Parasite-mediated changes in host traits can have far-reaching effects. Even sublethal infections affect hosts by increasing energetic costs, altering behavior and immunity, and modifying the ways in which hosts process nutrients. Emerging evidence suggests host diets may mediate effects of sublethal parasitic infections. For example, supplemental nutrition can reduce burdens of helminth infections in mice. Concurrently, parasites can drive changes in host diet and habitat use that may reduce parasite exposure but not improve host health. We propose to investigate how parasite load is associated with host diet using white-footed mice (Peromyscus leucopus) and their helminth parasites as a model system. P. leucopus has become the dominant small mammal species over the last 40 years around UMBS. It experiences sublethal infection by a range of helminth parasites and is a reservoir for several zoonotic pathogens, making its host-parasite dynamics highly relevant to the health of humans and other wildlife. We propose to visit UMBS in summer 2024 to visit potential field sites for studying how diet mediates effects of parasitic infections on P. leucopus and to work with students in the Field Mammalogy course to collect pilot data on P. leucopus parasites and diets between different habitat types.