Barbara Houghton


El Dorado County Environmental Management and Health Services Departments received confirmation on June 13, 2012 that West Nile virus has been detected in two birds found in the South Lake Tahoe area; the first confirmed positive results for 2012.  The birds, two American Robins, were found on June 6, 2012 in the Tahoe Keys area of South Lake Tahoe.  There have been no human cases of West Nile virus reported in El Dorado County for 2012.  

“Confirmation of West Nile virus positive birds means the virus is circulating in the community and there is a heightened risk of infection in humans,” said Dr. Robert Hartmann, Interim El Dorado County Health Officer. “It appears that West Nile season has arrived early this year.  Residents are urged to take 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 which 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.

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

Vector technicians are setting additional traps, and locating and treating mosquito larval sources.  If needed, ground spraying may occur in affected areas to reduce adult mosquitoes.  These efforts are part of ongoing vector control efforts and the public is encouraged to assist by reporting and removing sources of standing water is their yards.

To reduce the risk of being bitten by mosquitoes, the following is recommended:

  • Drain standing water around property and keep water in swimming pools, ponds and troughs circulating or treated with “Mosquito Dunks”.
  • Apply insect repellent containing DEET or another approved substance (e.g. picaridin, oil of lemon eucalyptus or IR 3535) on exposed skin when outdoors among mosquitoes.
  • 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  Wear gloves and place dead birds or squirrels in a double plastic bag if disposing of them yourself.

Mosquito problems and neglected swimming pools should be reported 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 or

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