Further detection of mosquitoes carrying West Nile virus prompted Riverside County vector control officials to schedule anti-mosquito spraying in Nuevo on Thursday, covering a total 300 acres.
The Department of Environmental Health has slated “ultra-low volume” insecticide spraying between 4:30 a.m. and 7 a.m. Thursday 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.
The same area was targeted for spraying in August, and has repeatedly been the focus of eradication operations in recent years, most typically during summer. According to department spokeswoman Sandi Salas, concentrations of mosquitoes tested positive for West Nile virus, raising concerns about the potential for transmission.
Riverside County Supervisor Yxstian Gutierrez said the current effort is aimed at “keeping our community safe and healthy.”
“This targeted treatment is one of the steps being taken to help reduce the risk of West Nile virus transmission,” he said. “We encourage everyone to do their part by preventing mosquito bites and removing standing water around their homes.”
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 pickups. Officials recommended that during operations, residents stay indoors and keep windows closed until at least 15 minutes after the trucks have departed.
Three human WNV infections have been documented in the county so far this year. Statewide, 252 infections have been recorded to date in 2026, according to the California Department of Public Health. Nineteen of those resulted in fatal outcomes — none in the Inland Empire.
In 2025, one human WNV infection was documented in Riverside County, and the patient recovered.
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.