West Nile Virus: Mosquitoes Test Positive In Contra Costa County

CONTRA COSTA COUNTY, CA — A group of mosquitoes has tested positive for West Nile Virus in Contra Costa County, the Contra Costa County Mosquito and Vector Control District said Friday.

The mosquitoes were collected from a trap in the city of Oakley and marked the first group of mosquitoes to test positive for WNV so far this year in the county.

Certain species of birds may carry WNV. Once a mosquito bites an infected bird, the mosquito can become infected with the ability to transmit WNV to another animal or a person through a single mosquito bite.

Since 2005, 75 people in Contra Costa County have been diagnosed with West Nile virus. In 2006, two people in the county died from the disease.

"It is important that Contra Costa County residents take precautions to avoid mosquito bites by using an effective insect repellent when outdoors, especially at dawn and dusk," said Steve Schutz, scientific program manager for the District. "Wear long-sleeved shirts and pants to reduce the amount of exposed skin that can be bitten. And, if possible, avoid being outdoors where mosquitoes are present."

WNV can grow more efficiently when temperatures are consistently warmer than 55 degrees. The District advises County residents to take action to reduce the risk of WNV by avoiding mosquito bites.

Another way to reduce the risk of being bitten is to dump out any amount of standing water, county officials said, as mosquitoes develop from egg to biting adult in water. Even the small amount of water that can collect in a bottle cap can produce mosquitoes.

Also, make sure window and door screens do not have any rips or tears and that screens fit properly, officials said.

Contra Costa County residents can report dead birds by phone at 877-WNV-BIRD (968-2473) or online. County residents can also request mosquito service for residential property by calling 925-685-9301 or online.