Following detection of mosquitoes carrying West Nile virus, Riverside County vector control officials will conduct anti-mosquito spraying in Nuevo, covering a total of 300 acres, to eradicate growing infestations that pose a potential risk to public health.
The Department of Environmental Health has scheduled “ultra-low volume” insecticide spraying between 4:30 a.m. and 7 a.m. Tuesday in the following three locations:
— Mystic Field, specifically the area bounded by Lakeview Avenue to the south, Reservoir Avenue to the north, Orange Street to the east and Magnolia Avenue to the west;
— East Nuevo, bounded by Reservoir to the north, Lakeview to the south, Fifth Street to the east and Sixth Street to the west;
— And the largest space, covering 172 acres, encompassing portions of west Nuevo, specifically Ninth Street to the north, 10th Street to the south, Reservoir to the west and Yucca Avenue to the east.
This same area has been targeted numerous times in recent years for spraying, always at the height of summer. According to Department of Environmental Health spokeswoman Sandi Salas, concentrations of mosquitoes tested positive for West Nile virus, raising concerns about the potential for transmission.
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.
One human WNV infection has been documented in the county so far this year. Additionally, statewide, 30 infections have been recorded to date in 2026, according to the California Department of Public Health. Three of those, in Northern California, resulted in fatal outcomes.
In 2025, one human WNV infection was documented in Riverside County, and the patient recovered.
The Department of Environmental Health stated that a dead bird recovered recently in the vicinity of Spencer Park, near Murrieta, tested positive for WNV. However, the discovery has not been linked to any infestations, so officials are holding off for now on spraying.
“Vector control staff are increasing surveillance in the Murrieta area, identifying potential breeding sites and conducting larval control where needed,” the agency said.
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 with WNV, residents are urged to:
— Spend as little time as possible outdoors at dawn or dusk, when mosquitoes are generally on the move;
— Wear long pants and long-sleeved shirts during outdoor activity in mosquito-prone areas;
— 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.
Additional information is available at rivcoeh.org/vector-control.