Mouse Disease Profiling

The role of pathogens in regulating population dynamics

Background

The introduced house mouse (Mus musculus domesticus) in Australia undergoes large fluctuations in numbers occasionally resulting in outbreaks (mouse plagues) leading to significant economic losses due to damage to grain crops and infrastructure, direct contamination of feed, and transmission of rodent-borne diseases. However, the extent of pathogens carried by wild mice and the potential correlation with population dynamics of mice in Australia is unknown.

Via applying modern high-resolution meta-transcriptomic approaches, we can discover known and unknown pathogens carried by feral pest rodent species in Australia’s cropping regions. Utilising meta-transcriptomics in this project, we aim to identify novel emerging pathogens, elucidate the complex co-infections and coevolution within microbes and their rodent hosts as well as how they regulate the population dynamics in the wild. This approach will improve our understanding of rodent management and enhance targeted surveillance in response to emerging infectious disease events that would have implications for ecology, agriculture, and public health in Australia.

Aims

In this project, we aim to profile the pathogens present in Australian wild mice during ‘mouse plague’ population densities, and then temporally as mouse populations decrease, to investigate whether mouse population cycles are associated with changes in pathogen dynamics. At the same time, we will identify whether Australian wild mice carry pathogens that may pose a risk either to humans, or to other livestock, companion animals, or wildlife species. Specifically, this project will answer:

  1. What pathogens are present in wild mice and how does this change over time? There is currently a lot of speculation in the media around mice transmitting diseases to either humans or other animals. However, these speculations are not supported by scientific evidence. This project will tell us which pathogens are present in wild mice and provide an indication of the prevalence of these pathogens in mouse populations across Australian grain cropping regions, which will provide sound evidence on the public and animal health risks posed by wild mice. One tangible outcome of this information would be guidance on contaminated fodder management. Under current practices, fodder that has been infested with mice is commonly destroyed. If mice do not pose a disease risk for livestock fodder may not need to be destroyed. This would result in considerable economic savings to growers.
  2. Can we correlate changes in mouse population dynamics with changes in pathogen composition or abundance? The contribution of disease to the mouse boom-and-bust population cycles has not been thoroughly investigated, though anecdotal evidence suggests a higher disease prevalence in the late phase of mouse plagues. If disease is found to be involved in population crashes, or indeed a reduction in disease pressure is associated with the initial boom of mouse plagues, this would lead to additional tools to better predict population build ups and crashes. This information would enable the grains industry and growers to make informed decisions about management.
  3. Identification of candidate biocide agents. Mouse plagues in broadacre farming are currently managed primarily through the use of a single agent (zinc phosphide baits). There has been ongoing interest in the potential for improved mouse management using biocontrols (new agents that will spread naturally and suppress populations) or biocides (new or existing agents that will act locally after a release to suppress numbers short term), based on successes in other vertebrate pests such as RHDV in rabbits. The first step to identifying suitable candidate biocontrols and biocides is to know what pathogens are already present in target populations. This project will directly address this question, guiding future work into identifying and characterising candidate biocontrol agents.

Research activities

Publications

Chang, W.-S., & Wille, M. (2023). Winter is coming—The role of seasonality through the lens of the rodent virome. Molecular Ecology, 32, 4709–4712. https://doi.org/10.1111/mec.17078

White, J., Taylor, J., Brown, R P., Henry, S., Carter, L., Mankad, A., Chang, W.-S., Stanley, P., Collins, K., Durrheim N D., Thompson, K. (2024) The New South Wales Mouse Plague 2020-2021: A One Health description. One Health, 18, 100753. https://doi.org/10.1016/j.onehlt.2024.100753