DISSERTATION RESEARCH: The effects of multi-species interactions on the community structure of parasites

Princeton University, Princeton NJ

Investigators

Abstract

Research on infectious diseases typically focuses on single-parasite infections. However, most individuals are co-infected with multiple parasite species, and parasites interact with one another within hosts. These interactions may profoundly impact the outcome of parasite infections. For example, parasites that directly compete with one another for the same resource may inhibit each other's persistence. This project will examine the direct and indirect interactions of multiple intestinal parasites in school children in southern Vietnam. The prevalence of parasites will be quantified and interactions examined through immunological assays. This research will expand from the idea that hosts harbor only one infection at a time and will provide a better understanding of the patterns and processes shaping within-host parasite communities. Ultimately, by considering hosts infected with multiple parasite species, this research may reshape the design and implementation of global health interventions against intestinal parasites; in the short term it will aid in local public health efforts in Vietnam. The project will also advance the field of disease ecology by the study of population-level processes. It will support the training of a graduate student while increasing international colloboration. Compared to single-parasite infections, multi-species infection interactions can profoundly impact host fitness, parasite transmission, and disease dynamics in unexpected ways. This project will investigate the effects of parasitic helminth infections on subsequent colonization by diarrheal pathogens. The first step will determine the composition of parasite communities using PCR on stool samples. The second step will use sequence the 16S rRNA gene to generate data on the taxonomy of the gut microbiota, and blood and stool samples will be analyzed for immune markers. As helminth infections occur in over 2 billion people worldwide, understanding diarrheal diseases in the context of helminth co-infections may help explain the heterogeneity in parasite burden and disease severity found amongst individual hosts and shape patterns of disease dynamics at the population level. Knowledge about such within-host parasite interactions will also have important implications for studies in disease ecology and will be important for effective management of human and animal diseases in co-infected populations. This project will foster collaborations between U.S., U.K., and Vietnamese universities and will train students in parasitological, immunological, and ecological methods. The overall study findings will be published in both English and Vietnamese and will also be conveyed to the Vietnamese community and public health system through outreach programs.