Noroviruses are the main cause of diarrhea/vomiting illness in Canada. Oyster-associated norovirus outbreaks have been reported more frequently in recent years; the largest, affecting 449 individuals, was linked to British Columbia-harvested oysters in 2016/2017. The stakes are high in investigations of oyster-associated outbreaks; failure to identify contaminated oysters can result in many illnesses while inaccurately identifying oysters as the cause of illnesses can result in shellfish growing area closures at a high cost to producers. Laboratory data is important in outbreak investigations, for making the link between human illness and contaminated food. Currently in B.C., surveillance and outbreak investigations of noroviruses in oysters are conducted with incomplete laboratory data, since noroviruses cannot easily be grown in a laboratory and are often in low concentrations in contaminated oysters. Therefore, it is imperative to improve laboratory methods to understand the sources of norovirus and reduce the burden of oyster-associated illnesses. We are proposing the Unified Pathogen Control One Health Approach Specifically Targeting Norovirus (UPCOAST-N), a program that will develop new methods to improve investigations of oyster-associated norovirus illnesses. We will develop a One Health target enrichment sequencing assay suitable for both human and oyster samples. This method will be able to determine the type of norovirus found in oysters and can characterize the genome of norovirus found in oyster and human samples. These methods will be evaluated on archived and new samples, building on existing monitoring programs. The cross-sectoral work will benefit key end-users including the BCCDC, Health Authorities, Ministry of Agriculture, CFIA and industry, by: A) improving food safety, supporting the agri-foods industries to make a safer product; B) reducing the incidence of oyster-associated norovirus through improved monitoring, outbreak response and targeted recalls/closures of shellfish growing areas; and C) developing approaches that can be applicable to other sample types (i.e. sewage and water).