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Posted on: September 15, 2021

OC Vector Confirms Bird Samples from Yorba Linda infected with West Nile Virus

Orange Country Mosquito and Vector Control Finds West Nile Virus in Bird Sample From Yorba Linda

The Orange County Mosquito and Vector Control District (OC Vector) has informed the City that a bird sample infected with West Nile virus (WNV) has been found in the City of Yorba Linda. All residents, park guests, sports leagues, and anyone spending time outside are advised to take precautions and wear mosquito repellents when mosquitoes are most active (dawn or dusk). We urge residents to take charge of their yards by dumping and draining standing water, tossing unused containers, and reporting green pools to OC Vector. Residents can request an inspection if they cannot find breeding sources but are still experiencing mosquito activity. Additionally, the following recommendations can help prevent mosquito bites:

  • Eliminate any standing water around your house. Many mosquitoes breed in small water sources in residential backyards, and they do not fly far from the source. Eliminating these small water sources can reduce the number of mosquitoes on your property. Search around your property for any standing water (indoors and out) and discard unused containers. Be sure to scrub unused containers thoroughly to remove mosquito eggs;
  • Make sure all window and door screens on your house are in good repair;
  • Wear a repellent containing DEET®, Picaridin, Oil of Lemon Eucalyptus, or IR3535;
  • When outdoors, wear long clothing that covers arms and legs; and
  • Contact the Orange County Mosquito and Vector Control District to report dead birds or neglected pools.

What is West Nile Virus?

West Nile virus (WNV) is a mosquito-borne disease that was originally found in Africa. In 1999, it was detected in the eastern United States; since then the virus has spread throughout the United States and is well established in most states, including California. WNV affects the central nervous system. However, symptoms vary:

No symptoms in most people: Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms.

Milder symptoms in some people: Up to 20 percent of the people (about 1 in 5) who become infected will display symptoms which can include fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach, and back. Symptoms generally last for just a few days, although even previously healthy people have been sick for several weeks.

Serious symptoms in a few people: Less than one percent of individuals (about 1 in 150 people) infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. WNV infection can be fatal.

Helpful Links

Links to guide you to a bite-free yard:

For more information about West Nile Virus or mosquito resources, please visit

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