West Nile virus detected in chickens near Knightsen

Contra Costa County residents are being warned about the threat of West Nile virus after seven chickens tested positive on Holland Tract near the town of Knightsen.

Contra Costa Mosquito & Vector Control District officials urge residents to use precautions to prevent mosquito bites and guard against the virus as hot weather speeds mosquito development and virus growth.

"Warm weather is conducive to virus transmission, and we have seen moderate levels of West Nile virus activity in warmer areas of our neighboring counties in the Central Valley and Delta over the past few weeks, so it is not surprising that we're now starting to detect the virus here as well," Steve Schutz, the district's scientific programs manager, said in a statement. 

The positive tests came from the district's flocks of chickens. When a chicken is bitten and infected by a mosquito, it develops antibodies to fight off the virus. 

Samples that test positive for antibodies indicate virus activity in specific areas of the county and help the district determine locations for prevention and control efforts.

"We usually detect the virus in dead bird samples first, but so far this year we have been receiving relatively few dead bird reports from the public," Schutz said. 

Residents who find a dead bird can report it by calling (877) 968-2473 or by going to the statewide West Nile Virus Hotline at http://westnile.ca.gov/report--wnv.php.

Residents can reduce their risk of contracting West Nile virus and other mosquito-borne diseases by dumping or draining standing water; using repellents containing DEET, Picaridin or Oil of Lemon Eucalyptus; and avoiding the outdoors when mosquitoes are present, typically at dawn and dusk. 

For more information on identifying and preventing West Nile virus, contact the Mosquito & Vector Control District at www.contracostamosquito.com.