Mosquito Surveillance

Larval Surveillance

The Standing Water Initiative conducts larval mosquito surveillance across the county.  Areas of standing water are “dipped” to determine the presence of mosquito larvae.  If mosquito larvae are present and the area is on county property, the water is treated with  an environmentally friendly mosquito larvicide, such as Bti.  Each site is documented and monitored regularly through mosquito season (April – October).  If mosquito breeding sites are found on private property, county inspectors will educate and encourage property owners how to keep these sites mosquito-free.


Adult Surveillance

The Standing Water Initiative conducts adult mosquito surveillance at  97 sites across the county.  Adult mosquito surveillance measures the numbers of mosquitoes in an area and we are primarily interested in those species that can transmit diseases or those that are a nuisance to citizens.  We currently use two types of traps, the CDC light trap and the gravid trap.

The CDC light trap uses dry ice to attract mosquitoes in search of a blood meal.  The gravid trap uses a home-made liquid bait to attract gravid (ready to lay eggs) female mosquitoes.

Adult mosquito traps are set 4 nights per week in different locations.  They are collected the following day.  The collected mosquitoes are identified, counted and recorded into a computer database.  Certain mosquito species (those that are known vectors for West Nile virus) are pooled together and tested for West Nile virus.

Mosquito traps are not a form of mosquito control. They do not eliminate or reduce the mosquito population in an area. They are only used to capture a sample of the mosquitoes in an area to determine what species are residing there, and if they carry West Nile virus.


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Contact Us

Public Works

Henrico Department of Public Works
4305 E. Parham Rd.
Henrico, VA 23228

(804) 501-4393

[email protected]

Mailing Address
P. O. Box 90775
Henrico, VA 23273-0775

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