CONCORD, Calif. --The Contra Costa Mosquito and Vector Control District confirmed Friday four groups of mosquitoes, five dead birds and two chickens have tested positive for West Nile Virus in recent weeks.
Officials with the district said the mosquitoes were trapped in Discovery Bay last week and earlier this week, the birds were found in Antioch, Brentwood, Concord and Danville and the chickens were located in Holland Tract and Oakley.
Inspectors fogged for adult mosquitoes in Discovery Bay on Monday.
This year, the district has reported finding West Nile Virus in seven groups of mosquitoes, six chickens and 19 dead birds.
The district is warning people the two species of mosquitoes in the county capable of transmitting the virus prefer to feed on birds, but people can become infected when a mosquito bites an infected bird and then a person.
The symptoms of the mild form of West Nile virus include fever, headache, tiredness, body aches and swollen lymph glands and can last from a few days to weeks, according to the district. The virus can also be fatal.
The district is asking residence to reduce the risk of contracting mosquito-born diseases by dumping or draining standing water, using repellents that contain DEET, Picaridin or Oil of Lemon Eucalyptus and to avoid being outdoors when mosquitoes are present.
The district is also asking residents to report neglected swimming pools by calling (925) 771-6195 and to report dead birds to the state hotline at 1-877-968-2473.
Since 2005, 47 people in Contra Costa County have been diagnosed with West Nile Virus, and two people died from the disease in 2006, according to the district.