NoV Stool Samples, Oyster Samples and Anti-NoV mAb

NoV-positive stool samples used in this study were collected from The Third Affiliated Hospital of Sun Yat-sen University in our previous works and stored at −80°C in our laboratory (Xue et al., 2013, 2016, 2019). In brief, the stools samples were diluted using diethyl pyrocarbonate (DEPC)-treated phosphate buffered saline (PBS) solution to 10–20% (m/v), and then centrifuged at 7,000 × g for 5 min. The supernatant was stored as the viral stock at −80°C. The sample was identified as GII.4 by one-step RT-PCR and sequencing (Xue et al., 2013, 2016, 2019). Before use, the virus supernatant was taken out to extract total RNA, and the titer was determined by RT-qPCR as 6.24 × 10⁵ copies/μL. The appropriate titers used in this study were obtained by dilution with DEPC-treated PBS (Zhang et al., 2020). Oysters were obtained from Huangsha Aquatic Product Trading Market in Guangzhou. The anti-NoV mAb was prepared by immunizing P particles of GII.4 NoV in our previous experiment, it could react with GII.2, GII.3, GII.4, GII.6, GII.17 NoVs and be used in enzyme linked immunosorbent assay (ELISA) and colloidal gold immunochromatographic assay (Gao et al., 2021).