|Food- and waterborne transmission play an important role in the spread of norovirus (NV, previously named Norwalk-like viruses) throughout Europe. NV are ubiquitous, highly contagious, and cause large international outbreaks of gastro-enteritis. This is of concern: current quality control for food and water in Europe measures bacterial contamination, and does not monitor viral contamination. Therefore, food can pass microbiological quality control, but still contain viruses. Matched with the virtual absence of a surveillance system for detection of common-source outbreaks of illness due to enteric viruses, this highlights a weak spot in European infectious disease control. The NV in fact serve as sentinels: when present, common-source outbreaks will relatively easily be detected due to the high attack rate and short incubation period. More insidious, however, are the enteroviruses and faecally-transmitted hepatitis viruses with a high proportion of asymptomatic infection after an incubation period of up to 2 months. These viruses cause illnesses like hepatitis (hepatitis A and E viruses) and infections of the central nervous system (enteroviruses). Signalling common source outbreaks with these viruses is virtually impossible without a strong (molecular) laboratory component to underpin the epidemiological investigations, aided by international exchange of laboratory data. The work in this proposal aims at providing the laboratory tools needed for successful (epidemiological) surveillance networks on food-borne outbreaks, hepatitis A viruses, and rare and emerging diseases (attributable to enteric viruses) that are being developed under DG Sanco's Communicable Disease Surveillance Network. We build on information gathered through a previously funded (FP5) research network, in collaboration with coordinators of surveillance networks in DG Sanco, to help put the research findings into practical use for the above mentioned activities.