Which disease was eradicated in the United States due to animal research?

• A. Smallpox
• B. Polio
• C. Measles
• D. Rabies

Answer: (A)

Vaccination, developed and continually refined with the help of animal research, can lead to full elimination of a disease. Smallpox is the standout example: its vaccine originated from observations and work involving animals (cowpox) and was later tested and improved through research, including animal models, to ensure safety and effectiveness. This combination of vaccine science and rigorous testing made global eradication possible, so the United States was able to eliminate smallpox as part of that worldwide effort. The other diseases—polio, measles, and rabies—have not been eradicated; they remain controlled or present in certain populations or animal reservoirs, so they don’t fit the scenario described.