ABSTRACT
Norovirus is a major cause of viral gastroenteritis outbreaks worldwide causing up to 200#000 deaths in the developing world. In developed countries, infection is seasonal – “winter vomiting disease”. New variants of norovirus genotypes regularly appear causing an increased number of outbreaks throughout the year. Spread is via the fecal-oral route. The main source is another infected person, contaminated food, or water. Immunity is short-lived and re-infection common. Very little is known regarding the pathogenesis of norovirus infection. Intestinal enterocytes appear to be the primary site of viral infection, but viral antigen has been detected in macrophages, dendritic and T cells in the lamina propria. The clinical presentation is self-limiting vomiting and diarrhea. The main complication is dehydration and there may be persistent diarrhea in the immunocompromised. Diagnosis relies on reverse transcription PCR to detect viral nucleic acid in vomit or feces. There is no specific treatment or vaccine. Control of outbreaks includes reinforcing good hygiene, closure of hospital wards and isolation of ill persons until 48 hours after symptoms have resolved.
