Project highlights

  • Investigating the ecological (climate, landscape) drivers of zoonotic disease in wild rodents
  • Integrating field surveys with large-scale agricultural trails of rice farming practices.
  • Multidisciplinary training integrating disease ecology at University of Warwick with global change perspectives at the International Rice Research Institute.

Overview

Land-use changes due to intensified agricultural practices are a concern in the Philippines (Dirzo et al, 2014). The replacement of forests by mixed agroecosystems and high-value crops has led to biodiversity loss and increased contact of humans with wild animal populations. Consequently, changes in the ecology of wild animals have led to changes in the epidemiology of diseases and emergence of novel livestock and human pathogens, e.g. zoonotic diseases (Olival et al, 2017).

In the Philippines, 4.7 million hectares of land are dedicated to rice farming alone (PhilRice, 2020). Rice is a vital dietary component in the Philippines that provides an estimated 109-kilogram of food per-capita each year. However, the rise of rice production has also provided generalist rodent species increased availability of food sources (Singleton et al, 2008). Due to their role as disease vectors, increases in their abundance and anthropogenically driven shifts in their distribution pose a significant threat to the public health (Baker, 2007). A study investigating the effect of land cover data on rodent pathogen prevalence identified a positive association between synanthropic rodent abundance and increased habitat fragmentation and agricultural land cover (Morand et al, 2019). The study also revealed an association between these human-altered landscapes and the presence of zoonotic pathogens. While it is known that human-altered landscapes, particularly agroecosystems influence the transmission of infectious diseases in general, a mechanistic understanding of how changes from agricultural practices influence disease risk is needed. This information could inform current surveillance efforts as well contribute to a broader understanding of disease spill-over.

Therefore, this project will investigate the transmission ecology of rodent borne disease in agroecosystems. It will apply an interdisciplinary and systems approach to uncover key mechanisms influencing pathogen dynamics within the rodent vectors as well as the pathways / barriers to disease spill-over from rodents to humans or livestock.

Host

University of Warwick

Theme

  • Climate and Environmental Sustainability
  • Organisms and Ecosystems

Supervisors

Project investigator

Co-investigators

How to apply

Methodology

Specifically, the study aims to:

  1. Identify how agricultural practices and the environment (weather and landscape) influence of rodent population growth and their spatial distribution.
  2. Evaluate the effects of rodent population dynamics on pathogen prevalence?
  3. Identify the knowledge, attitude, and practice (KAP) of rice farmers that contribute to their exposure to rodent-borne zoonoses; and
  4. Create a predictive risk map of disease incidence and intensity for rodents and rice farmers based on the evaluated risk factors.

We will align rodent sampling and disease testing with ongoing field trials run by IRRI.  Sampling will quantify rodent abundance, species composition, demography (age, sex), and multiple measures of animal health (body condition, size, fecundity ect.). Because zoonotic disease risk is influenced by both ecological and social factors, our risk maps (aim 4) will integrate data on rodent disease (aim 1& 2) with a data collected using a household survey of rice farmers (aim 3).

Training and skills

The interdisciplinary nature of this project results in different training form project partners. At Warwick, the student will join a large group of disease ecology and epidemiology researchers. This will provide training in the collection and analysis of disease data. In the Philippines, IRRI will provide expertise global change biology and rice farming.  The candidate has experience with rodent sampling and monitoring in the Philippines.

Partners and collaboration

This project is a collaboration between the University of Warwick and IRRI.  Erin Gorsich is a disease ecologist at the University of Warwick specialising in the ecological and evolutionary drivers of disease (https://warwick.ac.uk/fac/sci/lifesci/people/egorsich/).

The International Rice Research Institute is dedicated to abolishing poverty and hunger among population that depend on rice-based agri-food systems (https://www.irri.org/).  They work to address multiple sustainable development goals, including climate action (SDG 13), responsible consumption and production (SDG 12), life on land (SDG 15), among others focused on poverty and hunger.

Further details

If you would like to apply to the project please visit: https://warwick.ac.uk/fac/sci/lifesci/study/pgr/studentships/nerccenta/

Possible timeline

Year 1

Analyse previous data collected to relate agricultural practices, environmental conditions, and rodent population dynamics.  Develop methods for disease sampling.

Year 2

Building on methods developed in Year 1, collect disease and conduct household surveys.

Year 3

Quantify and map relationships among agricultural, rodent, disease, and household datasets.

Further reading

Baker, D.G. (2007). Flynn’s parasites of laboratory animals (2nd edition). Blackwell.

Dirzo, R.H.S., Young, M., Galetti, G., Ceballos, N., Isaac, J., & Collen, B. (2014). Defaunation in the Anthropocene. Science 345:401–416.

Morand, S., Blasdell, K., Bordes, F., Buchy P., Carcy, B., Chaisiri, K., Chaval, Y., Claude, J., Cosson, J., & Desquesnes, M. (2019). Changing landscapes of Southeast Asia and rodent-borne diseases: decreased diversity but increased transmission risks. Ecological Applications DOI: 10.1002/eap.1886.hal-02105014.

Olival, K.J., Hosseini, P.R., Zambrana-Torrelio, C., Ross, N., Bogich, T.L., & Daszak, P. (2017). Host and viral traits predict zoonotic spill-over from mammals. Nature 546:646–650.

Philippine Rice Research Institute. (n.d.). Rice Statistics – PalayStat System (2021): Estimated production, area harvested and yield per hectare (PAY). Retrieved September 4, 2021, from https://palaystat.philrice.gov.ph/statistics/retrieve/table/1

Singleton, G.R., Joshi, R.C., & Sebastian, L.S. (2008). Philippine Rats: Ecology and Management. Philippine Rice Research Institute: Science City of Muñoz, Nueva Ecija.

 

COVID-19

We do not envision any significant impact of the COVID-19 pandemic to project delivery, given that the work will be conducted in collaboration with IRRI.  Even during a hard lockdown, previous data is available for analysis to address aim 1, and there is sufficient work for a PhD if aim 3 cannot be completed.