title: Increased norovirus activity was associated with a novel norovirus GII.17 variant in Beijing, China during winter 2014-2015.
abstract: BACKGROUND
  Norovirus (NoV) is a leading cause of sporadic cases and outbreaks of acute gastroenteritis (AGE). Increased NoV activity was observed in Beijing, China during winter 2014-2015; therefore, we examined the epidemiological patterns and genetic characteristics of NoV in the sporadic cases and outbreaks.
  
  
  METHODS
  The weekly number of infectious diarrhea cases reported by all hospitals in Beijing was analyzed through the China information system for disease control and prevention. Fecal specimens were collected from the outbreaks and outpatients with AGE, and GI and GII NoVs were detected using real time reverse transcription polymerase chain reaction. The partial capsid genes and RNA-dependent RNA polymerase (RdRp) genes of NoV were both amplified and sequenced, and genotyping and phylogenetic analyses were performed.
  
  
  RESULTS
  Between December 2014 and March 2015, the number of infectious diarrhea cases in Beijing (10,626 cases) increased by 35.6% over that of the previous year (7835 cases), and the detection rate of NoV (29.8%, 191/640) among outpatients with AGE was significantly higher than in the previous year (12.9%, 79/613) (χ(2) = 53.252, P < 0.001). Between November 2014 and March 2015, 35 outbreaks of AGE were reported in Beijing, and NoVs were detected in 33 outbreaks, all of which belonged to the GII genogroup. NoVs were sequenced and genotyped in 22 outbreaks, among which 20 were caused by a novel GII.17 strain. Among outpatients with AGE, this novel GII.17 strain was first detected in an outpatient in August 2014, and it replaced GII.4 Sydney_2012 as the predominant variant between December 2014 and March 2015. A phylogenetic analysis of the capsid genes and RdRp genes revealed that this novel GII.17 strain was distinct from previously identified GII variants, and it was recently designated as GII.P17_GII.17. This variant was further clustered into two sub-groups, named GII.17_2012 and GII.17_2014. During winter 2014-2015, GII.17_2014 caused the majority of AGE outbreaks in China and Japan.
  
  
  CONCLUSIONS
  During winter 2014-2015, a novel NoV GII.17 variant replaced the GII.4 variant Sydney 2012 as the predominant strain in Beijing, China and caused increased NoV activity.
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. zhiyonggao1@163.com.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. yy0728@sohu.com.
authors.forename: Baiwei
authors.initials: B
authors.lastname: Liu
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. howardhuo@139.com.
authors.forename: Da
authors.initials: D
authors.lastname: Huo
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. hqyan907@sina.com.
authors.forename: Hanqiu
authors.initials: H
authors.lastname: Yan
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. lailajia@126.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Jia
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. dyw1308@126.com.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Du
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. qiankun620@163.com.
authors.forename: Haikun
authors.initials: H
authors.lastname: Qian
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. yy_yy0707@qq.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. wangxiaoli198215@163.com.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. lijie304@sina.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, No.16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. bjcdcxm@126.com.
authors.forename: Quanyi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000068476:Beijing / Q000453:epidemiology; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D036022:Capsid Proteins / Q000235:genetics; D003967:Diarrhea / Q000453:epidemiology / Q000821:virology; D004196:Disease Outbreaks; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology*; D006761:Hospitals; D006801:Humans; D029322:Norovirus / Q000235:genetics* / Q000472:pathogenicity*; D010045:Outpatients; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D012621:Seasons
chemical_list: D036022:Capsid Proteins