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 sayaña housing with its fortress style of buildings tightly fitted together. The sayaña 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 Pérez Rios 1965).