Environmental surveillance results monitor poliovirus presence in which setting?

• A. Clinical laboratories
• B. Hospital admissions
• C. Water and sewage systems
• D. Household surveys

Answer: (C)

Environmental surveillance relies on wastewater testing to detect poliovirus shed by people in the community. Because poliovirus is excreted in feces, sampling water and sewage systems provides a population-wide signal, often catching circulation before clinical cases appear and helping track transmission and vaccine-derived strains. Other surveillance methods focus on individuals—clinical laboratories test specimens from patients, hospital admissions capture clinical cases, and household surveys collect information but do not measure virus presence in the environment.