Six hours of "fogging" to combat the mosquito-borne West Nile Virus are set to begin at 11 p.m. tonight (Monday, July 21) in an area that includes most of Ladera and, in Portola Valley, the Westridge neighborhood east of Westridge Drive on and around Alamos Drive.
Infected mosquitoes were found in Ladera on July 18, according to the San Mateo County Mosquito and Vector Control District. They were also found in the San Mateo area.
Spraying/fogging is done in a half-mile radius from the detection site, the district says.
The district frequently tests dead birds and squirrels for the virus. This is the first year mosquitoes carrying the the virus have been found in the county, District Manager Robert Gay said.
While the primary hosts are birds, humans, horses and other animals can be infected, according to the district. Among human victims, 80 percent show no symptoms at all, it says.
Infection requires the bite of an infected mosquito; the virus cannot be spread person-to-person.
About 1 percent of people bitten by an infected mosquito will develop serious symptoms, which can include high fever, headache, a stiff neck, disorientation, tremors, convulsions, muscle weakness, numbness, vision loss, coma and paralysis. Neurological damage can be permanent, the district says, and the disease has the potential to be fatal.
To reduce the likelihood of mosquitoes around the house, the district recommends that residents drain all standing water; avoid being outside without protective clothing at dawn or dusk, when mosquitoes are most active; and use repellants that contain DEET, picaradin, oil of lemon eucalyptus or IR3535.
Go to westnile.ca.gov for more information.
Go to this link for a copy of the map of the area to be fogged tonight.