Chapter 23 : Foodborne Viral Pathogens

Abstract:

Human enteric viruses are responsible for substantial morbidity worldwide. Transmitted predominantly by the fecal-oral route and exclusively in association with human feces and/or vomitus, these viruses come into contact with humans by a variety of routes, including the consumption of contaminated foods. From an epidemiologic perspective, the most significant of these are human noroviruses, which are the most common cause of acute gastroenteritis worldwide and are now recognized as the leading causes of foodborne illness. Enteric viruses can be transmitted directly by person-to-person contact or indirectly by consumption of contaminated food or water or contact with fomites. The usual source of enteric virus contamination is human fecal matter, which can easily harbor up to 1010 genomic RNA copies per gram when shed by infected individuals. Human enteric viruses have properties that are distinct from those of bacterial foodborne pathogens. Viruses are usually species specific and tissue tropic, meaning that the human enteric viruses are believed to infect only humans. Since they must resist the enzymatic conditions and pH extremes encountered in the gastrointestinal tract, enteric viruses are also resistant to a wide range of commonly used food-processing, preservation, and storage treatments.