01 Dec 11 Norovirus stability in food manufacturing and the environment
Human noroviruses are the single biggest cause of gastroenteritis in the industrialised world and are associated with foodborne disease and rapid person to person transmission. New research has shed new light on the behaviour of these pathogens.
Unfortunately, unlike other viruses, human noroviruses cannot be grown in the laboratory so scientists have struggled to understand how best to inactivate them.
New research carried out by Leatherhead Food Research and co-funded by the Department for Environment Food and Rural Affairs and a consortium of industrial companies and the Health Protection Agency, through the Food Quality and Innovation LINK programme, has forged new understanding on the behaviour of these pathogens.
The scientific team led by Dr Angus Knight firstly developed and tested a new molecular method for measuring virus inactivation (without the need to grow virus) using a distantly related cat vaccine virus that is safe to use and can be grown in the laboratory. The team then applied the same molecular approach to human noroviruses in order to predict their behaviour.
Surprisingly the noroviruses were much more resistant to temperature and a range of disinfectants and hand sanitisers compared with other viruses. Interestingly, when the cat vaccine virus was added to human norovirus samples, the cat virus became much more resistant and behaved more similarly to the human noroviruses.
The findings suggest that the increased resistance of the human noroviruses is derived from their natural human faecal environment. This increased resistance may explain why these organisms persist in the environment and are difficult to control leading to prolonged outbreaks of disease. Further work is now required to develop more effective hygiene control measures for human norovirus.
- Topping, J.R., Scherer, H., Haines, J., Scott, M., Carter, M.J., Wilcock, M.M., Bellamy, K., Brown, D.W., Gary, J.J., Gallimore, C.I. , Knight, A.I. (2009) Temperature inactivation of Feline Calicivirus vaccine strain FCV F-9 in comparison with human noroviruses using an RNA exposure assay and Reverse Transcribed Quantitative Real-Time Polymerase Chain Reaction – a novel method for predicting virus infectivity. Journal of Virological Methods, 156, 89-95.
- Nowak, P., Topping, J.R., Gallimore, C.I., Gray, J.J. Iturriza-Gómara, M., Knight, A.I. (2011) Measurement of the virolysis of human GII.4 norovirus in response to disinfectants and sanitisers. Journal of Virological Methods, 174: 7-11.
- Nowak, P., Topping, J.R., Bellamy, K., Fotheringham, V., Gray, J.J., Golding, J., Wiseman, G., Knight, A.I. (2011) Virolysis of feline calicivirus and human GII.4 norovirus following chlorine exposure under standardised light soil disinfection conditions. Journal of Food Protection (in press).