When an infectious disease spreads among a colony of rodents, what is often the most effective method to eradicate it?

• A. A cocktail of antibiotics
• B. A combination of antivirals and antibiotics
• C. Depopulation
• D. Quarantine

Answer: (C)

When an infectious disease spreads through a rodent colony, removing the entire population is often the most reliable way to stop transmission and eliminate the infection. Depopulation directly removes all potential carriers and environmental reservoirs, breaking the chain of transmission quickly in a high-density setting. Treatments like antibiotics or antivirals may help with illness in individual animals, but they rarely eradicate all carriers or fully clear the pathogen from a colony, and some pathogens persist in the environment or among asymptomatic animals. Quarantine can slow spread, but once an outbreak is established across the colony, it won’t eradicate it on its own. After depopulation, thorough cleaning, disinfection, and rederivation or introduction of disease-free stock, with strict biosecurity, are essential to prevent reintroduction.