Dissertation Research: A mechanistic approach to quantifying the costs of parasite communities

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

Most animals, including humans, are infected with multiple parasites simultaneously, but until recently, most infections have primarily been studied in isolation. Emerging evidence from human and wildlife diseases suggests that interactions among parasites co-infecting (i.e., cohabiting) the same host can influence the overall impact on individual host health and disease spread. This research project will examine ways in which co-infecting parasites interact within a host, and investigate the consequences of infection with different combinations of parasites for host health. Free-living (non-parasitic) species often interact directly by competing for food or space, or indirectly via a shared enemy; similarly, communities of co-infecting parasites may compete for limited resources within the host, or attempt to evade host immune defenses triggered by co-occurring parasites. The investigators will use laboratory experiments in mice to manipulate host resources (via nutrition) and parasite community composition (the number and identity of infecting parasites), to test the hypothesis that resource competition and/or predation by the immune system drive changes in interactions between co-infecting parasites with consequences for parasite reproduction, host condition and susceptibility to new parasites. The wealth of immunological and singe-species parasite infection data in laboratory mice provide a strong foundation upon which to build this complex co-infection experiment. Furthermore, the conserved nature of the vertebrate immune system enables broad applicability of study results. Overall, the results of this study will answer fundamental questions about the potential synergistic effects of multiple infections on hosts. This project will provide research experiences for two undergraduate students in addition to enhancing the doctoral research of a graduate student. The principal investigators will also participate in a program that brings hands-on ecological learning to K-12 classrooms in Georgia. Specifically, methods and results from this project will be used to develop a teaching module on the similarity of ecological processes taking place in the external (e.g. competition and predation between species in free-living communities) and internal environments (e.g. competition and immune evasion between parasites within a single host individual).