Viral gastroenteritis.

There are many viruses infecting the human gut: some are found to cause acute gastroenteritis regularly (although not always) like rotaviruses, enteric adenoviruses, small round structured viruses and astroviruses; others enter the host via the gut and most often cause systemic infection (entero-viruses, parvoviruses); and others are not regularly associated with human disease (reoviruses, viruses of the Coronaviridae family). The human gut can also be infected directly by HIV and, as a consequence of immuno-suppression, by viruses of the Herpesviridae family. Most remarkable during the last one to two years were the following results: increasing evidence that a tetravalent rhesus rotavirus-based vaccine can prevent severe disease after natural human rotavirus infection bringing this vaccine candidate close to approval by the Food and Drug Administration, USA; better, although not complete, understanding of correlates of protection from rotavirus infection; and fuller comprehension of the genomic and antigenic diversity of viruses of the Caliciviridae family infecting man. There is still no proficient tissue culture system for the human small round structured viruses, hindering the acquisition of basic knowledge of the replication of these viruses in the human gut. Except against rotaviruses, there are no vaccine candidates against human enteric viruses.