Habitat loss and disruption by humans have sent many wildlife populations into decline, but some species can use novel food resources available in human-altered habitats. Resource provisioning is widespread and can be intentional, such as the use of bird feeders or handouts from tourists, or accidental, such as when animals consume agricultural products or household garbage. These resources can alter pathogen transmission in wildlife by changing local host abundance, aggregation, and spatial movements. Resources can also lead to cross-species transmission by bringing wildlife into close contact with humans and domesticated animals. On the other hand, provisioned hosts might experience improved body condition and immune defenses owing to access to reliable food sources. This talk will provide a conceptual framework to address how human-driven changes in food resources interact with the dynamics of infectious diseases in wildlife and to identify key mechanisms by which this occurs.
Findings from a recent meta-analysis characterize the range of outcomes of resource provisioning, and exploration of mathematical models show that the net effect of synergistic and opposing mechanisms can lead to strong nonlinear responses of pathogen invasion and infection prevalence. We next examine three key case studies show how resource provisioning affects human health and wildlife conservation: (i) human planting of exotic milkweeds and butterfly-–parasite interactions; (ii) livestock rearing and the ecology of vampire bat-–rabies interactions; and (iii) human feeding of white ibis and impacts on enteric pathogens in urban parks. These examples indicate that simultaneous depletion of natural food sources, combined with resources provided unintentionally by humans, can affect host ecology and behavior in profound ways, with consequences for pathogen transmission within wildlife populations, and from animals to other species, including humans.