Mosquito Spraying Planned This Week In Riverside County Following Positive Test Results For West Nile Virus

RIVERSIDE COUNTY, CA — Health officials are planning truck-mounted mosquito spraying in three areas of Nuevo following positive test results for the West Nile virus.

The Riverside County Vector Control Program will conduct ultra-low-volume ground applications on Thursday, Oct. 8, between 4:30 a.m. and 7:00 a.m., weather permitting.

The treatment zones cover nearly 300 combined acres:

• Mystic Field Area: A 49.5-acre zone bordered by Reservoir Avenue to the north, Orange Street to the east, Lakeview Avenue to the south and Magnolia Avenue to the west.
• East Nuevo Area: A 77-acre zone bordered by Reservoir Avenue to the north, Fifth Street to the east, East Lakeview Avenue to the south and Sixth Street to the west.
• West Nuevo Area: A 172-acre zone bordered by Ninth Street to the north, Yucca Avenue to the east, Tenth Street to the south and Reservoir Avenue to the west.

Crews will use Aqua Reslin, an EPA-approved mosquito control product, applied at a rate of 0.5 ounces per acre by trained technicians, according to the county.

While officials noted the product poses very low to no risk to humans and animals, residents and pets in the treatment zones are advised to remain indoors, close windows, turn off window-mounted air conditioners, and bring pet dishes and toys inside during the spraying and for 15 minutes afterward.

Notification signs will be posted along the treatment routes starting Tuesday, Oct. 6.

"The detection of West Nile virus in a local mosquito pool reminds us of the importance of working together to reduce mosquito activity and protect our families, neighbors and communities," said Fifth District Supervisor Yxstian Gutierrez.

Riverside County has reported three human cases, 12 positive dead birds, and 71 positive mosquito samples for West Nile virus during the 2026 season.

Statewide, California has reported 252 human cases of West Nile virus across 23 counties in 2026, according to the California West Nile Virus tracking portal.

Vector Control staff are increasing surveillance, checking breeding sites and performing larval control. Officials urged residents to protect themselves by using EPA-registered insect repellents, wearing long sleeves and pants, avoiding outdoor activity at dawn and dusk, and eliminating standing water around homes.

Residents can report mosquito problems, ask questions, or request mosquito-eating fish by calling the Riverside County Vector Control office at 951-766-9454 or visiting rivcoeh.org/vector-control.