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.
This study focused on the role of cultural transmission (the transfer of beliefs, behaviors, and values from one cultural group to another) in the disease ecology of tuberculosis (TB) in indigenous communities of the Paraguayan Chaco. The cultural model of TB held by a community is important because it contributes to: the ability to identify symptoms and know when to seek treatment, willingness to seek treatment and persistence in the treatment program, and social acceptance or stigma of TB patients. Cultural and linguistic barriers, in combination with inefficient diagnostics and minimum six month treatment protocols put indigenous populations at high risk of emergent strains of antibiotic resistant TB. The Chaco is a sparsely populated, semi-arid plain in eastern Paraguay that has limited transportation and communication infrastructure. We hypothesized that more isolated communities are less exposed to and less familiar with biomedical ideas about tuberculosis. We compared two Nivaclé communities to control for culture; one that was relatively isolated and one that was more integrated with transportation and communication networks. Contrary to expectations, the more isolated community had a greater diversity of sources of information about TB than the more integrated community. The cultural models of TB (that is, beliefs about the causes, symptoms, treatment, and appropriate responses to TB) in both the communities deviated from the biomedical model of TB held by local healthcare workers, but the isolated community’s model drew more from the biomedical model. Our second hypothesis was that communities with more cultural transmission from outside institutions would have greater public health infrastructure (including health posts, wells, and latrines), greater adoption of health protective behaviors like hand washing, and relatively fewer illnesses. Neither knowledge of TB nor degree of isolation was tied to public health infrastructure. We did fecal sampling in three communities (two Nivaclé and one Angaité) to examine the prevalence of intestinal parasites and their association with environmental and behavioral factors. Despite having a more secure water source, the Angaité community had a higher percentage of participants test positive for Giardia lamblia in their fecal samples; possibly because Angaité respondents were significantly less likely than Nivaclé respondents to report using soap when washing their hands. This project also collected cheek swabs from study participants to test for exposure to Mycobacterium tuberculosis DNA. We expected that the more integrated communities would be exposed to a greater diversity of TB strains, and the more isolated communities would be more likely to have antibiotic resistant TB strains due to difficulties adhering to treatment. Only two of the 152 cheek swabs we collected in 2011 were positive for TB DNA. With additional support from the Wenner Gren Foundation, another set of cheek swabs was collected in 2012 and these are still undergoing analysis. Intellectual Merit: Human disease ecology is the study of the interactions between the behavior and ecology of humans with the biology of pathogens, and how these interactions lead to different disease patterns in populations. Because these patterns are outcomes of both biological and sociocultural factors, this project combined research methods from several disciplines to meet its objectives, including sociocultural and physical anthropology, epidemiology, and microbiology. We anticipate that the results of this interdisciplinary approach will be interesting to each of these disciplines. The Co-PI plans to conduct follow-up studies to examine the change in disease ecologies and tuberculosis over time in the Paraguayan Chaco. The results of this research are likely to impact our understanding of how tuberculosis persists in isolated settings and will have important public health implications. The research conducted to date provided very rich and diverse data sets and an important baseline of information about the disease ecology of TB. Some of the data sets that are currently undergoing or awaiting analysis include: household and individual level health risk factors surveys, symptom surveys, time allocation observations, social network data, 24 hours dietary recall surveys, and 25 years of archival health records. Broader Impacts: The Co-PI trained seven indigenous Nivaclé women and four Paraguayans in a variety of field methods, and three undergraduate students from Arizona State University did research apprenticeships with this project. The investigators collaborated with local healthcare workers from two Health Regions and the National TB Program in Paraguay to share information, assist local healthcare workers with screening persons for TB, and ensure that study participants received appropriate medical attention. The project allowed for an accurate laboratory diagnosis and treatment of participants' intestinal complaints and determined the prevalence rates for several infectious parasites in the study communities. Furthermore, health education about tuberculosis and intestinal parasites was integrated with study activities. Normal 0 false false false EN-US X-NONE X-NONE
