Authors

A Pedersen¹;  ¹ University of Edinburgh, UK

Discussion

Understanding the relationship between diet availability and parasitic infection in humans and animals is of increasing importance, given rising rates of habitat modification, land-use change and other anthropogenic effects. These changes can alter the distribution, quality and availability of resources, either accidentally (e.g. through consumption of urban waste or agricultural products, the reduction of naturally occurring food sources) or deliberately (e.g. garden bird feeders, tourism, supplemental feeding stations). However, understanding how different diet availability scenarios, either natural or anthropogenic, affect infection levels in wildlife is a major conservation challenge, due to the myriad of ways in which resources affect hosts, both at the individual and population scales. Different resource scenarios can alter a range of biological traits, all of which influence different processes (contact with infective stages, susceptibility, resistance or tolerance to infection, infectivity to other hosts, etc.) that determine parasite infection risk and outcome in different ways. From a series of field and controlled laboratory infection/coinfection experiments, I will demonstrate the effects of nutritional supplementation on both the host (health, behaviour and contacts) and the parasite community (infection, intensity, etc) using a wood mouse system. I will show evidence that nutritional supplementation significantly impacts the gastrointestinal worm Heligomosomoides polygyrus infection intensity and immunity in the wild and lab. In addition, I will present recent results that demonstrate that the composition of the gut microbiome, which is changed by diet, may impact H. polygyrus establishment and resistance. Importantly, I will provide evidence that providing wild mice with a high-quality diet does not always lead to a reduction in parasite infection and intensity, and in contrast sometimes increases the likelihood of infection and even reduces immunoresponsiveness to immunisation. These results highlight how pairing both the lab and natural setting provides a unique and powerful opportunity to understand how nutritional supplementation can impact host-parasite dynamics with implications for better understanding infection, immunity and disease control.