Epidemiological Reflections

T. cruzi is a silent traveler through vinchucas that has infected 1.5 million people in Bolivia and some 17 million more in other Latin American countries (see Appendix 6). T. cruzi infects people through contamination, blood transfusions, and congenital infection. Vinchucas, T. infestans, have adopted domestic and peridomestic habitats, finding run‑down houses crowded with people and animals very suitable for shelter and food. Vinchucas follow migrants and animals to the cities. For the prevention as well as the treatment of Chagas’ disease, the chain of life‑stages of the parasite needs to be broken at some point. The possibilities include the elimination of triatomine insects, which is highly unlikely in certain places; prevention of transmission through the bite of the triatomines by means of improved housing, which is presently being done but is very costly; and through vaccinations to block some transformation of epimastigotes to metacyclic trypomastigotes to amastigotes to blood‑form trypomastigotes, which is discussed in Appendix 3: Immunization Against T. cruzi.

Even though measures are taken to destroy vinchucas and purify blood banks, the congenital transmission of Chagas’ disease will still occur in Bolivia due to the large percentage (50 percent) of women who are infected with T. cruzi transmitting the parasite during pregnancy. The incidence of congenital transmission of Chagas’ disease is 10 percent in Bolivia, which is double that found in Argentina and Brazil, but this may be due to the fact that the latter two countries did not consider newborns in their counts. Preventative measures that relate to early detection of the infection and the subsequent treatment of newborns are required.

T. cruzi can travel in blood and organs to infect people in nonendemic regions. It travels with women as they migrate from rural to urban areas and from Bolivia to other countries of the world, and it is passed along to their children, usually for two generations. The transmission of T. cruzi is no longer limited to Latin America and the environments of its primary vectors, triatomines. It is becoming a worldwide problem. The silent traveler has arrived on distant shores.