Year's First Human Cases of West Nile Virus Found in Los Angeles County

Public health officials cautioned area residents to empty stagnant pools and try to avoid mosquito-prone areas

Five people have tested positive for West Nile Virus in Los Angeles County, marking the year’s first cases, according to public health officials.

Two adults were hospitalized earlier this month, and both patients were recovering. Three blood donors who were found to be infected with the virus did not become sick.

The five patients were from across the county, including the South Bay and San Fernando and San Gabriel valleys, according to the Los Angeles County Department of Public Health, which announced the infections Thursday.

The two hospitalized patients were a healthy adult with no medical history and an elderly person with chronic health conditions, the department said.

Last year, 174 human cases of the virus were found in LA County, the second-highest count since 2004.

As of July 23, 2013, only one other human case had been reported in California -- in Sacramento County -- according to state figures.

Director of Public Health Dr. Jonathan Fielding urged county residents to take precautions to avoid getting bitten by infected mosquitoes, which transmit the virus to humans.


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"We are entering the period of increased transmission of this virus that can cause serious disease," Fielding said.

He said people should empty pools of stagnant water and use an insect repellent containing the strong chemical compound DEET, especially at dawn and dusk in mosquito-prone areas.

Mosquitoes get the virus by biting birds that are carrying West Nile Virus. Birds cannot transmit the virus to humans.

The virus had been found in 89 mosquito pools and 93 dead birds in the county as of  July 19, 2013. Three-quarters of the infected birds -- and nearly a third of the mosquito pools -- were in the South Bay.

"The wide-ranging distribution of our first human cases demonstrates that the virus can affect any location," the Department of Public Health cautioned.

Most people infected with the virus do not become sick or have only mild symptoms including fever, headache, nausea, body aches, and a mild skin rash. If they do appear, symptoms usually occur within three to 12 days after infection. The elderly and those with weakened immune systems are most at risk for developing severe symptoms, the department said.

Dead birds may be reported by calling 877-968-2473 or at the department's website. Stagnant swimming pools or "green pools" should be reported to the Public Health Environmental Health Bureau at 626-430-5200, or by calling a local vector control agency.

More information on West Nile Virus is available at 800-975-4448 or on the state's website.

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