Adult Surveillance

The District Science Department handles the surveillance and identification of adult female mosquito populations. These population counts are utilized in determining areas that need treatment with ultra-low volume (ULV) adulticide applications to lower nuisance and vector species.

The CDC light trap is the main type that is used to surveillance adult populations. The traps are hung above the ground and left overnight. These traps use light and CO2 gas as attractants, luring female mosquitoes to fly close enough to be suck into the collection chamber with a fan. Currently, the District deploys 25 CDC light traps throughout the county.

BG Sentinel traps are collapsible traps that sit directly on the ground. These traps use co2 gas as an attractant as well but also use a BG lure that mimics the smell of stinky feet. BG Sentinel traps are important in surveillance of domestic Aedes species that live near homes, prefer to feed on humans, and can vector arboviruses such as Dengue, Chikungunya, and Zika.

Passive-baited traps are large plastic boxes baited with CO2 gas that are hung off the ground. These traps do not have a fan that sucks in the mosquitoes. Instead the female mosquitoes “passively” fly through an opening at the bottom and cannot escape back out. Female Culex nigripalpus are the main species captured by passive-baited traps. The females are used ovarian dissection.

Aspirators are contraptions that have a long tube attached to a fan that is used to vacuum resting mosquitoes from plants in the early morning hours. An operator wears a backpack carrying a battery and swipes the aspirators on and under leaves of plants to capture the mosquitoes. This method of collection allows for the identification of species that are not as attracted to light or CO2 gas.

Gravid traps are unique traps that utilize a black tray of stinky water as the attractant for domestic Culex females carrying eggs. Domestic Culex species are important vectors of West Nile Virus, St. Louis Encephalitis, and Eastern Equine Encephalitis. As females come to try and land on the water to lay her eggs, a fan sucks them up. These traps will be placed near sentinel chicken sites to monitor vector species.