The 2001 epidemic of foot and mouth disease in the United Kingdom probably originated:

• A. From improperly heat-treated pig swill
• B. From an illegally imported infected pig
• C. From a legally imported pet hedgehog
• D. From a legally imported infected pig

Answer: (A)

The key idea is how foot-and-mouth disease virus can enter a pig herd through contaminated feed. The virus is highly contagious among cloven-hoofed animals and can survive in meat products if they aren’t heated long enough to inactivate it. In the 2001 UK outbreak, investigators concluded that pig swill—food waste containing pork products—was fed to pigs without adequate heat treatment, allowing the virus to survive and infect the herd. That route matches the pattern of introduction and rapid spread seen in the outbreak. Legally imported infected pigs would have been detected by controls, and an illegally imported pig or a pet hedgehog are less plausible sources given how the outbreak began and the biology of the virus. So, improper heat treatment of pig swill is the most likely origin.