Progress and prospects of infection, prevention and control of norovirus in oyster

Norovirus (NoV) is the main pathogen of non-bacterial acute gastroenteritis. Oysters are important carriers for the spread of NoV, which can enrich NoV from contaminated seawater and environment through filter feeding. People tend to eat raw or lightly cooked oysters, which may cause NoV infections. About half of the foodborne diseases associated with oysters are caused by NoV. Reverse transcription fluorescent quantitative PCR (RT-qPCR) is the main method for detecting NoV, but it cannot distinguish infectious from non-infectious viruses effectively. Since NoV cannot be cultured in vitro, RT-qPCR has limitations in assessing the effectiveness of inactivation methods for NoV. Porcine gastric mucin (PGM), propidium monoazide (PMA) and other nucleic acid intercalators combined with RT-qPCR have shown potential applications in the detection of infectious NoV. High hydrostatic pressure treatment is an effective method to reduce norovirus in shellfish, and the pressure of over 400 MPa can inactivate NoV significantly. In this paper, we review the enrichment of NoV in oyster, the detection methods to distinguish infectious NoV and the inactivation of high hydrostatic pressure technology on NoV in Pacific oysters (Crassostrea gigas), pleated oysters (Alectryonella plicatulas) and Kumamoto oysters (C. sikamea), so as to provide references for the establishment of effective NoV risk warning and non-thermal inactivation technology in the future.