Shellfish, drinking water and vegetables are known vectors of enteric viruses as they are prone to sewage contamination. Sewage contain all enteric viruses that circulate in the population and a study in different treatment plants in Norway showed high le vels of several enteric viruses in treated sewage as well. Hepatitis A virus was also found in a treated sample. However, molecular detection was used and this method does not reflect the infectious status of the viruses.
1. This project includes a study on sewage with assays for the detection of infectious viruses. A Caco-2 and a BGMK cell culture combined with TaqMan PCRs will be established to detect astro-, rota-, enteric adeno- and enteroviruses, which propagate in these cell lines. These integrated cell culture PCRs will be used to assess the distribution of infective enteric viruses in sewage and to study their removal in different treatment systems. Noro- and hepatitis A virus are not culturable and will be quantitated by real time PCRs.
Due to cumbersome procedures and the presence of PCR inhibitors, an internal control will be developed to prevent false negatives and to facilitate relative quantitation of viruses.
2. Shellfish are filter-feeders and accumulate enteric viruses from their water environment. Noro- and enteric adenoviruses have been detected in Norwegian mussels. The detection method is, however, cumbersome and a simplified standardised method will be established to facilitate screening of shellfish for viral quality.
3. Bacteria l pathogens have been internalized into lettuce grown in contaminated soil. To test for the possibility that enteric viruses may be internalized into the root systems of vegetables, lettuce will be grown in soil contaminated with norovirus.
4. As noroviru s can not be grown, viral inactivation studies must be performed on model viruses. The cultivation of a bovine and a mink enteric calicivirus will be attempted in several cell lines under different conditions.