Mosquitoes found with West Nile virus in Costa Mesa as Orange County logs 3 human infections

Robert Cummings of the O.C. Mosquito and Vector Control District
Robert Cummings of the O.C. Mosquito and Vector Control District collects mosquitoes from a trap at Big Canyon in Newport Beach. The agency found mosquitoes with West Nile virus in Costa Mesa on Aug. 28.
(Courtesy of the Orange County Mosquito and Vector Control District)

A mosquito sample collected in Costa Mesa’s Fairview Park has tested positive for West Nile virus, marking the first mosquito infection inside city limits this year, according to officials with the Orange County Mosquito and Vector Control District.

Traps were laid out in the park on Aug. 27 as part of a weekly countywide surveillance program and collected on Aug. 28. By Tuesday, a positive testing result had been confirmed, district spokeswoman Heather Hyland said Wednesday.

“We can’t really say how many mosquitoes were positive,” Hyland said, adding that the trap that was set in Fairview Park contained 13 mosquitoes, which were collectively tested.

Once the presence of the virus has been confirmed, Hyland said district staff inform city officials and then notify the public of their findings online and through social media channels.

Two efforts, one examining a reduction in council members’ salaries and the other a resolution supporting a city-sponsored ballot measure to allow the sales and delivery of retail cannabis, were hotly discussed Tuesday.

In a release issued Wednesday, district officials warned residents to exercise caution around areas where mosquitoes can breed.

“West Nile virus positive mosquito samples indicate that the virus is active in Orange County and there is an increased risk for residents to become infected with [the virus] through a mosquito bite,” Scientific Services director Robert Cummings said in the statement.

As of Aug. 27, the Orange County Health Care Agency had confirmed three cases of human infection — a male minor who’d been diagnosed with a neuroinvasive form of the virus and two females between the ages of 18 and 49 identified as being infected with non-neuroinvasive cases.

Ten other human West Nile virus cases have been confirmed statewide in 2020, eight in Stanislaus County, and the others in L.A. and Madera counties.

Humans are typically infected with West Nile virus when bitten by an infected mosquito. Mosquitoes become infected by feeding on birds that already have the virus.

While an estimated 80% of infected individuals never show symptoms, some may experience fever, headache and body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach and back.

To prevent mosquito bites, residents are encouraged to dump and drain containers of water at least once each week, clean and scrub bird baths and pet water bowls weekly and keep potted plant saucers free of excess water. For more information on West Nile virus, visit

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