Interkingdom Community Interactions in Disease Ecology

Abstract

A key tenet of community ecology is the interactions of individual organisms contribute to the ecological structure and function of ecosystems. Within these networks of interacting organisms are those taxa important for human and animal health: disease systems defined by combinations of host, pathogen, reservoir, and vector or a subset of these components. While the simplest disease system is that of the host and pathogen, more complex systems include the direct interactions of a pathogen with other hosts and the microbial communities of those hosts, reservoirs, and sometimes vectors. Each of these disease system components is made up of species that directly and indirectly interact with other species in ways that affect their individual fitness, population biology, and role in communities of the ecosystem. This chapter recognizes the direct interactions of those species that make up the primary components of disease systems; however, the focus and examples provided relate to the more indirect interkingdom (or domain) interactions that impact disease system components. The examples provided include how microbial communities mediate invertebrate and vertebrate fitness and behavior, often in systems where the hosts play important roles in pathogen transmission and disease emergence. The potential mechanisms of these interkingdom interactions are also developed in detail, as the mechanisms of such interactions are likely the target of future studies that could directly inform disease management strategies. Based on these examples and mechanisms, the existing literature suggests there are likely undiscovered and complex interactions of species within communities that affect disease systems.