What is the purpose of sentinel sites in vector surveillance?

• A. Sentinel sites release sterile insects.
• B. Sentinel sites act as refugia for mosquitoes.
• C. Sentinel sites provide longitudinal data on vector abundance and infection rates to detect trends and evaluate interventions.
• D. Sentinel sites are only used for climate data.

Answer: (C)

Sentinel sites are fixed monitoring locations where standardized sampling is conducted regularly to track mosquito populations and pathogen presence. By collecting data at the same spots over time, you can see how vector abundance and infection rates change with seasons, identify unusual trends, and evaluate how well control measures are working. This longitudinal view provides the basis for detecting trends and assessing the impact of interventions. The other options describe activities or roles that aren’t about ongoing data collection for trend analysis: releasing sterile insects is an control strategy, not surveillance; refugia are habitats, not data sites; climate data can be gathered separately and isn’t the primary purpose of sentinel surveillance.