Mosquitoes carrying West Nile virus have been found in Newport Beach, part of a countywide spike that saw positive samples more than double in a single week, according to data released Wednesday, July 8.
The Orange County Mosquito and Vector Control District reported 38 virus-positive mosquito samples across 13 cities, up from 18 samples the week before. Newport Beach has one confirmed positive sample. Fullerton leads the county with 15.
The district first detected infected mosquitoes in Newport Beach on Monday, June 2, making it one of the earliest detections this season. The July 8 data shows the virus has since spread to a dozen other cities, including Costa Mesa, Huntington Beach, and Seal Beach.
"We are above-average for this time of year," Miquel Jacobs, the district's director of communications, told the Los Angeles Times.
A 20-year high nationwide
The surge extends well beyond Orange County. West Nile virus is off to its earliest start in the United States in two decades, according to CDC surveillance data. As of Tuesday, June 30, at least 48 human cases had been reported nationwide, including 38 cases of severe neuroinvasive disease, the highest midyear count since 2004.
Three confirmed human cases have been reported in California this year: one in Los Angeles County, one in Sacramento County, and one in Long Beach. No human cases have been reported in Orange County so far.
For context, the district detected West Nile virus in just four mosquito pools during all of 2025, five in 2024, and one in 2023. This year's 38 positives by early July dwarf those full-season totals.
What Newport Beach residents should do
The district is urging residents to take these steps:
- Dump and drain containers holding standing water at least once a week
- Clean and scrub bird baths and pet water bowls weekly
- Repair broken or damaged window and door screens
- Wear repellent containing DEET, picaridin, IR3535, or oil of lemon eucalyptus, especially at dawn and dusk
- Wear light-colored, loose-fitting long sleeves and pants outdoors during peak mosquito hours
People over 50 and those with preexisting health conditions face the highest risk of serious illness. About 80% of those infected show no symptoms. Roughly 1% develop neuroinvasive disease such as encephalitis or meningitis, which can cause permanent brain damage or death.
Treatment response
The district dispatched truck-mounted spraying crews to a 4.5-square-mile section of Fullerton between Friday, July 10, and Sunday, July 12, treating between 1 a.m. and 5 a.m. each night. District officials told KTLA they spray only when both mosquito abundance and disease presence trigger action.
The district offers free property inspections. Residents can call (714) 971-2421 or (949) 654-2421, or visit ocvector.org to request one.
