Two dead crows, one from King County and another from Thurston County, Washington, have been found infected with the West Nile Virus. 

The death of the crows and the warm weather, which is propitious for mosquitoes, indicate that humans remain at risk of the virus this fall.

WNV has been active in Eastern and Central Washington, and a human case of the infection was confirmed a month ago. Two other persons have been exposed while passing through Eastern Washington and Oregon. Consequently, they are considered possible victims.

In 2008, nine birds and over a dozen horses have tested positive for the virus. Nearly all the animals were from Eastern Washington. In addition to these cases, WNV has been detected in no less than 40 mosquito pools. The West Nile virus can be spread through insects’ biting or blood transfusion.

"These latest positive birds confirm that West Nile virus has spread to both sides of our state," according to Jude Van Buren, an epidemiologist with the Washington State Department of Health. "While the fall weather is getting cooler, mosquitoes are still out there, and people should take precautions to avoid getting bitten."

According to Dr. Diana Yu, health officer for Thurston and Lewis counties, people can avoid contracting the virus by wearing trousers and long-sleeved shirts while outside, staying away from mosquito-infested areas, or using repellent when the contact with the insects s is inevitable. Besides, they should repair damaged window screens and doors and avoid getting out between dusk and dawn, when the transmitters of the virus are ready to attack.