LAKEPORT, Calif. - After a summer nearly free of signs of the West Nile Virus, the virus is making a late appearance in Lake County, according to county health and vector control officials.

Routine surveillance through mosquito testing showed the first positive evidence of West Nile Virus in samples collected in early through mid-September in locations near Kelseyville and east of Middletown.

An American crow in the Clearlake Oaks area on Sept. 15 has also tested positive for West Nile Virus.

Although approaching fall weather is associated with diminishing numbers of mosquitoes, Jamesina J. Scott, Ph.D., the District Manager and Research Director of the Lake County Vector Control District notes that “we are still seeing signs of mosquitoes capable of transmitting West Nile Virus.”

No human cases of West Nile Virus have been reported in Lake County this year, according to the Wednesday report.

Statewide, a total of 70 human cases have been reported from eighteen counties during 2011.

“Even though the West Nile season will soon be winding down, it is important to take precautions to avoid mosquito bites as long as there is any evidence that transmission of the infection is possible,” said Lake County Health Officer Dr. Karen Tait.

West Nile virus is transmitted by mosquitoes to a variety of animals and to humans. Mosquito and Vector Control agencies usually detect the virus in mosquitoes, birds and sometimes tree squirrels before human cases appear.

Most people who become infected with West Nile virus do not show symptoms and will recover uneventfully. Up to 20 percent of people will develop fever, headache, and other nonspecific symptoms that may last several weeks, health officials said.

Approximately one in 150 people will develop severe illness known as neuroinvasive disease. Health officials said people over age 50 and diabetics appear to be at most risk for the more severe forms of disease. There is no vaccine for humans.

Lake County residents are advised to avoid being outside when mosquitoes are active, especially near dusk and dawn; wear long sleeves and pants and use a mosquito repellent – always read and follow label directions – if they are outside when mosquitoes are active; and dump out buckets, wading pools and other sources of water where mosquitoes develop.

Call the Lake County Vector Control District at 707-263-4770 or visit the district's Web site at www.lcvcd.org to request assistance in addressing problems with mosquitoes.

To report a dead bird or squirrel, call 1-877-WNV-BIRD (1-877-968-2473) or visit the California Department of Public Health’s West Nile virus Web site at www.westnile.ca.gov.

For additional information on West Nile virus, visit http://www.westnile.ca.gov, http://www.cdc.gov/ncidod/dvbid/westnile/wnv_factsheet.htm and http://www.cdc.gov/ncidod/dvbid/westnile/RepellentUpdates.htm.

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