Epidemiological research progress on norovirus

Norovirus is the leading cause of non-bacterial gastroenteritis worldwide. Approximately 18%(95%CI:17%-20%) of acute gastroenteritis is associated with norovirus. The rate of acute gastroenteritis attributable to norovirus in developing country is relatively low, which accounts for 12%(95%CI:9%-15%).Norovirus is highly pathogenic.It can be spread via human-to-human transmission, food, drink water, ambient environments, etc.The food-borne outbreaks of norovirus diseases accounts for about 14% of the total outbreaks thereof on a global scale.Norovirus diseases are usually acute, spreading fast and involving wide ranges.They often outbreak among densely-concentrated crowds in tourist ships, military camps, hospitals, schools, etc.Norovirus infection has caused great disease burden to mankind, especially for children and the elderly.The main genotype causing norovirus infection is GⅡ, of which the predominant one is GⅡ.4.Japanese researchers found that the genotype which caused the Japanese norovirus pandemic in Japan in winter of 2016 was a new mutant strain, GⅡ.P16-GⅡ.4_Sydney 2012. The American CaliciNet which monitors norovirus outbreaks showed that from September, 2016 to January, 2017, the rate of the norovirus outbreaks attributable to GⅡ.P16-GⅡ.4_Sydney 2012 accounted for 62% of the total outbreaks thereof. The establishment of a wide range of monitoring networks for the molecular typing of epidemic noroviruses plays a very important role in the studies of relevant vaccines, as well as in the control and prevention of large-scaled outbreaks and occurrence of related diseases.