Even though Ada County has no reported human cases of West Nile virus this year, mosquitoes at nearly one-third of test sites around the county have tested positive for the virus, particularly in the northwest area of the county.
To combat the increasing number of infected mosquitoes and reduce the high probability of human infection, the county this week will aerially spray a pesticide.
The aerial spray area encompasses about 24,000 acres in northwest Ada County, including much of Meridian, Star and a portion of Eagle.
Spraying could begin as early as Thursday depending upon weather and wind conditions. Flights to conduct the aerial application will run from about 9 p.m. to midnight over the course of one or two evenings.
We want to make sure we get ahead of West Nile before someone in our community gets infected, said Meridian Mayor Tammy de Weerd at a press conference Wednesday. Mosquito abatement officials monitoring and controlling mosquito populations at approximately 100 locations throughout Ada County report a significant number of mosquitoes being trapped are testing positive for West Nile. As of Wednesday, 36 different testing pools at 26 locations have produced mosquitoes carrying the virus.
Statewide, 10 Idaho counties have reported mosquitoes testing positive for West Nile, and three counties in southwest Idaho (Washington, Payette and Owyhee) have reported human infections of West Nile, as well as a nearby Malheur County in eastern Oregon.
Mosquito abatement officials say they are seeing the level of West Nile infection in mosquitoes at approximately 25 per 1,000 mosquitoes in northwest Ada County. This level is about five times beyond the amount for which the state recommends advanced treatment methods such as aerial spraying.
Although we havent seen any human cases in Ada County yet this year, we cant wait until people are getting sick or worse to take action, said Brian Wilbur, Director of Ada County Weed, Pest & Mosquito Abatement. The company contracting with Ada County to conduct the aerial spray application, Vector Disease Control, is the same company that conducted aerial spray applications in Ada County back in 2006 when West Nile Virus first hit the nation.
The pesticide being used, Dibrom concentrate, was also used in the 2006 aerial application, and is specifically developed for use in heavily populated areas, according to the county. About 90 gallons will be used to cover the entire 24,000-acre area at an application rate of approximately only one-half of an ounce per acre.
The county assures the pesticide is virtually undetectable, dissipates by early morning, and is extremely effective in treating mosquitoes, but is not harmful to humans or pets. The spraying will take place late in the evening so it will not affect such beneficial insects as bees. For those with home gardens, the county recommends rinsing produce prior to consuming it. Registered no-spray zones within the county of 40 acres or greater will not be sprayed during this application. In addition to the mosquito abatement measures officials are taking, the county also recommends individuals protect themselves and their families from mosquitoes by taking the following simple steps:
Avoid mosquitoes during their most active hours.
Cover up with long sleeves and long pants when outside.
Wear an EPA approved repellent containing DEET.
Keep screens in your home in good shape to keep mosquitoes out.
Check your property for standing water where mosquitoes breed (mosquitoes can breed in small amounts of water).