Epidemiologic and genetic characteristics of norovirus caused acute gastroenteritis in Huzhou,Zhejiang,2016

Objective To understand the epidemiologic and genetic characteristics of norovirus caused acute gastroenteritis in Huzhou,Zhejiang province,in 2016. Methods From January to December 2016,a total of 501 stool samples were collected from acute gastroenteritis cases in sentinel hospitals for active surveillance of food-borne diseases in Huzhou. Realtime RT-PCR was performed to detect the nucleic acid of norovirus. The amplification and sequencing of partial VP1 regions were performed with RT-PCR. The genotyping of norovirus was confirmed by phylogenetic analysis and online typing tools. Results Of the 501 stool samples from acute gastroenteritis cases,101 were positive for norovirus(20.16%). Genogroup G Ⅱ was predominant(86.14%). The detection rates in men and women were 20.75%(50/241)and 19.54%(51/260) respectively,the difference was not significant. Norovirus positive cases were found in all age groups,but the positive rate was highest in children aged 5 years. Norovirus infection occurred all the year round,but the infection rate was low during June-September. The norovirus genotypes detected in 2016 were diverse,including GⅡ.17,GⅡ.4 Sydney-2012,GⅡ.3, G Ⅱ.13,G Ⅰ.6,G Ⅱ.2,G Ⅱ.6,and G Ⅰ.7,but G Ⅱ.17and G Ⅱ. 4 Sydney 2012 were predominated alternatively by months. Conclusion The genotypes of norovirus detected in acute gastroenteritis cases in Huzhou were diverse,and the predominant genotype varied with month. It is necessary to strengthen the surveillance for the local infection status and genotype distribution of noroviruses.