Immature Mosquito Surveillance
The immature stages (egg, larva, and pupa) of mosquito development require the presence of stagnant water. The stagnant water can be in a container as small as a bottle cap to a wetland of many acres in size. The most common method used to determine if water is breeding mosquitoes is referred to as dipping.
Adult Mosquito Surveillance
Three types of traps are utilized to conduct adult surveillance throughout Montgomery County. The traps give us information on mosquito population, species present, effectiveness of control measures, and viral activity.
The BG-sentinel trap utilizes lures which closely imitate the odors of human skin. This trap is very successful in collecting hard-to-trap daytime biting mosquitoes. This trap is set on ground level and away from direct sunlight.
The light trap simulates a live host for mosquitoes seeking a blood meal. It takes advantage of the mosquito’s ability to zero in on carbon dioxide emitted from the host's exhaled breath. Dry ice, which is the solid form of carbon dioxide, is used to mimic a host's exhaled breath and functions as the primary attractant for this trap. Light traps are hung from tree branches or fence posts, usually around eye level.
The gravid trap is designed to capture female mosquitoes looking for a location to deposit their eggs. A container of highly organic, foul smelling water, which mosquitoes find irresistible, is used to attract the gravid (pregnant) female mosquitoes. This trap is set on the ground in shaded areas and is highly effective in attracting mosquitoes from the Culex genus, the primary vectors of West Nile Virus.