CR2025_59 Interactions between chemical pollutants and an emerging infectious disease of wildlife

Lead Supervisor: Kevin Arbuckle, Department of Biosciences, Swansea University

Email: kevin.arbuckle@swansea.ac.uk

Co-supervisors: Joel Loveridge, Department of Chemistry, Swansea University; Steven Allain, Faculty of Science and Engineering, Anglia Ruskin University

Amid the global biodiversity crisis, the UK’s 2023 State of Nature report identified pollution as a major threat to British wildlife (Burns et al., 2023). However, biodiversity is increasingly being impacted my multiple threats simultaneously, which have the potential to exacerbate each other. For example, wildlife disease is a key emerging threat (Burns et al., 2023), and animals with exposure to pollutants could have weak immune systems (Minias, 2023). Pollution therefore has the potential to intensify the impact of emerging diseases through reducing reproductive success, increasing mortality and generating suboptimal changes in population demography. However, our understanding of how these two threats interact in the natural environment is severely limited.

Snake fungal disease (SFD), a lethal pathogen originating in North America, has been found in grass snakes (Natrix helvetica) from southeast England within the last decade, posing a new threat to British wildlife (Allain et al., 2024; Fig. 1). The external supervisor on this project (SA) completed his PhD project investigating SFD in grass snakes at a field site in Norfolk which has substantial variation across the site in proximity to sources of heavy metal and rodenticide pollutants (Allain, 2022).

Importantly, the grass snakes at the field site have been extensively characterised in terms of their population ecology and demographic characteristics, providing an exceptional level of background information for any field study of snakes. Hence, this study opportunity provides an excellent and tractable model to investigate how different environmental threats can interact in the field. In particular, this will enable us to test whether the dynamics of an emerging infectious disease and environmental pollution synergistically impact wild animals.

We will leverage this well-researched field site with abundant grass snakes (1164 snake captures over a three year period of a PhD; Allain, 2022), varying pollution levels (of both heavy metals and rodenticides), and SFD incidence (recently estimated as ~25%; Allain et al., 2024) to investigate how levels of pollutants in the snakes influences their susceptibility to SFD. We will also test whether these factors interact to influence mortality rates via recaptures over the course of the PhD and any demographic shifts (e.g. disproportionate loss of adults or juveniles) related to the intensity of each threat.

Specifically, the project will (1) quantify pollutant levels in field-collected scale clip samples from grass snakes using methods from analytical chemistry (ICP-OES for heavy metals and LC-MS for rodenticides), (2) map these threats across the site to identify hotspots and overlap, and (3) relate mortality to chemical pollutants, the presence of SFD and the interaction between them, controlling for sex, age, season, and location.

The interdisciplinary expertise within the supervisory team will provide a unique perspective and opportunity to investigate ecotoxicology within a behavioural and population ecology setting. This will provide novel insights into how pollution and emerging infectious diseases jointly influence wildlife health. Furthermore, this project will highlight the importance of taking a One Health approach to the study of emerging infectious diseases, which emphasizes the interconnectedness of human, animal, and environmental health (Rabinowitz et al., 2018).

Training opportunities: 

The interdisciplinary nature of this project will provide a multitude of opportunities for training and professional development of the student. They will learn analytical chemistry techniques (as mentioned in the project description) as well as field biology skills including sample collection, disease monitoring, and herpetological survey methods. The student will also benefit from strong connections between the supervisors and prominent organisations in UK reptile conservation (such as the British Herpetological Society and Amphibian and Reptile Conservation Trust), and therefore have abundant networking opportunities and encouragement for conference attendance and presentation of the research. 

Student profile:

This project would be suitable for students with a degree in chemistry, zoology (with some chemistry experience or keen interest in developing these skills), or a related environmental or biological science.

References:

• Allain, S.J.R. 2022. Population Dynamics, Disease and Other Drivers in a Wild Snake Population. PhD dissertation, University of Kent
• Allain, S.J.R., Leech, D.I., Hopkins, K., Seilern-Moy, K., Fernandez, J.R.-R., Griffiths, R.A., Lawson, B. 2024. Characterisation, prevalence and severity of skin lesions caused by ophidiomycosis in a population of wild snakes. Scientific Reports 14:5162
• Burns, F., Mordue, S., al Fulaij, N., Boersch-Supan, P.H., Boswell, J., Boyd, R.J., Bradfer-Lawrence, T., de Ornellas, P., de Palma, A., de Zylva, P., Dennis, E.B., Foster, S., Gilbert, G., Halliwell, L., Hawkins, K., Haysom, K.A., Holland, M.M., Hughes, J., Jackson, A.C., Mancini, F., Mathews, F., McQuatters-Gollop, A., Noble, D.G., O’Brien, D., Pescott, O.L., Purvis, A., Simkin, J., Smith, A., Stanbury, A.J., Villemot, J., Walker, K.J., Walton, P., Webb, T.J., Williams, J., Wilson, R., Gregory, R.D. 2023. State of Nature 2023. The State of Nature partnership, Available at: www.stateofnature.org.uk
• Minias, P. 2023. The effects of urban life on animal immunity: adaptations and constraints. Science of the Total Environment 895:165085
• Rabinowitz P.M., Pappaioanou M., Bardosh K.L., Conti, L. 2018. A planetary vision for one health. BMJ Global Health 3:e001137