Based on an analysis of AIDS cases among the Xokléng Indians in 1988, this article relates the illness phenomenon to socio-cultural disruptions and transformations in this indigenous group's universe, focusing on the history of their contact with Brazilian national society. The analysis and interpretation of this relationship are based on anthropological theories about the centrality of the body, corporeality, and degenerative bodily processes in Brazilian indigenous societies, according to which the body, society, and macro-situational elements are articulated by social praxis, and should thus be related in socio-anthropological studies of health-illness phenomena. The article briefly describes the history of epidemics emerging from contact and attempts to relate them to specific historical contexts. Ethnomedical categories, cosmology, and Xokléng concepts of corporeality are related to their social organization, which are thus connected to the AIDS cases. The latter are presented with a special focus on the relationship between their emergence and the changes occurring in the Xokléng world with the construction of a dam bordering on their land.