Confirmation of West Nile virus among mosquitoes netted in Murrieta will require pest eradication operations over a nearly five acre space within the city this week, according to vector control officials.
The Riverside County Department of Environmental Health has scheduled "ultra-low volume" insecticide spraying in the area of Calvary Murrieta Christian School on Wednesday between 5 a.m. and 7 a.m.
Agency spokesman Brent Casey said a batch of mosquitoes that were caught in traps near the school, where the pests' numbers have been growing, tested positive for West Nile.
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Spray treatments are planned within an area bordered by Jackson Avenue to the north, Monroe Avenue to the south, California Oaks Road to the east and Interstate 15 to the west, he said.
Anti-mosquito spraying involves the use of chemicals approved by the U.S. Environmental Protection Agency. Pesticides are emitted as a mist dispersed from machines anchored in the backs of pickup trucks.
Officials recommended that during operations, residents stay indoors and keep windows closed until at least 15 minutes after the trucks have departed.
Two human West Nile virus infections have been documented in Riverside County so far this year. Statewide, a total of 46 WNV infections have been recorded, the largest number of them in Northern California, according to the California Department of Public Health. There has been one WNV-related death in Los Angeles County.
Mosquitoes typically become carriers of the virus after feeding on an infected bird and can then spread the potentially lethal strain to animals and humans. Those at greatest risk include seniors and individuals with compromised immune systems.
Symptoms may never materialize, but can include fever, headache, nausea, body aches, skin rashes and swollen lymph nodes.
Mosquito season in Southern California generally spans May to October.
To reduce exposure to mosquitoes carrying WNV, residents are urged to: -- spend as little time as possible outdoors at dawn or dusk, when mosquitoes are generally on the move;
-- wear pants and long-sleeved shirts during outdoor activity in mosquito-prone places;
-- use insect repellent;
-- ensure door and window screens are fitted properly to keep bugs out; and -- get rid of standing water, aside from pools properly treated with chemicals.
Anyone with concerns should contact the Department of Environmental Health at 951-766-9454.