Two people in Placer County have tested positive for the West Nile virus (WNV) marking the first reported human cases in the county in 2008. The county residents are from Loomis and Roseville. Both had West Nile fever and are recovering well.
In 2008, WNV was first detected in Placer County in mid-July when dead birds tested positive for the virus. Detection of WNV in mosquitoes, which transmit the virus, occurred shortly thereafter. Statewide, 39 of 58 counties have detected the presence of WNV this year. WNV arrived in the United States in 1999 on the East Coast and then spread west, arriving in Northern California in 2004.
“In Placer County, we typically see the first human West Nile case in late summer,” said Dr. Mark Starr, Placer County Director of Community Health and Clinics. “Because West Nile infections are preventable, we strongly urge residents and visitors alike to take some simple precautions to avoid mosquito bites that can transmit the disease. Most people who are infected with West Nile virus will not become ill. However, for certain populations, the disease can cause serious illness and death.”
About 20 percent of those infected with WNV may experience mild to moderate flu-like symptoms, called West Nile fever, which may be prolonged. About one in 150 people will become very ill. People over 50 and people with suppressed or compromised immune systems are more likely to become seriously ill. West Nile virus is rare, but people with symptoms, including high fever, severe headache and stiff neck, should contact their health care provider immediately. In Placer County in 2007, there were four human cases of the virus; there were eight human cases in 2006.
The Placer Mosquito and Vector Control District and Placer County Health and Human Services offer the following reminders and information about preventing the spread of West Nile virus:
- 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, wearing long sleeves and long pants, and using 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) 435-2140. These pools are ideal breeding grounds for mosquitoes.
- Concerned residents may also request an inspection of a property or report a dead bird online through the District’s website: http://www.placermosquito.org or by calling the District at (916) 435-2140.
- 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 online at www.westnile.ca.gov.
- 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.
If residents of Placer County have questions about West Nile virus or mosquitoes, are having mosquito problems, or need mosquito fish, they should call the Placer Mosquito and Vector Control District at 916-435-2140 or visit the District’s website at www.placermosquito.org .