Objective      To investigate the prevalence of norovirus-associated acute viral diarrhea in children from Chongqing in the year of 2014

and analyze the genotypes and recombination.       Methods       All norovirus-associated diarrhea samples were collected from children with acute viral diarrhea admitted in our hospital during the year of 2014. RT-PCR was used to amplify the capsid region of NV GⅠ and GⅡ. All the positive products were sequenced

and the obtained sequences were analyzed for genotyping and phylogenetic tree. To study the NV recombination

both RdRp and capsid regions of all the positive products were amplified

and the recombination was identified by SimPlot software.       Results      There were 511 specimens collected from 290 male and 221 female children

and 67 of them positive to NV GⅡ

with a positive rate of 13.1% (67/511). The NV epidemic peak was from August to October

and the peak age group was between 7 to 12 months old groups. Five genotypes based on capsid gene diversity were identified in 67 norovirus strains

including GⅡ.4 Sydney 2012 (42/67

62.7%)

GⅡ.3 (8/67

11.9%)

GⅡ.17 (8/67

11.9%)

GⅡ.6 (7/67

10.4%)

and GⅡ.14 (2/67

3.0%). Fifty-nine norovirus strains were sequenced successfully in the both RdRp and Capsid regions at the same time. Fifty-two specimens were recombination strains

and 4 recombination types of NV GⅡ were detected

including GⅡ.e/GⅡ.4 Sydney 2012 (42/52

80.8%)

GⅡ.12/GⅡ.3 (6/52

11.5%)

GⅡ.7/GⅡ.6 (2/52

3.8%)

and GⅡ.7/GⅡ.14 (2/52

3.8%).       Conclusion      The positive rate of NV is 13.1% in Chongqing region in the year of 2014

GⅡ.4 Sydney 2012 is the predominant strain

and NV recombination is very common.