The Kiss of Death

in their baggage to nonendemic areas; infected peasants transfer T. cruzi in their blood to uninfected vinchucas in new regions. Peasants sell their blood to unwary buyers, passing the disease through blood transfusions. Residentes (urbanites) visit relatives in rural areas, where they become infected and return as hosts for Chagas’ disease in the cities. Chagas’ disease also has been imported into France and the United States (Brisseu et al. 1988; Kirchhoff, Gam, and Gilliam 1987).

Peasants migrate because their land has been sold, worn out, or expropriated. Some are ignorant of principles of sustainable agriculture; others lack money to improve productivity. Some Bolivians travel from the Altiplano to agricultural zones of Chile to pick fruit during the dry season and to pick coca leaves in the sub-Andean regions of the Yungas during the wet season. Many peasant families have daughters who work as maids for families in Cochabamba, Santa Cruz, and La Paz. Others migrate to cities to find employment in construction and domestic labor markets.

When peasants first settle an area they cut the brush and trees to farm the land. Vinchucas are forced out of their nests in bushes and trees where they have fed upon birds and rodents. They move into the corrals and huts of the invading peasants. The Department of Tarija, Bolivia, has suffered especially, with high percentages of vinchuca infestation reported in corrals (61.6 percent) and ovens (60.2 percent). This explains its high infestation rate (78.2 percent), infected vinchucas (50 percent), and people with Chagas’ disease (60.6 percent).

Temporary Housing

Migratory peasants generally do not have the time and money to build a house that adequately protects them from the environment, so they construct temporary housing, which is often nothing more than a shack made from refuse. Cochabamba and Sucre had high numbers of refuse housing (41 and 44 percent, respectively), which are readily infested. Peasants invest little in shacks built on land that they do not own, may be evicted from, and are unable to sell. Outside of Cochabamba, peasants objected to participating in a housing-improvement program because they believed that once their houses were improved they would be confiscated and sold to someone else.

Peasants sometimes sleep in temporary shelters closer to their fields, which are becoming increasingly distant from their homes as traditional farming lands become barren. Peasants in these areas rapidly put together lean-tos of thatch and branches where they spend nights guarding their fields. This presents an additional problem: the peasant’s main house may be vinchuca-proofed, but peasants remain at risk when they sleep in the fields.

The displacement of rural people is a growing social concern throughout Latin America. It has been brought about by overpopulation, depletion of natural resources, growth of corporations, and demand for mobile work forces. Migrating peasants essentially become foragers and gatherers. Frequent dislocation requires that they construct homes with available materials and that they invest little in nonmoveable property.[42]

Colonization

Since the 1953 Bolivian agrarian reform, national policies have encouraged colonization of unpopulated areas in Bolivia. The general movement has been away from the Altiplano and higher altitudes towards settlement in the lower regions of the Alto-Beni and Santa Cruz. Since the closing of mines in the 1980s, there has been an economic shift from Andean mining to tropical agriculture. These changes have brought about an increase in Chagas’ disease.

Aymaras and Quechuas have lived in the higher mountains and valleys for millennia and are referred to as Qollas. Guarani tribes of many ethnic groups at lower altitudes are referred to as Cambas. Qollas and Cambas consider each other as inferior; for example, some Cambas extend their biases, teaching their parrots to cry out every time a Qolla passes, “Phew, what a stink.” Qolla peasants, poor as they may be, consider themselves descendants of the Incas and heirs of that civilization.

There has been a mixing of Qollas and Cambas through colonization, more on the part of Qollas, who have settled in large numbers in the Departments of Santa Cruz and the Alto Beni. One consequence relating to the spread of Chagas’ disease has been that the Qollas have brought their higher-altitude style of housing to these warmer and moist regions: thickly walled adobe construction, small openings for doors and windows, and thatched roofingall of which hold the heat in and the cold out. The results are favorable for vinchucas: hot houses with little light and ventilation. The architectural style of Cambas’ houses is characterized by a series of separated rooms around a central courtyard (oca). Oca housing allows more space between the buildings, which are separated from each other by outside work areas at the sides and within the center. This is different from sayana housing with its fortress style of buildings tightly fitted together. The sayana is metaphorically an extension of the earth, a mediator between that which is above and below, whereas the oca is a courtyard in the forest.

Oca houses also have become centers for vinchucas, partially because of colonization, which has brought crowding. People have moved their corrals, chicken coops, and storage areas closer together, in part to protect their animals from predators and thieves. However, this has also made it easier for vinchucas to get from the corrals to the dormitories.

National policy encourages peasants to live in clustered settlements to facilitate schooling, political consolidation, and the building of water and sewage systems. This in turn has created some unhygienic conditions, such as increased infestation, contaminated water supplies, and backed-up sewage systems. Health officials favor the development of water and sewage systems, because this is a marker most noted in world health standards, and Bolivian officials want to be recognized for improving their nation’s health, especially now that they want to attract tourism.

Interestingly and fortunately, Chagas’ disease has had little effect on nomadic Indian populations in lowland areas of the Amazon Basin in Bolivia and Brazil, perhaps because they do not live for prolonged periods in the same dwellings (Coimbra 1992). Within the Department of the Beni, Bolivia, there are thirty-five ethnic groups. However, seminomadic and sedentary tribes are being infected with Chagas’ disease at extraordinary rates, in part because their huts are made of thatched roofs and palm walls. For example, one community of Tupi Guarani Indians in Bolivia has a 100 percent rate of infection. Moreover, Tupi Guarani within the Department of Tarija will be seriously affected by the construction of a dam on the Pilcomayo River that will flood much of their land, further forcing them to become sedentary farmers.

Thatched roofs are used extensively throughout the Andean and tropical regions of Bolivia. Thatched roofs provide habitat for triatomines, especially for sylvatic species accustomed to living in trees, such as Rhodnius prolixus, whose preferred forest habitat is the branches of palm trees. When palm trees are cut down, this vector travels with the leaves used to weave roofs, and spaces within the woven palms provide homes for these insects (Gamboa and Perez Rios 1965).

Urbanization: Class and Ethnic Distinctions

According to the census of 1950, 74 percent of the Bolivian population lived in rural areas and 26 percent