West Nile Virus Cases Are Up in Los Angeles County
According to the Los Angeles County Department of Public Health, 100 West Nile virus infections had been reported as of September 17. That's up from 22 during all of 2025.
Those numbers don't include Long Beach or Pasadena, which have their own health departments.
Long Beach has been particularly affected this year. As reported by the Los Angeles Times, the city had reported 42 cases as of September 22.
Orange County Is Seeing Elevated West Nile Activity, Too
When we wrote about West Nile virus in Orange County in July, mosquito testing was already showing substantially more activity than the year before.
That trend has continued.
By mid-September, the Orange County Mosquito and Vector Control District had recorded 747 West Nile-positive mosquito samples in 2026, compared with 186 during all of 2025.
Positive mosquito samples have been found in communities throughout the county, including Anaheim, Fullerton, Huntington Beach, Santa Ana, Garden Grove, Costa Mesa, Orange, and others.
Why Are Mosquitoes Still So Active?
Southern California's weather is part of the story.
Unusually warm and humid conditions this summer have been favorable for mosquitoes. Humidity can help adult mosquitoes survive longer, while warm temperatures support continued activity.
El Niño conditions have contributed to some of Southern California's unusual weather this year, but weather alone doesn't determine West Nile activity. Temperature, humidity, standing water, mosquito populations, and the amount of virus circulating among birds can all influence a season.
What Can You Do Around Your Home?
West Nile virus is primarily spread through the bite of an infected mosquito. Most people who become infected don't develop symptoms, while a much smaller percentage develop serious illness.
The practical response is to reduce opportunities for mosquito bites and breeding around your property.
Start with standing water. Mosquitoes don't need a neglected swimming pool or large puddle to reproduce. Flowerpot saucers, buckets, children's toys, birdbaths, clogged gutters, tarps, and other outdoor items can all hold water.
Walk around your property regularly and dump water where you find it. Scrub containers before refilling them, check window and door screens for damage, and use an EPA-registered mosquito repellent when spending time outdoors.
Pay particular attention after irrigation or rain, when items around the yard may be holding water that wasn't there before.
Ongoing Mosquito Control Can Help Reduce Activity Around Your Home
Even if you're diligent about standing water, you can't control what's happening on neighboring properties or elsewhere around your community.
Admiral Pest Control's Ultimate Pest & Mosquito Service combines seasonal mosquito control with ongoing protection from common household pests for homes throughout Los Angeles and Orange counties.
Mosquito treatments target areas around the property wher
