West Nile virus infects two in Placer County

They are the second and third cases here this year
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Two residents, from Roseville and Lincoln, have become ill from West Nile virus and are recovering at home, Placer County health officials announced Monday. These are the latest cases since August, when a Roseville resident became the first in the county to be diagnosed with the virus in 2010.

In 2009, there were no human cases reported in Placer County, while in 2008, there were six, according to a release.

“Even though summer is winding down, mosquitoes are still active and human infections with West Nile
virus are not unusual at this time of year,” said Dr. Mark Starr, Placer County Director of Community
Health and Clinics, in the statement.

California has reported 45 human cases of the virus in 34 counties, including one fatality in Fresno County, the release said. Positive dead birds have been found in 25 counties and nine counties have had horses diagnosed with the disease.

About 20 percent of those infected may experience mild to moderate flu-like symptoms, called West Nile fever, while one in 150 people will become very ill, the county said. People over 50 or with suppressed or compromised immune systems are more likely to become seriously ill.

The county reminded residents:

  • Drain standing water weekly, since that's where mosquitoes lay eggs. Check your yard for water in old tires, flowerpots and bird baths.
  • Avoid mosquito bites by staying indoors at dusk and dawn when mosquitoes are most active, and assure that your window screens are in good condition.
  • If you must be outdoors when mosquitoes are active, wear long sleeves and long pants, and use an insect repellant that contains DEET, picaridin or oil of lemon eucalyptus.
  • If you know of swimming pools that are not maintained and become “neglected” report them to the District at (916) 380-5444. Or at, you can request an inspection of a property.
  • As dead birds are a surveillance tool to help track West Nile virus, you are encouraged to report them by calling the California WNV hotline at 1-877-WNV-BIRD (1-877-968-2473), or at
  • Horses are vulnerable to West Nile virus, and the mortality rate for unvaccinated horses is very high. Contact your veterinarian about protective immunizations. West Nile does not spread between humans and horses.

For questions about West Nile virus can call Placer County Community Health at (530) 889-7141, or visit

~ Staff report