The 2001 outbreak of foot-and-mouth disease in the United Kingdom is most often traced to:

• A. From improperly heat-treated pig swill
• B. From an illegally imported infected pig
• C. From a legally imported infected pig
• D. From contaminated slaughterhouse waste

Answer: (A)

Feeding contaminated animal products to pigs is a high-risk route for introducing foot-and-mouth disease because the virus can survive in undigested scraps if they aren’t heated enough to inactivate it. In the 2001 UK outbreak, investigators found that the initial farm’s pigs had been fed swill containing meat products that had not undergone sufficient heat treatment. This allowed the FMD virus to establish infection in a pig herd, from which it spread to other farms through usual transmission routes such as animal movement and shared equipment. While other pathways like illegally imported animals or slaughterhouse waste can contribute under different circumstances, the epidemiology of this outbreak pointed most strongly to improperly heat-treated pig swill as the source.