The Molecular Virology of Enteric Viruses

Foodborne and waterborne viruses cause a range of illnesses, from acute gastroenteritis (caliciviruses –noroviruses and sapoviruses-, rotaviruses, astroviruses, and enteric adenoviruses), to hepatitis (hepatitis A virus and hepatitis E virus), and other diseases. Recently, next-generation sequencing technologies have allowed the discovery of new enteric viruses (novel astroviruses, kobuviruses, saliviruses, etc.). Noroviruses are the leading cause of acute gastroenteritis outbreaks and sporadic cases in children and adults worldwide and they still remain refractory to routine cell culture propagation. Recent studies have shown that histo-blood group antigens (HBGAs) are cellular carbohydrates that serve as receptors and host susceptibility factors for human noroviruses. They evolve based on antigenic changes and differential glycan binding specificities. In the last years there have been significant advances in the knowledge of their replication mechanisms, pathogenicity and genetic evolution. The strain diversity and the evolution of rotaviruses are also a matter of concern, despite the introduction of rotavirus vaccines. Similarly, molecular analyses of orally transmitted viruses causing hepatitis are clarifying the phylogenetic relationships between these viruses and other viral genera, as well as their pathophysiological mechanisms.