House Infestation in Latin America

Similar statistics to those in Bolivia (see Appendix 5: House Infestation in Bolivia) are found in endemic areas for Chagas’ disease in other countries of Central and South America (Briceño‑León 1990). For Central America, equally high infestation rates of from 30 to 70 percent are reported for three‑fourths of El Salvador (OPS 1982:3); 25 percent of vinchuca bugs examined there were infected with T. cruzi. In endemic areas of Honduras 15 percent of houses are infested (Ponce 1984), and one vector, T. dimidiata, has spread to urban settings of the capital, where a family of middle‑class professionals reported an acute case of Chagas’ disease in 1989 (Briceño‑León 1990:24). In Costa Rica, 35 percent of the houses are infested, with an average of 22 triatomines per house (Zeledón et al. 1975). Some 31 percent of the triatomines and 12 percent of the people of Costa Rica are infected with T. cruzi. Six percent of the population in Guatemala are infected with T. cruzi; and, in Panama, 3 to 22 percent are infected (WHO 1985). (See Appendix 7.)

In South America, 100 percent of the houses in endemic areas of Argentina are infested with T. cruzi, and 8 percent of children under eight years are infected with Chagas’ disease (Pavlone et al. 1988:103‑5). Around 30 percent of the houses in the northern half of Chile are infested with vinchucas, and 17 percent of the insects carried T. cruzi (Schofield, Apt, and Miles 1982; Flores et al. 1983; Schenone et al. 1985). In Uruguay, Chagas’ infection rates range from 1 to 7 percent for people over twelve years old (Salvatella 1986); and, in Paraguay, all rural areas are endemic for the disease, with infection rate percentages between 22 and 72 percent being reported (Arias et al. 1988; WHO 1985).

Even though Brazil has made a concerted effort to prevent Chagas’ disease, it ranks as one of the most endemic areas in Latin America. About 4.5 percent of the rural population have antibodies against the parasite; 5 million Brazilians have Chagas’ disease and another 25 million are at risk. In the Federal District of Brazil, 4.3 percent of all deaths are attributed to Chagas’ disease (Dias 1987, Pereira 1984).

In Peru, endemic regions are Arequipa, Moquegua, and Tacna, with 12 percent infection rates. Colombia has an even higher infection rate of 16 percent of the houses infested with triatomines, and 30 percent in the Departamento del Norte de Santander.

Venezuela has more than 1 million people with Chagas’ disease. Roberto Briceño‑León (1990) presents a carefully researched analysis of the relationship of housing to Chagas’ disease in Venezuela. Within the last fifty years, Venezuela has had zones where 54 percent of the people were seropositive for Chagas’ disease. One epidemiological study conducted between 1959 and 1965 indicated that within the 35‑to‑44‑year‑old age group 79 percent of those tested had antibodies against T. cruzi, and within the 5‑to‑14‑year‑old age group 15 percent were infected. Fortunately, these figures have dropped significantly since the 1970s because of the use of insecticides: within the group from birth to 9 years of age infection rates have lowered from 20.5 percent in 1959‑1965 to 1.3 percent in 1980‑1982; the rates have dropped from 28.4 percent to 2.7 percent in the group aged from 10 to 19 years. Levels of house infestation have also lowered considerablyfrom 73.2 percent of the huts and 31.1 percent of the houses at the beginning of the program in 1970 to 22.1 percent of the huts and 5.6 percent of the houses being infected in 1976 (Sequeda et al. 1986).

In Venezuela, initial success in the late 1970s led to diminishing insecticide use in the 1980s; it dropped from 74 percent coverage in 1980 to 11 percent in 1984 (Briceño‑León 1990:29). Houses again became increasingly infested, in part because depletion of forests and sylvatic animals in Venezuela pressured triatomines to search for domestic sites for blood meals. This has been demonstrated in the Municipal Bergantín, Estado Anzoátegui, where insecticides were used from 1970 until 1973, followed by three years without spraying insecticides. The rate of house infestation by triatomines increased from 2.8 percent to 11.4 percent, and hut infestation went from 10 percent to 50 percent.