Doctoral Dissertation Research: The Construction of Human Disease Ecologies Through Cultural Transmission: A Nivacle Example

Arizona State University, Scottsdale AZ

Investigators

Abstract

This study examines the role of cultural transmission in the construction of human disease ecologies and the co-evolution of humans and their pathogens using a comparative study of tuberculosis (TB) in Nivacle communities living in the Chaco ecoregion of Paraguay. Drawing on niche construction theory, the study will use a conceptual framework of human disease ecology that includes the various elements of the sociocultural niche, the genetic diversity of TB strains, culturally perceived disease phenotypes, and the moderating effects of other environmental factors such as diet and pathogen load. For the purposes of this study the sociocultural niche is defined as beliefs, behavior, and features of the built and sociopolitical environment that are barriers or enablers to the spread of TB. The Nivacle bear a disproportionately larger burden of TB incidence than do other indigenous groups, mestizos, and Mennonites living in the Chaco. Some Nivacle communities are more integrated into the Mennonite economy than others, and form part of an indigenous-Mennonite cooperative that provides health care support. This dissertation will specifically address: how do different degrees of effective cultural transmission from outside groups change disease ecology in Nivacle communities? This study will compare the TB disease ecologies in two Nivacle communities (one included in the cooperative and one not included) in terms of (1) the sociocultural niche, (2) the genetic diversity of tuberculosis, and (3) the culturally perceived disease phenotype exhibited by sick individuals. In phase I of the study, the Co-PI will conduct censuses of the communities and open-ended ethnographic interviews with key informants about the cultural perceptions of TB, the experiences of TB patients, and the social response to illness and access to healthcare in general. In phase II, a stratified case-control study of 200 individuals in these communities will be undertaken using a variety of methods, including a locally derived TB symptom survey, time allocation observations, quantitative PCR of TB DNA, anthropometrics, and analysis of fecal samples for helminth loads, to quantify the relationships between the variables of interest. This study will contribute to our understanding of how cultural transmission influences the way humans construct their disease ecologies and host-pathogen co-evolution. Cultural and linguistic barriers, in combination with inefficient diagnostics and 6-12 month treatment protocols, put indigenous populations at high risk of emergent strains of MDR-TB. Clearly, cultural transmission of knowledge about the disease, its causes, treatment, and prevention, as well as cultural "validation" of that knowledge creates selective pressures that act on the host and pathogen simultaneously and synergistically. The results of this study will be used to plan a longitudinal panel study of the coevolution of the Nivacle disease ecologies and tuberculosis in the Paraguayan Chaco. The comparison of these two communities with different levels of effective cultural transmission is also relevant to scholars of social change and development and applied health interventions. This research will be one of the foci of a large international research network that involves researchers from Paraguay and the United States. The Co-PI will be training and receiving training from Latin American research scientists and students working in the Paraguayan Chaco region. The Co-PI will also be training an indigenous person in ethnographic interviewing and anthropometric techniques. Additionally, the Co-PI will be collaborating with the Mariscal regional hospital for Boqueron, which has agreed to share hospital records in assistance of the research project. This partnership ensures that the study results will reach the appropriate persons to create interventions, and may help improve community-based initiatives to combat TB and the rise of antibiotic resistance in Nivacle and other small scale indigenous communities that disproportionately suffer from the disease.