At least one person who tested positive was from the South Bay, according to Los Angeles County Department of Public Health spokesman Allen Solomon.
Previously, more than a dozen dead American crows infected with West Nile virus were found in the Palos Verdes area, including in the cities of Rancho Palos Verdes, Palos Verdes Estates and Rolling Hills Estates, according to recent statistics from the West Vector Control District.
Two people who tested positive for West Nile virus were hospitalized but are recovering. The other three were blood donors who never became ill, according to the county.
Donated blood is regularly screened for West Nile virus.
"We are entering the period of increased transmission of this virus that can cause serious disease," according to Dr. Jonathan Fielding, the county's director of public health. "Taking a few simple precautions can greatly reduce the risk of mosquito bites, the primary pathway to human infection.
"West Nile can appear anywhere in Los Angeles County, or around the state, and we are urging people to take precautions, such as getting rid of pools of stagnant water around their homes and using a repellent containing DEET when outdoors in mosquito-prone areas, especially around dawn or dusk."
In 2012, there were 174 human cases of West Nile virus in Los Angeles County, the second-highest since 2004, according to the county.
West Nile virus is passed to human beings through the bite of an infected mosquito, which typically obtains the disease by feeding on infected birds.
According to the Centers for Disease Control and Prevention, less than one in 150 people who are bitten by an infected mosquito become severely sick. But in those rare cases, the virus can cause encephalitis or even death.
Health officials said about 20 percent of people infected with the virus will experience symptoms such as fever, headaches, nausea, swollen lymph glands or a skin rash.
Health officials recommend that to avoid the disease, residents should:
- Avoid outdoor activities around dusk and dawn when mosquitoes are most active.
- Wear long-sleeve shirts and pants when outdoors.
- Apply insect repellents containing active ingredients such as DEET, Picaridin or oil of lemon eucalyptus.
- Keep tight-fitting screens on doors and windows to keep mosquitoes out.
- Eliminate all sources of standing water around their homes and properly maintain ornamental ponds, pools and spas.
—City News Service, with additional reporting by editor Nicole Mooradian.
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