aggravated the infection (Di Primio 1971). Trypanosomes can be found in the saliva and urine of animals suffering from acute parasitemia. This constitutes an infective risk for humans working with these animals (Marsden and Hagstrom 1968).
A third instance was in Belem, Para, Brazil, at the mouth of the Amazon, where human Chagas’ disease is rare (Lainson et al. 1979) because only sylvatic species of bugs in this area are known to be infected. It is possible that an infected bug entered the house and fell in a cold soup customarily prepared (Lainson et al. 1980) and infected it with T. cruzi. Because contamination is the major route of transmission, many other possibilities exist for humans coming in contact with T. cruzi through vinchuca feces falling from the ceiling, getting into clothing, and being deposited on tools, among other things. As already mentioned, the periodic washing of the body and clothes is important in combatting the disease, as are good house hygienic practices.
Animals can transmit T. cruzi to humans by licking their skin, and nursing mothers can pass it on to their babies in lactation, possibly through the milk but more likely through sores or inflammations on the breast (Carrasco and Antezana 1991). The parasite’s presence in maternal milk has been confirmed by Medina (1983), but the incidence of transmission by this route has not been reported, probably due to the problem of differentiating it from congenital transmission (Moya 1994).
Transmission by breast-feeding appears to be highly unlikely, and infected mothers need not restrict breast-feeding their infants (WHO 1991:33). This conclusion was based on a systematic parasitological study of 100 milk, or colostrum, samples from seventy-eight mothers with chronic Chagas’ disease in Bahia, Brazil. Even though five mothers had detectable parasitemia, all samples were negative (Bittencourt et al. 1988). In another study in Cordoba, Argentina, and Santa Cruz, Bolivia, ninety-seven children (100 percent of the sample) born free of the infection from infected mothers and subsequently breast-fed tested serologically negative (WHO 1991:33).
Organ transplants from infected donors is an increasing route of T. cruzi transmission for recipients in the United States and Europe. There is an increasing number of organs being sold through the “black market” to patients in the United States from Latin American countries. Americans also travel to clinics in Latin America for organ transplants. Kidney transplants have been shown to be a source of T. cruzi infection, and organ recipients have developed acute episodes of Chagas’ disease (Chocair et al. 1981). In certain transplants, fatality has been attributed to donated organs infected with T. cruzi, because recipients are under immunosuppressive therapy (WHO 1991:34). Conversely, Chagas’ disease patients who receive organ transplants can suffer exacerbation of the infection when given immunosuppressive treatment (Leiguarda et al. 1990).
Laboratories treat T. cruzi with respect. It is the most infectious of the human blood protozoa. By 1976 more than fifty lab technicians had been infected with Chagas’ disease; they suffered meningoencephalitis and megasyndromes (Marsden 1976). Since this time, technicians have learned how to better handle high-risk organisms, but certain research hospitals still refuse to do research on T. cruzi because of its risk factor. Laboratory infections are usually due to punctures with infected needles, contact with contaminated materials, breathing T. cruzi cultures while pipetting, and splashing T. cruzi suspensions on the conjunctivae. Measures for prevention and control are outlined in WHO (1991).
Laboratories in Bolivia present great risks for contracting Chagas’ disease because of their often rudimentary facilities, inadequately trained staff, and insufficient funds to provide protective measures. The exception is the Instituto Boliviano de Biologia de Altura (IBBA), located in La Paz and affiliated with the Pasteur Institute in Paris. Eminent French and Bolivian scientists direct this research laboratory and have done leading work on parasitology. Other, much less developed, laboratories are under control of the Secretaria Nacional de Salud and are funded with minimal budgets. Nonetheless, technicians make do. One technician observed that he was not worried about Chagas’ disease, being already infectedwhich perhaps is the case for many Bolivian researchers.
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.
CHAPTER FIVE
Colico miserere: Enlarged Colon
Chagas’ disease is an elusive target for medical practitioners. It has a diffuse symptomology, if any, until the classic chronic stage, and its clinical symptoms could result from a number of other diseases and causes. It cannot be cured in its advanced stages. It is an autoimmune disease. Moreover, in Bolivia and most other places, Chagas’ disease is not well known and patients are rarely tested for it. Biomedical and ethnomedical practitioners treat its symptoms with a combination of home remedies, herbs, surgical practices, and rituals. Cultural and social interpretations of its symptoms sometimes delay medical treatment, but they help Bolivians understand in meaningful terms the suffering it causes. These interpretations can also be used to educate Bolivians about Chagas’ disease.
Juana is a Quechua-speaking peasant of the Calcha ethnic group in the north of Potosi. She and several
