Viruses Associated with Acute Diarrhoeal Disease

Gastroenteritis in humans can be caused by viruses, bacteria and parasites. The pathogenesis differs considerably, depending on the infectious agent. Clinical symptoms, however, are similar and range from mainly upper gastrointestinal symptoms including vomiting, to acute watery or bloody diarrhoea with and without vomiting, or combinations thereof. Viral gastroenteritis is a global problem in infants and young children. Viruses which are known to cause human gastroenteritis belong to genera of different virus families: rotaviruses (Reoviridae); enteric adenoviruses (Adenoviridae); small round structured viruses (SRSV's) and classic human caliciviruses (all Caliciviridae); astroviruses (Astroviridae). In terms of relative incidence frequency, rotaviruses account for approximately 70% of enteric adenoviruses, 12% of caliciviruses and astroviruses and of 8% each of all cases of viral gastroenteritides in children. Human immunodeficiency virus can infect the gut directly. Under conditions of immunosuppression the following viruses were also found to infect the gut and cause gut disease: Herpes simplex viruses (Herpesviridae); Cytomegalovirus (Herpesviridae); Picobirnaviruses (Birnaviridae). Many of the obligatory gastroenteritis viruses do not grow at all, or not very well, in tissue culture, and therefore virus isolation is not the diagnostic method of choice. By contrast, electron microscopy permits the differentiation of viruses on the basis of their characteristic morphology.