The El Dorado County Environmental Management and Health Services departments received confirmation Sept. 1 that a bird found in the South Lake Tahoe area tested positive for West Nile virus, the first for 2010.

The bird, a Western Scrub-Jay, was found Aug. 24. A second positive bird, a Swainson’s hawk, was also reported for El Dorado County on Wednesday; however, it is believed that the bird was brought into El Dorado County from Mono County.

So far this year, West Nile virus activity has been reported in 30 California counties, including neighboring Sacramento and Placer counties. There have been 34 human cases and 11 horse cases of West Nile virus reported in California in 2010.

“Confirmation of our first West Nile virus positive birds means the virus is circulating between birds and mosquitoes and there is a heightened risk of infection in humans,” Virginia Huber, Tahoe division manager of the Environmental Management Department, said in a statement. “Residents are urged to take extra precautions to protect themselves from mosquito bites.”

West Nile virus is transmitted to humans through the bite of an infected mosquito. Mosquitoes pick up the virus when they feed on infected birds. The illness is not spread from person-to-person. Most people infected with West Nile virus show no symptoms. However, some people may experience high fever, severe headache, tiredness and/or a stiff neck that may last several days to several weeks. The most serious cases of West Nile virus infection can lead to encephalitis, an inflammation of the brain, which can be fatal. Long-term neurological problems have also been seen in some survivors of severe West Nile virus infection.

Mosquito surveillance programs are in place throughout the county. Programs include trapping and testing mosquitoes, reporting neglected swimming pools, and reporting and testing dead birds and tree squirrels. In addition, the Health Services Department has instituted human surveillance activities, and physicians are encouraged to routinely test human cases of viral meningitis and encephalitis for West Nile virus.

To reduce the risk of being bitten by mosquitoes, Huber recommends:

• Eliminate mosquito breeding sources by draining all standing water around property. Keep water in swimming pools, ponds and water troughs circulating or treated with “Mosquito Dunks” or mosquito fish.

• Apply insect repellent that contains DEET or another approved substance (e.g. picaridin, oil of lemon eucalyptus or IR 3535) on exposed skin when outdoors (always read and follow label instructions).

• Mosquitoes are most active at dusk and dawn. While outside among mosquitoes, dress in long sleeves and long pants.

• Make sure doors and windows have tight fitting screens, kept in good condition.

• Report dead birds and tree squirrels to the State West Nile Virus hotline at (877) WNV-BIRD (877-968-2473) or online at www.westnile.ca.gov. Wear gloves and place dead birds or squirrels in a double plastic bag if disposing of them yourself.

Report mosquito problems and/or neglected swimming pools to the El Dorado County Environmental Management Department at (530) 621.5300 in Placerville or (530) 573.3450 in South Lake Tahoe. Additional West Nile virus information is available at www.westnile.ca.gov or www.edcgov.us/emd.