The District has an extensive mosquito trapping program used to monitor mosquito populations and to detect diseases. Different types of traps are used depending on the environment, the species to be trapped, and the type of data needed.
Each summer, surveillance for West Nile virus ramps up as the weather warms. The District uses three surveillance techniques to guard against West Nile virus (WNV) outbreaks: trapping adult mosquitoes, collecting dead birds, and monitoring two sentinel chicken flocks.
Dead birds and squirrels are often the first indicator that West Nile virus exists in an area.