Objective: To acknowledge the epidemiology of gastroenteritis outbreaks caused by noroviruses and their genotypes.
Methods: Epidemiologic data and specimens were collected from 19 gastroenteritis outbreaks. 201 specimens were detected for norovirus, rotavirus, astrovirus, adenovirus and sapovirus by RT-PCR methods and PCR products were sequenced. Sequence alignment and phylogenetic analysis were performed by Clustal X 1.83 and MEGA 4.0 programs.
Results: Noroviruses were one of the most predominant pathogens causing viral gastroenteritis outbreaks (12 of 19 outbreaks, accounting for 63.2%). Variant GII-4/2006b was the predominant strain responsible for 11 of the 12 NV-associated outbreaks. Other genotypes would include GII-17, GII-6 and GII-3. The NV-associated gastroenteritis outbreaks occurred mainly in winter and spring between December 2006 and April 2007. These gastroenteritis outbreaks caused by noroviruses would involve all age groups in various locations. Meantime, 2 out of 12 outbreaks were caused by norovirus or other viruses. In addition, multiple viruses and multiple genotypes of noroviruses were found in the same outbreak.
Conclusion: Noroviruses were one of the most major pathogens causing gastroenteritis outbreaks while GII-4/2006b variant was identified as the predominant strain in China.