Simulated Effects of Introducing Emergency Vaccination or Depopulation During FMD Outbreaks in Denmark

The purpose of this study was to explore the effects of modifying FMD control 14 days following detection of the first infected herd in a simulated FMD epidemic in Denmark. The spread of FMD was simulated using an adapted version of the well described DADS simulation model, called DTU-DADS, using Danish herd locations and movements data.

The epidemics were initiated in 1000 randomly chosen cattle herds located in cattle-dense areas. The basic scenario consisted of: the minimum EU control measures, culling of forward-traced herds and a 3-day national stand-still on animal movements. Alternative scenarios included depopulation, suppressive or preventive vaccination within 1 km.

The results show that there may be positive effects of applying additional control measures on the size, duration and costs of the epidemics. The median duration decreased from 56 days in the basic scenario to 45-47 days in the vaccination scenarios, and to 40 days in the depopulation scenarios. Furthermore, the number of infected herds decreased, but with fewer infected herds in the protective vaccination scenario.

The total costs of an epidemic, including export losses, changed from €562 million in the basic scenario to €515, €535 and €610 million in the depopulation, suppressive and protective vaccination scenarios, respectively. These results suggest that vaccination will often be a more expensive strategy in a country with a large export, like Denmark.

Furthermore, the simulated results show that from an economic point of view depopulation in zones is often preferable.