NRAS and infection: To identify whether one of the viral protein(s) could itself induce increased intestinal contractions upon a HuNoV infection, zebrafish larvae were inoculated with virus-like particles (VLPs) containing the VP1 and VP2 capsid proteins (or only VP1), or with the HuNoV non-structural (NS) proteins NS1/2 (N-term), NS4 (p22), NS6 (Pro) and NS7 (RdRp).