Norovirus is a leading cause of viral gastroenteritis worldwide. People can catch norovirus in different ways, for example, by eating contaminated food like shellfish collected from polluted waters. In New Zealand, several norovirus outbreaks have been linked to locally produced and imported shellfish. These outbreaks don’t just affect people’s health, they also harm the food industry by raising costs for producers, creating trade issues and triggering stricter regulations.
A significant challenge is we don’t know much about how much norovirus exposure is required to cause illness. Some studies suggest that the higher the amount of norovirus present, the greater the risk, but even very small amounts can still cause illness.
To better understand and manage this risk, PHF Science developed a new test capable of detecting very small amounts of norovirus in shellfish. When applied to samples from past outbreaks, the test showed even trace amounts of the virus can make people sick, underscoring how hard it is to set a clear “safe” limit.
This research provides valuable evidence for assessing the risks of contaminated shellfish and for reviewing food safety guidelines.
The study was funded by the Ministry for Business, Innovation and Employment (MBIE) through the Cawthron Institute, with additional support from the Ministry of Health.
You can learn more about this research in the open-access article Droplet Digital PCR for Precise Quantification of Human Norovirus in Shellfish Associated with Gastroenteritis Illness published in the Journal of Food Protection.