Norovirus detection and genotyping for children with acute diarrhea in autumn and winter in Shenzhen

Abstract

Objective To investigate the infection situation of Norovirus and its genotype among children with acute diarrhea in autumn and winter in Shenzhen.Methods Fecal specimens were collected from 307 children under 5 years of age with acute diarrhea from September 2009 to January 2010 in Shenzhen.Reverse transcription polymerase chain reaction (RT-PCR) was used to detect nucleic acids of Norovirus.Amplicons obtained from some Norovirus positive stools were purified and sequenced.Phylogenetic analysis and genotyping were performed combined with the corresponding nucleotide sequence of GenBank reference strains.The recombinant Norovirus was analyzed and identified by SimPlot3.5.1.Results 38 out of 307 specimens were positive for Norovirus by RT-PCR with the positive rate of 12.4％.Norovirus was detected more frequently in children between 6 months to 2 years of age which corresponded to 81.6 ％ (31 /38) of all cases,with peak occurring in October and November which corresponded to 73.7％ (28/38) of all cases.25 out of 26 sequenced strains were GⅡ.4 2006b variant,and one strain was GⅡ.12/ GⅡ.3 recombinant genotype.Conclusion Norovirus is important pathogen for children with acute diarrhea in autumn and winter in Shenzhen.GⅡ.4 2006b variant is the predominant genotype in the population studied and recombinant strain.The genotype of first detected in Shenzhen is GⅡ.12/GⅡ.3. Key words: Norovirus; Diarrhea; Child, preschool; Genotype; Recombination, genetic