Overview and Disclaimer

Welcome to the NSRA tool. This tool accompanies the manuscript titled “Risk assessment of norovirus illness from consumption of raw oysters in the United States and in Canada” published in Risk Analysis. (DOI: 10.1111/risa.13755) (link will open in a new tab).

Manuscript Abstract

Human norovirus (NoV) is the leading cause of foodborne illness in the United States and Canada. Bivalve molluscan shellfish is one commodity commonly identified as being a vector of NoV. Bivalve molluscan shellfish are grown in waters that may be affected by contamination events, tend to bioaccumulate viruses, and are frequently eaten raw. In an effort to better assess the elements that contribute to potential risk of NoV infection and illness from consumption of bivalve molluscan shellfish, the US Department of Health and Human Services/Food and Drug Administration (FDA), Health Canada (HC), the Canadian Food Inspection Agency (CFIA), and Environment and Climate Change Canada (ECCC) collaborated to conduct a quantitative risk assessment for NoV in bivalve molluscan shellfish, notably oysters. This study describes the model and scenarios developed and results obtained to assess the risk of NoV infection and illness from consumption of raw oysters harvested from a quasi-steady-state situation. Among the many factors that influence the risk of NoV illness for raw oyster consumers, the concentrations of NoV in the influent (raw, untreated) and effluent (treated) of wastewater treatment plants (WWTP) were identified to be the most important. Thus, mitigation and control strategies that limit the influence from human waste (WWTP outfalls) in oyster growing areas have a major influence on the risk of illness from consumption of those oysters.

Access to the tool is provided to illustrate the model presented. Please refer to the manuscript for a full description of the methods, results, limitations and conclusions of the analysis.

Responsibility for the interpretation and use of the model and of the accompanying documentation lies solely with the user. Third parties' use of or acknowledgment of the system and its accompanying documentation, including through the suggested citation, does not in any way represent that US Food and Drug Administration, Health Canada, Canadian Food Inspection Agency, Environment and Climate Change Canada or JIFSAN or JIFSAN endorses such third parties or expresses any opinion with respect to their statements.

Suggested citation

Pouillot R., Smith M., Van Doren J.M., Catford A., Holtzman J., Calci K.R., Edwards R., Goblick G., Roberts C., Stobo J., White J., Woods J.,DePaola Jr. A., Buenaventura E.,Burkhardt III W. (2021) Risk assessment of norovirus illness from consumption of raw oysters in the United States and in Canada. Risk Analysis. DOI: 10.1111/risa.13755 (link will open in a new tab).

Instructions

Navigate from tab to tab to set the various parameters (Simulation setup, Influent, Waste Water Treatment Plant characteristics, Harvest Water (Estuary) characteristics, Shellfish characteristics, Meal characteristics, Dose Response). Once your set of parameters is defined:

• if someone has already launched the simulation with the same set of parameters, “Computed Results Available” will be indicated and the results will be available immediatly. click on the “Compute/Update Results” button to get those results.
• Otherwize, “To Be Computed” will be indicated. click on the “Compute/Update Results” button and wait until the simulation is done (see progress bars in the lower right corner).

In the “Input/Output” tab, you'll be able to get a report of the simulation, to save the current set of parameters or to upload a prviously saved set of parameters.