The original VIRAQUA I project was focusing on exploring viral dynamics in the Conwy River and estuary. This was then expanded to other rivers and estuaries in Wales and England (VIRAQUA II). VIRAQUA III became the national COVID-19 surveillance programme. In order to investigate the fate and behaviour of enteric viruses, the goals of the fieldwork are:
1. To evaluate techniques for virus recovery from environmental samples.
Representative wastewater, freshwater, marine water and sediment samples are collected at wastewater treatment plants, river sites, estuaries, and coastal locations. These samples are being used in laboratory spiking experiments, where known concentrations of target viruses (e.g. SARS-CoV-2, Phi 6, Norovirus, Adenovirus, CrAssphage) are added. Using the spiked water and sediment samples the efficacy of different methods for the recovery of viruses from environmental matrixes can be evaluated. This has led to the development of standard protocols.
2. To estimate the impact of wastewater treatment plants on viral loads and their movements.
We have been studying the rate of decay of viruses and pathogenic bacteria as wastewater passes through the sewage network to the treatment plant and then its decay during wastewater treatments. This uses both RT-qPCR and infectivity assays to estimate the viability of viruses and their rate of discharge to the wider environment. Most recently, this work has involved tracing the fate of SARS-CoV-2 and different variants.
3. To explore viral movements, focusing on their potential to reach shellfish beds, recreational waters and beaches.
Regular sampling of surface water, wastewater, sediment and shellfish is being undertaken in rivers, estuaries and the major wastewater treatment plants in England and Wales. Viral concentrations in the collected samples are then determined by RT-qPCR and dd-PCR. These samples are also subjected to viral metagenomics and infectivity studies. Regular sampling will allow us to discover the seasonal and spatial viral dynamics and results will be used for modelling viral transport and creating risk maps for improved risk assessment. It will also allow us to measure disease incidence at the community level.
4. Evaluation of the usefulness of in situ samplers to explore temporal viral dynamics.
At sampling sites where the target viruses are present the following samplers will be deployed:
- Conventional automated sample collection system usually used for the nutrients and coliform bacteria investigations.
- Passive samplers traditionally used to evaluate chemical contamination.
- Novel passive samplers using media suitable for the enrichment of viruses.
The most useful approach then will be used to study temporal changes e.g. diurnal discharge patterns from wastewater treatment plants and during tidal cycles.