Abstract:Objective To study the pollution condition of Vibrio parahaemolyticus and Norovirus in some of bivalve mollusks sold in the market in Shunyi District and provide evidence for the prevention and treatment of infectious diarrhea. Methods The bivalve molluscs in the market of Shunyi District were collected from July to October of 2017. The appropriate samples were taken to separate the digestive glands, and virus RNA was extracted and real-time fluorescence quantitative reverse transcription-polymerase chain reaction(RT-PCR)was used to detect Noroviruses. The Vibrio parahaemolyticus was examined in the remaining samples following the national food safety standard GB 4789.7-2013.The genetic testing of virulence gene, drug resistance analysis and pulse field gel electrophoresis (PFGE) test were carried out on the isolated Vibrio parahaemolyticus. Results A total of 18 strains of Vibrio parahaemolyticus were detected among 50 samples of shellfish with the positive rate of 36.0%. Eight samples contained Norovirus. The virulence genetype of one isolate was tlh-tdh-trh- and the others were tlh+tdh-trh-. All isolates were resistant to ampicillin and sensitive to some other antibiotics. The PFGE patterns of different strains were polymorphic and belong to different clones. Norovirus was detected only in October and distributed in oysters, scorpions, and scallops, which are GⅡ-type nucleic acid positive. Conclusion The Vibrio parahaemolyticus and Norovirus of GⅡ were present in commercially available bivalve molluscs in Shunyi District. The isolated Vibrio parahaemolyticus was polymorphic, but the virulence genes had a low rate and were sensitive to most antibiotics.