What is the primary purpose of public health surveillance?

• A. Monitor health events and detect trends
• B. Treat diseases in individuals
• C. Provide clinical care
• D. Allocate resources

Answer: (A)

Public health surveillance is the ongoing process of collecting, analyzing, and interpreting health data to watch for patterns in health events over time. Its main job is to detect changes in disease frequency, identify outbreaks or emerging threats, and monitor trends so public health authorities can respond quickly and put prevention and control measures in place. For example, watching the rise and fall of influenza-like illness across communities helps spot unusual spikes and trigger investigations or vaccination efforts. While the data from surveillance can guide decisions about where to focus resources or clinical services, the central aim is monitoring and trend detection to inform action, not treating individuals or delivering clinical care.