LB 13-128 - Linking movement and gastrointestinal parasite infections in humans and animals in rural Madagascar

Gastrointestinal parasites infect billions of humans globally and disproportionately affect people living in low and middle-income regions of the world. Despite its ubiquity, multiparasitism and its connections to movement and exposure patterns and sociodemographic factors are less commonly studied than single-host, single-parasite interactions. In this study, we asked whether movement and contact patterns among humans and domestic animals corresponded to zoonotic and non-zoonotic parasite infections in rural Madagascar, and whether high-risk movement patterns were predicted by sociodemographic factors. To address these questions, we conducted an interdisciplinary study at three villages in the SAVA region of northern Madagascar. Participants consented to answer demographic and health surveys, to provide GPS logger data, and to provide a fecal sample for parasite screening. We used DNA metabarcoding to detect a wide range of parasites for humans and 221 domestic animals. We found that multiparasitism was common (nearly 50% prevalence), but co-infection patterns varied across villages. We found that Blastocystis sp. infections were related only to a network of shared households, and that Necator americanus (human hookworm) infections were related to a network of shared forest fragments. We did not find clear movement patterns that related to Ancylostoma ceylanicum (zoonotic hookworm) infections; however, self-reported interactions with dogs was a significant risk factor. In linking these findings to sociodemographic factors, we found that humans at highest risk of hookworm were males with no formal education, and that these individuals were most likely to move furthest across the landscape, including in secondary forest fragments. These findings illustrate the utility of combining parasite-specific transmission potential networks for predicting co-infections at human, domestic animal, and wildlife interfaces.