This is the first detection of West Nile virus within the Greater Los Angeles County Vector Control District service area for this year.

Santa Fe Springs, CA (July 23, 2025) – The Greater Los Angeles County Vector Control District (GLACVCD/District) has confirmed the first mosquito samples to test positive for West Nile virus (WNV) in Los Angeles County this year. The positive samples were collected from mosquito traps in Arleta, South El Monte, and Valley Glen, confirming the presence of the virus in mosquito populations within the community. Subsequent testing has confirmed three additional WNV positive mosquito samples collected in Van Nuys, Panorama City, and Lake Balboa. This brings the total number of detections to six so far this year in the District’s service area.

“West Nile virus is a mosquito-borne disease transmitted to people through the bite of an infected Culex mosquito,” said Steve Vetrone, GLACVCD Assistant General Manager of Vector Management. “The virus is endemic to Los Angeles County with activity typically increasing during the summer months.”

The native Culex mosquito is most active during dawn and dusk. West Nile virus is the most common mosquito-borne disease in Los Angeles County and is naturally found in the environment across the entire county, even in areas where recent mosquito sample detections have not occurred. Because there is currently no human vaccine for the virus, residents must take personal protective measures by using mosquito repellent when spending time outdoors, especially during peak mosquito activity. The Centers for Disease Control and Prevention recommend using insect repellent with any of the following active ingredients: DEET, Picaridin, IR3535, or Oil of Lemon Eucalyptus. These ingredients have been proven safe and effective when used as directed.

“While we continue to monitor and treat public spaces, we rely on residents to help reduce mosquito breeding in their properties,” added Vetrone. “Dumping out standing water and wearing mosquito repellent are simple but powerful ways to stay protected.”

Mosquito control is a shared responsibility, and residents must take an active role in reducing the threat of WNV in their neighborhoods by taking these additional steps:

• Eliminate standing water in clogged gutters, rain barrels, discarded tires, buckets, watering troughs or anything that holds water for over a week.
• Ensure that swimming pools, spas, and ponds are properly maintained.
• Change the water in pet dishes, bird baths, and other small containers weekly.
• Request mosquitofish from your local vector control district for placement in ornamental ponds.
• Report neglected (green) swimming pools in your neighborhood to your vector control district.

For an extensive list of common indoor and outdoor sources and recommended solutions, visit bit.ly/diy-mosquito-solutions. For more information, residents can contact the Greater Los Angeles County Vector Control District at 562-944-9656, online at www.GLAmosquito.org, or on social media: Facebook, X, Instagram, Nextdoor, and YouTube.

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About West Nile virus (WNV):
WNV is transmitted to people and animals through the bite of an infected mosquito. There is no cure for WNV. One in five persons infected with the virus will exhibit symptoms. Symptoms can include fever, headache, body aches, nausea, or a skin rash. These symptoms can last for several days to months. One in 150 people infected with the virus will require hospitalization. Severe symptoms include high fever, muscle weakness, neck stiffness, coma, paralysis, and possibly death.

About GLACVCD:
The Greater Los Angeles County Vector Control District is an independent Special District and public health agency formed under the authority of the California State Health & Safety Code. Our mission is to promote healthy communities within the District's service area by countering the threat of mosquito and other vector-borne diseases through exceptional service, rigorous surveillance strategies, conscientious control measures, and comprehensive education efforts.