DERIVE - Detection and RIsk management of Verotoxigenic E. coli (VTEC) in the water Environment

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Fully funded DERIVE PhD Studentship in Environment and Health

- click the link above for project description and application details!
Closing date June 24th 2022.

‌One fifth of the Irish population get their drinking water from a private supply, which are susceptible to contamination with the zoonotic pathogen verotoxigenic E. coli (VTEC). Due to high rainfall, often unfavourable geology and high livestock density, Ireland has the highest incidence of VTEC infection in Europe, typically 10 times the EU average. Exposure to water from a private supply is the top risk factor for VTEC enteritis (41% cases), a serious illness that frequently requires hospitalisation, and in up to 10% of cases results in life-threatening haemolytic uremic syndrome (HUS).

The new Drinking Water Directive calls for a complete risk-based approach to water safety that assesses and manages the main risks in the catchment area and takes into account the impact of climate change. DERIVE will answer this call by developing a novel suite of complementary VTEC detection and risk assessment tools that can be applied at national level in catchments for the monitoring and risk-based management of VTEC.

Using previously generated data, we will identify two nationally representative catchments with high incidence of human VTEC infection and then carry out field studies to collect quantitative VTEC occurrence data in surface, ground and private drinking water for use in predictive modelling. For this purpose, a previously developed quantitative real-time PCR method will be optimised to detect VTEC in water, by combining it with a pre-validated filtration/amplification method. The resulting data will be combined with meteorological, hydrogeological, hydrodynamic and risk factor data, to develop an Environmental Fate Model and Hydrodynamic Catchment Model for each catchment.

These models will be statistically/mathematically paired to work in series, resulting in a risk assessment tool for predicting the hydrodynamic conditions leading to VTEC contamination from source to receptor. The tool will be validated using geo-referenced human VTEC infection data, and subsequently up-scaled to forecast drinking water contamination and VTEC infection under different climatic and
hydrogeological scenarios at the National level. In combination with pathogen loading, consumption rates and population data, it will enable dynamic Quantitative Microbial Risk Assessment (QMRA).

The risk assessment tools will be complemented by development and validation of a rapid molecular test for VTEC detection in drinking water, suitable for use on-site with minimal equipment and expertise. This test will detect VTEC toxin and E. coli specific genes, and will prove useful in the overall risk-based approach to supply protection and in environmental case/outbreak investigations, providing a rapid indication of supply contamination. Finally, a subset of the VTEC-positive water samples collected will be characterised via metagenomics analysis and compared to pre-existing data from human and animal associated VTEC to increase our understanding of the One Health epidemiology of VTEC in Ireland. This will enable source attribution of waterborne VTEC, and improved knowledge of their impact on human health.

Overall, the project will have major societal impact, involving key stakeholders and citizens and informing the design of preventative measures and risk mitigation strategies that can be applied at catchment level to protect private drinking water supply owners and better manage outbreaks.