Transmission intensity and impact of control policies on the foot and mouth epidemic in Great Britain

The foot and mouth disease (FMD) epidemic in British livestock remains an o ngoing cause for concern, with new cases still arising in previously unaffe cted areas. Epidemiological analyses(1-3) have been vital in delivering sci entific advice to government on effective control measures. Using disease, culling and census data on all livestock farms in Great Britain, we analyse d the risk factors determining the spatiotemporal evolution of the epidemic and of the impact of control policies on FMD incidence. Here we show that the species mix, animal numbers and the number of distinct land parcels in a farm are central to explaining regional variation in transmission intensi ty. We use the parameter estimates thus obtained in a dynamical model of di sease spread to show that extended culling programmes were essential for co ntrolling the epidemic to the extent achieved, but demonstrate that the epi demic could have been substantially reduced in scale had the most efficient control measures been rigorously applied earlier.