A population in transition: Health, culture change, and intestinal parasitism among the Tsimane' of lowland Bolivia

Susan N. Tanner
Dept. of Anthropology, University of Michigan
July, 2005


Patterns of human health and disease are shaped by social, economic, and environmental conditions. As a population in transition, the Tsimane' of lowland Bolivia represent one of the many Neotropical groups experiencing rapid changes associated with integration into a larger national culture. In order to understand how health is impacted by acculturation and economic change, this research examines one class of infectious disease: the soil-transmitted helminths. Specifically, it examines two broad questions: (1) how behavioral and economic variation is associated with the distribution of intestinal parasites and (2) whether intestinal parasitism is associated with poor health and nutritional status among the study population. Social and economic integration into the larger national culture of Bolivia was assayed through interviews designed to capture economic status, behavior patterns, education levels, health status, and knowledge of parasites. Anthropometric assessments and fecal samples were used to evaluate health. As predicted, social and economic integration was related to the distribution of soil-transmitted helminths throughout the population. Among adults, measures of education and social integration such as mathematical competency were associated with lower infection levels. Among children and adolescents, household material wealth was inversely related to the number of parasite species subjects carried. There was mixed support for the hypothesized negative relationship between anthropometric status and infection with the soil-transmitted helminths. In this cross- sectional sample, there was no evidence for a relationship between infection level and anthropometric indices of body size among children. However, among adults (especially women) there was a significant negative association between higher infection levels and the Body Mass Index and arm muscularity (Arm Muscle Area). Weak associations are probably due to overall high infection levels (77% hookworm positive). This study demonstrates that, within a group that appears relatively homogenous, behavioral and economic variation affect patterns of infectious disease. Although acculturation and economic improvements are associated with lower infection levels, long term studies are needed to determine if this translates into overall improved health and nutritional status.