, we identified 10 seropositive su bjects (0.3%). These subjects were considered as indeterminate chagasic pat ients, came mainly from rural areas, and had IgG (100%) and IgA (30%) antib odies against a crude extract as well as a recombinant T. cruzi antigen. Id entification of parasite DNA in red cell and platelet fraction was achieved from eight blood units. Conclusions. The present data provide evidence that blood donors at an urba n hospital are seropositive for T. cruzi and at least 50% of donors carry t he parasite potentially able to transmit T. cruzi in their cellular blood p roducts, Serological screening should be included in routine blood-banking, It is also necessary to adopt measures to inactivate or eliminate organism s in donated blood. (C) 1999 IMSS. Published by Elsevier Science Inc.