32 – Gastroenteritis viruses

: Viruses causing gastroenteritis (GE) are among the most common causes of foodborne illness worldwide, with the noroviruses (NoV) ranking number one in many industrialized countries. The gastroenteritis viruses belong to several virus families and include NoVs and sapoviruses (family Caliciviridae), kobuvirus (Aichivirus, family: Picornaviridae) (Yamashita et al., 1998), rotavirus (family: Reoviridae), adenoviruses (family: Adenoviridae) and astrovirus (family: Astroviridae). Gastroenteritis viruses are transmitted by the faecal-oral route; they are shed in vomitus and faeces and enter their next victim orally. In persons with clinical illness, GE viruses typically are detected in stools at levels far exceeding 106 virus particles/ml. Even though the average attack rate of the GE viruses is high (exceeding 45 %), asymptomatic infections do occur and these individuals do excrete virus. Due to the lack of an envelope, these GE viruses are very stable and can remain infectious in the environment, in water or on foods for prolonged periods. Therefore, foods can be contaminated anywhere along the food chain: from farm to fork. High risk commodities are fresh produce, catered sandwiches and salads, and bivalve filterfeeding shellfish. Prevention of gastroenteritis virus infection including foodborne transmission will rely on high standards for personal and environmental hygiene. The goal should be to prevent contamination of food items rather than to rely on treatment processes to inactivate the viruses once present in the foods or water. In daily practice this means that awareness among food-handlers, including seasonal workers, about the transmission of enteric viruses is needed (including the spread of viruses by vomiting), with special emphasis on the risk of transmission by asymptomatically infected persons and those continuing to shed virus following recovery from illness.