Abstract for:Getting A Handle On Norovirus Foodborne Transmission Mechanisms: A study for the Food Standards Agency
We outline a range of modelling activities for UK’s Food Standards Agency (FSA). Norovirus produces infectious intestinal disease via person-to-person contact (P2P) and foodborne (FB) transmission. FSA commissioned a study to improve understanding of FB mechanisms, and of where it might focus its efforts. In response, a P2P model with a single, exogenous parameter for FB transmission was transformed into an SD model of FB processes. The modelling involved individual interviews and a group-modelling session (the FSA arranged access to key experts). Transmission routes modelled concerned: bi-valve shellfish; sludge; fruits and vegetables; other foodstuffs. This model represented the underlying causal mechanisms and facilitated a categorisation of parameters which was useful in agenda-setting for future research and in identifying policy levers. Creative thinking extended the work in a significant way. Mathematical analysis made it possible to calibrate a P2P model for the first time. Sensitivity analysis suggested that small changes in human behaviour could explain Norovirus seasonal variations, and offered an understanding of the relative importance of FB and P2P vectors. A range of actions resulted, including an increased understanding by the FSA of the different means of trying to control Norovirus, practical actions and ideas for further work.