West Nile Virus Detected in Sylmar - Mosquitos

Posted on 08/21/2026

The Greater Los Angeles County Vector Control District (GLACVCD) has confirmed the first mosquito sample to test positive for West Nile virus (WNV) in Sylmar this year. The WNV-positive sample was detected in mosquito traps in your community on August 14, 2026. District staff will place notices in public spaces within a half-mile radius around trap locations to advise residents to take precautions when mosquitoes are present.

Important WNV Information

West Nile Virus is transmitted to people and animals through the bite of an infected Culex mosquito, which is most active from dusk to dawn.

Approximately 1 in 5 people infected with West Nile Virus will develop symptoms

Symptoms include fever, headache, body aches, nausea, or a skin rash

Severe cases can lead to paralysis or even death

There is currently no human vaccine for West Nile Virus

Mosquito Prevention and Protection 

Mosquito control is a shared responsibility, and residents can help reduce the threat of West Nile Virus in their neighborhoods by taking the following steps:

Once a week, empty any items that hold water like buckets, planters, children's toys, discarded tires, birdbaths, plant saucers, or trash containers

Maintain swimming pools, spas, and ponds, and report neglected or green pools to vector control

Wear insect repellent when outdoors where mosquitoes may be present

Report dead birds to the California Department of Public Health online at https://westnile.ca.gov or call 1-877-WNV-BIRD (1-877-968-2473)

Homepage: Greater Los Angeles County Vector Control / Mosquito

https://www.glamosquito.org/

Further detailed information

A West Nile mosquito is not a single specific kind of insect. It refers to any mosquito—most often from the Culex genus—that carries and spreads the West Nile virus. These mosquitoes pick up the virus by biting infected birds and can pass it to humans and other animals through their bites.

How the Virus Spreads

Bird-Mosquito Cycle: The virus lives mainly in birds and the mosquitoes that feed on them.

Dead-End Hosts: Humans and horses can catch the virus from a bite, but they do not build up enough virus in their blood to pass it back to mosquitoes.