Fisheries and Aquaculture
New tools to forecast and prevent norovirus contamination of farmed oysters
GEN009- Project Leaders: Timothy Green, Nico Prins
- Institutions: Vancouver Island University (VIU)
- Budget: $312470
- Program/Competition: GeneSolve
- Genome Centre(s): Genome British Columbia
- Fiscal Year: 2019
- Status: Closed
Gastroenteritis from contaminated oysters and other shellfish is a major public health issue in BC, leading to closures of shellfish harvesting areas, significant economic losses for shellfish farmers and damaging BC’s reputation as a high-quality-seafood producer. Pollution from human sewage can contaminate oysters and other filter feeders, highlighting the need to identify sewage sources and to understand the spread and persistence of microbial pathogens.
This project focused on norovirus due to recent outbreaks linked to raw BC oysters. Noroviruses that make people sick are not naturally found in marine environments so they must originate from a human source.
Researchers from the Vancouver Island University (VIU) and partners from the BC Shellfish Growers Association (BCSGA) and the BC Ministry of Agriculture and Food (BC MAF) came together to provide BC oyster farmers with the knowledge to predict and mitigate costly outbreaks of norovirus.
To track norovirus in the main oyster-growing area of BC, Baynes Sound, the team developed a rapid norovirus sequencing test to identify different types of human norovirus as they spread through the Baynes Sound area. They used this test to check over 6,800 oysters from 12 different sites over two winters.
Data from this study suggests that norovirus can disperse up to 15 km and can live for up to 28 days in coastal waters. When the researchers compared where the norovirus was found in oysters to Google Earth maps showing sewage plumes it showed that small boat harbors and urban settings are a big risk for shellfish farms in the area. Repeated testing at another farming area within Baynes Sounds during a third winter season confirmed these findings.
A short-term solution for the shellfish industry could be to clean harvested oysters by storing them in clean water during the usual winter norovirus season. However, the results from this project strongly suggest the real long-term solution is to improve wastewater infrastructure and promote responsible sewage disposal by boaters.
