A dead bird found in Danville over the weekend tested positive for West Nile virus, the Contra Costa Mosquito & Vector Control District confirmed Wednesday morning.
The western scrub jay was discovered near the intersection of Podva Road and San Ramon Valley Boulevard on Sunday, according to district officials.
It marked the third dead bird found in the San Ramon Valley to test positive for the virus this year, following a Steller's jay located at Roan and Clydesdale drives in Danville on July 23 and an American crow located at Dos Rios and Bollinger Canyon roads in San Ramon on Sept. 9, according to the district.
"To quote the late Yogi Berra, 'It ain't over till it's over,'" Steve Schutz, the district's scientific program manager, said referring to the mosquito season. "West Nile virus is still active, there is still a risk of contracting it from mosquitoes, and we all still need to take the necessary precautions to control mosquitoes and their bites."
Countywide, there have been nine birds, six groups of mosquitoes, 16 chickens and one Brentwood horse reported as virus-positive this year. No human cases have been reported in Contra Costa County to date.
Birds are the reservoir for West Nile virus, which can be transmitted to humans via mosquitoes.
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, district officials said.
The district preaches prevention, encouraging people to wear mosquito repellents, avoid going outside at dawn or dusk when mosquitoes are often present, dump or drain standing water where mosquitoes could lay their eggs, and report dead birds and neglected swimming pools.
Most cases of the virus in humans are mild and include symptoms such as fever, headache, tiredness, body aches and swollen lymph glands, according to district officials. Severe cases of West Nile virus can be fatal.
The most recent Contra Costa County human fatalities from the virus occurred in 2006, when two people died, officials said.
According to the district, most West Nile virus cases are not diagnosed and are "grossly under-reported."
For more information, call the district at 771-6195 or visit its website.