Too much of a good thing: resource provisioning alters infectious disease dynamics in wildlife

Abstract

Provisioning of abundant food resources in human-altered landscapes can have profound effects on wildlife ecology, with important implications for pathogen transmission. While empirical studies have quantified the effects of provisioning on host behaviour and immunology, the net interactive effect of these components on host-pathogen dynamics is unknown. We use simple compartmental models to investigate how provisioning-induced changes to host demography, contact behaviour and immune defence influence pathogen invasion and persistence. We show that pathogen invasion success and equilibrium prevalence depend critically on how provisioning affects host immune defence and that moderate levels of provisioning can lead to drastically different outcomes of pathogen extinction or maximizing prevalence. These results highlight the need for further empirical studies to fully understand how provisioning affects pathogen transmission in urbanized environments.

Supplementing non‐target taxa: bird feeding alters the local distribution of mammals

“…). Increased concentrations of small mammals at feeder sites will reach an asymptote, however, as larger group sizes may facilitate disease and parasite transmission (Becker and Hall , Sorensen et al. , Forbes et al.…”

“…, Zelenski and Nisbet ). Potential negative implications of bird feeding include increased disease transmission (Becker and Hall , Adelman et al. ), increased risk of predation (Dunn and Tessaglia ) or mortality related to window‐strikes near feeders (Kummer and Bayne ) and changes in evolutionary trajectories (Plummer et al.…”

Prevalence, Genotype Richness, and Coinfection Patterns of Hemotropic Mycoplasmas in Raccoons (Procyon lotor) on Environmentally Protected and Urbanized Barrier Islands

“…For the opposite result in an urban habitat, supplemental feeding (garbage and deliberate feral animal feeding by residents) on St. Simons Island might have led to higher tolerance by raccoons toward conspecific animals, which may reduce aggressive (60) behavior, reducing the likelihood of fighting and hemoplasma transmission through infected blood or saliva. Higher food availability or quality in urban habitats (if raccoons were being fed nutritionally rich supplements, such as cat food) could allow heavier raccoons to mount a more successful immune defense against hemoplasma (61). Additional routes of transmission for hemoplasmas, such as transplacental and transmammary transmission (32), may also influence differences in hemoplasma prevalence, particularly if one population has a different population age structure.…”

Urbanization and Disease Emergence: Dynamics at the Wildlife–Livestock–Human Interface

“…Plowright et al [25] demonstrated that the effects of urban development on these metapopulations, through increased contact with humans and horses, and reduced connectivity between flying fox colonies, could dramatically influence the epidemic dynamics of the virus in flying foxes, and increase the risk of Hendra virus emergence in horses and people. Using mechanistic models, Becker and Hall [82] and Becker et al [78] also demonstrated host demographic, contact and immunological effects of provisioning on R 0 , finding that unless provisioning reduces dietary exposure to pathogens or strongly improves host condition and immunity, increased aggregations of wildlife species dramatically increase pathogen invasion success and long-term prevalence. Environmental stressors such as heavy metal and pesticide pollutants, characteristic of certain urban environments, can further compound these outcomes through their effects on immunological function [83].…”