Orally acquired Chagas disease: lessons from an urban school outbreak.

The protozoan pathogen Trypanosoma cruzi causes Chagas disease, one of the most important parasitic infections in Latin America. Without effective treatment , infection is usually for life. A likely outcome of infection is heart disease, with electrocardiogram abnormalities and car-diomyopathy. In some geographical areas, this may be complicated by megasyn-dromes, particularly megaesophagus and megacolon [1]. The insect vectors are blood-sucking triatomines. Transmission occurs when insects feed, but the route is precarious and indirect, by contamination of mucous membranes or abraded skin with T. cruzi– infected triatomine feces. The main culprit vectors are a few triatomine species that colonize poor rural dwellings and feed from the inhabitants and from their domestic animals. Despite the recent success of international programs to control such domestic triatomines (notably, Triatoma infestans in the Southern Cone countries of South America), wide regions of domestic transmission remain. Furthermore, T. cruzi is a zoonosis; there are many mammal reservoir hosts (such as opos-sums, armadillos, and rodents), and many triatomine species act as vectors in sylvatic habitats. Such sylvatic bugs pose a threat by replenishing household colonies or by new adaptations to domestic habitats, as well as by occasional incursion of adult insects that fly into houses and may cause sporadic cases of Chagas disease. T. cruzi is not confined to transmission by contamination of the host as the vector feeds, and it has several secondary routes of dissemination. Potential transfusion of contaminated blood demands that all blood donors in areas of endemicity should be screened with serological testing. Similarly, transplant of organs and other tissues may require screening of both donors and recipients, who, if they carry T. cruzi, are liable to experience relapse to an acute infection when immu-nosuppressed. Ideally, the possibility of congenital transmission requires follow up of infants born to seropositive mothers. T. cruzi can travel with Latin American migrants , and these secondary routes allow transmission beyond the established regions of endemic Chagas disease. Thus, T. cruzi infection has been demonstrated among potential blood donors in North America and in Europe, where occasional autochthonous transmission has occurred. As if that were not enough, there is at least 1 more increasingly apparent and important means of T. cruzi dissemination, and that is transmission by the oral route, which is the focus of the report by de Noya et al [2] that appears in this issue of the Journal. Consumption of infective forms of T. cruzi …