Climate warming drives pulsed resources and disease outbreak risk.

Abstract

Climate influences the risk of disease transmission and spread through its direct effects on the survival and reproduction of hosts and pathogens. However, the indirect influences of climate variation (i.e. those mediated by food resources on host demography) are often neglected. Pulsed resources produced by oak trees in temperate forests constitute important resources for seed consumers and strongly depend on temperature. Using an individual-based model, we provide a theoretical exploration of the influence of climate warming on the dynamics of the African swine fever (ASF) in the seed consumer wild boar (Sus scrofa), considering both direct and indirect temperature effects. We show that climate warming directly decreases the persistence of the virus in the environment, but also increases the production of acorns, with cascading effects on the seed consumer host species. Integrating these climatic effects suggests a decrease of ASF spread under future warmer conditions. Importantly, food-mediated indirect effects of climate may outweigh direct effects, reversing, in some situations, the predictions of epidemic dynamics under climate change. This shows that anticipating future epidemic risks requires a deep understanding of ecological systems, including all direct and indirect climatic effects.