QUADRAT DTP: Unravelling the evolutionary and ecological drivers of parasite virulence to mitigate proliferative kidney disease emergence and spread

Climate change is projected to cause elevated water temperatures with far-reaching effects on nutrient cycling, population ecology and shifts in species distributions. A crucial consequence of increasing water temperatures is the potential for severe disease outbreaks among aquatic animal populations. Aquatic pathogens are likely to exhibit strong shifts in phenological, behavioural and life-history phenotypes in response to environmental change. However, the effects of enhanced transmission and virulence on host ecology, adaptation and evolution are poorly understood. 

Proliferative kidney disease (PKD), a devastating disease of salmonid fish in the UK, Europe, and USA, is caused by the myxozoan parasite, Tetracapsuloides bryosalmonae. In Europe and in the USA, major outbreaks have also occurred in non-salmonids with  mass die-off events being recorded in whitefish populations in the USA. T. bryosalmonae is also widespread in UK wild salmonid populations and may become a more serious issue in the future as climate change processes continue to evolve.  

A major barrier in tackling PKD is the lack of understanding of parasite virulence and links with climate-driven processes such as increased water temperatures. Intrinsically Disordered Proteins (IDPs) are virulence factors important in infectious disease, including COVID-19. Microexon genes (MEGs) encode IDPs thought to be unique to helminth parasites. The Aberdeen team have uncovered a novel T. bryosalmonae (Tb)MEG that acts as an important virulence factor. TbMEG-1 exhibits extensive sequence diversity in fish, which is likely to be linked to distinct parasite strains and virulence levels. However, the population-level diversity and concomitant capacity for immunogenomic adaptation in fish hosts is poorly understood. 

This project aims to investigate relationships between environmental factors, pathogen virulence and adaptive diversity with a focus on TbMEG-1 and other parasite IDPs implicated in immune evasion within fish hosts. The project will focus on fish populations in Yellowstone and Columbia River systems in the USA and in the Test, Itchen, and Avon rivers in the UK where PKD has increasing economic and ecological importance.  

Key questions are: 

• What are the levels of TbMEG-1 / IDP diversity in natural and farmed fish populations? 
• Are patterns of immunodiversity linked to parasite strains and/or virulence? 
• Are these links affected by environmental factors such as temperature change? 

The successful student will: 

• Use bioinformatics to shortlist secretory IDPs from the T. bryosalmonae genome. 
• Undertake targeted RNA-Seq to determine IDP profiles linked to distinct parasite strains and virulence levels. 
• Determine how these links are affected by ecological and environmental factors 
• Further develop serologic diagnostics to aid disease risk management 

The student may have the opportunity to undertake a 15-week lab and fieldwork study visit to the Yellowstone and Columbia rivers in 2023, where training will be provided in sample and data collection, including molecular and histological diagnostics, parasite genotyping, eDNA monitoring, electrofishing, and mark-recapture experiments. Fieldwork experience will also be gained at UK sites endemic for PKD. Aberdeen training will involve molecular techniques, including q-PCR, histology, and indirect ELISA, as well as  advanced bioinformatics and multivariate statistics. Other training opportunities will be available via Quadrat in communication, written, and presentational skills at project meetings and conferences. 

Candidate Background: Candidates should have or expect to achieve, a degree in biological sciences such as environmental science, ecology or molecular biology. The following experience is desirable, but not essential; experience in molecular biological techniques, statistical analyses (using R or equivalent), field work studies, and bioinformatics (including Linux OS and RNA-Seq analysis pipelines).

More project details are available here: https://www.quadrat.ac.uk/quadrat-projects/

How to apply: https://www.quadrat.ac.uk/how-to-apply/