© 2015 by Griffith Wildlife Disease Ecology Group

 

Dynamics of bats and pathogens

 

Bats are increasingly being recognised as reservoirs of viruses that may be transmitted to humans (zoonoses).

 

There is significant global interest in understanding the dynamics of these viruses within bat populations, and circumstances under which these viruses are able to transmit, or ‘spillover’ to humans.

 

Hendra virus is endemic in Australian flying foxes and can be fatal to horses and humans. Hendra virus infection dynamics within bat populations are poorly understood and therefore spillover to horses is difficult to predict. 

A fundamental knowledge gap in Hendra virus research is the mechanism driving pulses of viral shedding from bats. Suboptimal uptake of a Hendra virus vaccine for horses has resulted in patchy coverage and spillovers have continued. Improved predictive abilities would mitigate the significant effects that each spillover event has, namely, equine deaths, risk to human life, widespread distress and fear among horse owners and the general public, and expensive biosecurity containment efforts.

We are investigating the influence of broad habitat changes on spillover events. Ongoing loss of small patches of winter-flowering habitat that are needed to sustain bat migration has led to increased numbers of bats moving into towns and cities in eastern Australia. We believe chronic and acute food shortages are affecting bat health and feeding habits, ultimately leading to increased spillover risk to horses. Our international collaboration of researchers (see here) hopes to dig into these hypotheses in more depth, and ultimately aim to commence a long-term habitat restoration project to reverse some of these trends.

This work is being extended in our more recently funded project "Preventing emergence and spill over of bat viruses in high-risk global hotspots". This project also addresses the dynamics of bat movement and health, bat virus transmission, and human responses to bats and spill over, but will span five continents and involve 25 senior investigators from 14 institutions. Together, with our combined expertise in ecology, physiology, epidemiology, virology, immunology, behavioural ecology, veterinary medicine, political science, anthropology, and mathematical modelling, we aim to address each of the factors that must align to cause zoonotic transmission of viruses from bats to humans and develop preemptive solutions.

 

Like all natural host-pathogen systems, Hendra virus and fruit bat ecologies are complex and intractable to analyse as a whole. Compartmentalisation, simplifying assumptions and a combination of field, laboratory and modelling studies are required to gain insight.

 

More details on the aims of this work can be found here.

 

Other aims within our bat work include:

  • Investigate the prevalence of multiple bat paramyxoviruses, whether specific host-viral relationships exist, and if synchronous shedding pulses of multiple viruses occur - ultimately reconsidering Hendra virus as part of a multi-host-multi-virus community (see more here).

Our work is funded by

 

The US National Science Foundation's Dynamics of Coupled Natural and Human Systems (CNH) grant and Alison Peel's Queensland Government Accelerate Early Career Research Fellowship "Bridging the gaps in Hendra virus research".

Collaborators

 

Our major collaborators are Associate Professor Raina Plowright and Dr Peggy Eby. We collaborate with a wide range of international collaborators (see here). Within Australia we collaborate with Queensland Department of Agriculture and Fisheries, New South Wales Department of Primary Industries, New South Wales Local Land Services, and The Emerging Zoonotic Disease Group at the CSIRO Australian Animal Health Laboratory (AAHL).

 

Useful references

 

  • Kessler, M. K., Becker, D. J., Peel, A. J., Justice, N. V., Lunn, T., Crowley, D. E., Jones, D.N., Eby, P., Sánchez, C.A., Plowright, R.K. (2018) Changing resource landscapes and spillover of henipaviruses. Annals of the New York Academy of Sciences, 112, 91. (link)

  • Giles, J. R., Peel, A. J., Wells, K., Plowright, R. K., McCallum, H., & Restif, O. (2018, August 28) Optimizing non-invasive sampling of an infectious bat virus. bioRxiv. (link)

  • Peel, A. J., Baker, K. S., Hayman, D. T. S., Broder, C. C., Cunningham, A. A., Fooks, A. R., Garnier, R., Wood, J. L. N., and Restif, O.  (2018) Support for viral persistence in bats from age-specific serology and models of maternal immunity. Scientific Reports, 8(1), e0004796. (link)

  • Giles, J.R., Eby, P., Parry, H., Peel, A.J., Plowright, R.K., Westcott, D.A. & McCallum, H. (2018) Environmental drivers of spatiotemporal foraging intensity in fruit bats and implications for Hendra virus ecology. Scientific Reports, 8: 9555. (link)

  • Plowright, R. K., Parrish C, McCallum H, J. Hudson P, I. Ko A, L. Graham A, O. Lloyd-Smith J. (2017) Pathways to zoonotic spillover. Nature Reviews Microbiology 15:502-510. (link)

  • Paez, D.J., Giles, J., McCallum, H., Field, H.E., Jordan, D., Peel, A.J. & Plowright, R.K. (2017) Conditions affecting the timing and magnitude of Hendra virus shedding across pteropodid bat populations in Australia. Epidemiology and Infection, 57, 1–11. (link)

  • Giles, J. R., R. K. Plowright, P. Eby, A. J. Peel, and H. McCallum. (2016) Models of Eucalypt phenology predict bat population flux. Ecology and evolution. doi:10.1002/ece3.2382 (link)

  • Plowright, R. K., A. J. Peel, D. G. Streicker, A. Gilbert, H. McCallum, J. L. N. Wood, M. L. Baker, and O. Restif. (2016) Transmission or within-host dynamics driving pulses of zoonotic viruses in reservoir-host populations. PLoS Neglected Tropical Diseases 10: e0004796. (link)

  • Plowright, R. K., P. Eby, P. J. Hudson, I. L. Smith, D. Westcott, W. L. Bryden, D. Middleton, P. A. Reid, R. A. McFarlane, G. Martin, G. M. Tabor, L. F. Skerratt, D. L. Anderson, G. Crameri, D. Quammen, D. Jordan, P. Freeman, L. Wang, J. H. Epstein, G. A. Marsh, N. Y. Kung, and H. McCallum (2015) Ecological dynamics of emerging bat virus spillover. Proceedings of the Royal Society B-Biological Sciences. 282: 20142124. (link)

  • Martin, G., Plowright, R. K., C. Chen, D. Kault, P. Selleck, and L. Skerratt (2015) Hendra virus survival does not explain spillover patterns and implicates relatively direct transmission routes from flying foxes to horses. Journal of General Virology. doi:10.1099/vir.0.000073 (link)

  • Plowright, R. K., Foley, P., Field, H. E., Dobson, A. P., Foley, J. E., Eby, P., & Daszak, P. (2011) Urban habituation, ecological connectivity and epidemic dampening: the emergence of Hendra virus from flying foxes (Pteropus spp.). Proceedings of the Royal Society B: Biological Sciences, 278(1725), 3703-3712. (link)

  • Plowright, R. K., Field, H. E., Smith, C., Divljan, A., Palmer, C., Tabor, G., Daszak, P. & Foley, J. E. (2008) Reproduction and nutritional stress are risk factors for Hendra virus infection in little red flying foxes (Pteropus scapulatus). Proceedings of the Royal Society B: Biological Sciences, 275(1636), 861-869. (link)