The effects of species-level heterogeneity on disease dynamics

What is it and why do we care?

Many pathogens of concern in humans, livestock, and wildlife infect multiple host species within a community. Within a community, particular host species contribute differently to infection dynamics. For example, some species can act as diluter species, and reduce the overall transmission of a pathogen in the community. In contrast, some species can act as maintenance or reservoir species, with the capacity to independently maintain the pathogen and contribute to infection in other focal hosts. In addition, some species can act as spillover species, where non-zero infection prevalence is simply a result of transmission due to other species in the community. Identifying the role of particular host species in a community, such as those acting as maintenance and reservoir species, can help reduce transmission in the community as a whole with targeted management of a single species. This approach has been successfully applied, for example, to reduce the prevalence of rabies in mammal communities in North America, Europe, and Africa.

What are we working on?

Maintenance species in host-pathogen systems

Identifying which species are maintenance species, diluter species, and spillover species provides critical information for informed disease management. However, despite the tendency to classify species’ maintenance potential as an intrinsic attribute, ecological context matters. In other words, depending on when and where a species is found, it may or may not consistently act as a maintenance species. Identifying the extent to which maintenance potential is consistent in space and time is critical for identify whether disease management (e.g., culling, treatment, etc.) should focus on a particular species or a particular location.

A key question that we are asking in the lab is: How consistent is the ability of a species to maintain a pathogen in a community through space and time? In other words, once a species is a maintenance species, is it always a maintenance species? We are addressing this question in multi-species amphibian communities in California and the Eastern United States. We have also previously explored this question in mammal communities infected with bovine tuberculosis in Michigan.

Here is some of our previous work on maintenance species in multi-host communities: Wilber et al. 2019, Journal of Applied Ecology; Wilber et al. 2021, Ecology Letters