Abstract: 【Abstract】:Object: To understand the status of Novorirus infection in infants and children in Tianjin area , and study the genotype and the genetic identity of Norovirus . Methods : The fecal specimens from infants and young children with viral gastroenteritis were collected from Tianjin Children hospital from August 2008 to July 2009 .The viral RNA was amplified by a reverse transcription polymerase chain reaction (RT-PCR). The amplied genes were the sequenced and compared with the Norovirus sequences deposited in GeneBank. By DNAstar and Bioedit software to evaluate sequence homology and generated the phylogenetic tree .Results: NV was detectable in 174 cases out of the 540 specimens. The positive rate was 32.22% .Nucleotide sequence analysis showed that the NrV strains all belonged to GⅡ-4 . The sequences of specimens were closer to the viral sequence obtained from Beijing . Conclusion: NV is one of the important diarrhea pathogens of viral gastroenteritis in infants and young children in Tianjin area and the GⅡ-4 is the major prevalent strain.

Key words: norovirus, genogroup, RT-PCR, diarrhea