LA County reports first sample of West Nile virus of 2024

A West Nile virus mosquito sample has been confirmed in Los Angeles County, officials said Saturday – the first positive sample in Los Angeles County this year.

The sample was collected from a mosquito trap in the Winnetka area of the San Fernando Valley, confirming the presence of the virus in mosquito populations within the community.

"While the presence of West Nile Virus in our community is not unusual, this early detection serves as a critical reminder for all residents to take preventative actions," said Steve Vetrone, director of scientific- technical services for the Greater Los Angeles County Vector Control District.

"We urge everyone to protect themselves from mosquito bites and to eliminate standing water around their homes where mosquitoes can breed."

Officials said the native Culex mosquito is capable of transmitting West Nile virus and is most active during dusk and dawn. Because there is no human vaccine for the virus, residents should be proactive against mosquito bites by wearing insect repellent. The U.S. Centers for Disease Control and Prevention recommends products with the active ingredients DEET, Picaridin, IR3535, or Oil of Lemon Eucalyptus.

Most humans who become infected with West Nile Virus generally experience no or mild symptoms, such as fever, muscle aches and fatigue. People over age 50 and those with chronic medical conditions can become more seriously ill, possibly affecting the brain and spinal cord, leading to meningitis, encephalitis or paralysis.

The GLACVCD also recommends taking these additional steps:

  • Eliminate standing water in clogged rain gutters, rain barrels, discarded tires, buckets, watering troughs or anything else 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.