A study conducted by Carpenter, OBrien, Hagerman and McCarl in 2011 estimates the economic impact of a foot and mouth disease (FMD) epidemic in the United States to be $2.3$69.0 billion. We simulate an outbreak of FMD across central California using the InterSpread Plus simulation package. We use an experimental design that produces 102,400 epidemic simulation runs. Using the data from the simulations, we identify 16 critical disease and control parameters that have the greatest effect on the spread of FMD. A statistical model based on these 16 parameters and their interactions captures approximately 85% of the variability of the simulation model. The main takeaways of our analysis of FMD spread are as follows. The two most critical disease parameters are initial condition and local spread. The most critical disease control parameters are market movement and surveillance. Our experimental results indicate that if a typical premise sends an animal to market every 2.2 days instead of every day, we will see a 25% reduction in the mean number of cattle infected. Similarly, if there is less than a three day delay in between suspecting an FMD outbreak and declaring an FMD outbreak at dairy-like facilities, we see a 50% reduction in the number of infected cattle. Control measures cannot be taken in isolation. Our models show significant interaction effects between the most effective control measuresmarket movement, and surveillance and other control measures such as tracing, vaccination and depopulation.

Subjects: Central California; Foot and mouth disease; disease modeling software; InterSpread Plus; simulation model; design of experiment; NOB; disease parameters; control parameters; regression model; partition tree model; sensitivity analysis