On Aug. 5, the Santa Clara County Department of Environmental Health Vector Control District confirmed that a dead Cooper's hawk discovered near the corner of Lincoln and Pine avenues was infected with the disease. The discovery brings to six the number of infected birds found in Santa Clara County since an infected crow was discovered three weeks ago.

"It's alarming," said David Westendorf, who lives near the corner where the bird was found. "We have two daughters here, and now I have to reinforce to them that if they see a dead bird or rodent on the street to stay away."

The bird by itself, however, isn't much of a danger to humans, said Kriss Costa, community resource specialist with Santa Clara County Department of Environmental Health Vector Control District. There's no evidence that the virus can be transmitted to people who take precautions when handling the dead bird.

Although there have been a very small number of cases in which the disease was spread through blood transfusions and organ transplants and during breast-feeding and pregnancy from mother to baby, mosquitoes are the primary means of transmission to humans.

When a mosquito feeds on a sick bird, it will become infected with the virus and can then pass it on to animals like horses, humans and other birds.

"It's the mosquitoes we have to worry about," Costa said. "People have to remember that the birds aren't the problem; they're victims, too. But when an infected bird shows up, it's a good indication to us that the mosquitoes are soon to follow."

Costa said that the bird was most likely a migratory bird that came from down south and died here. At press time, there have been no recorded cases in Santa Clara County of a mosquito carrying West Nile virus.

Although the disease is often fatal for certain types of birds, only about 20 percent of the people who are infected with the virus will get West Nile fever. Symptoms include fever, headache, tiredness and body aches. On some occasions, people may develop skin rashes or swollen lymph glands.

Of those who do develop symptoms, less than 1 percent get the severe form of the fever, which can be fatal, Costa said. So-called West Nile encephalitis or meningitis can include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

The Centers for Disease Control and Prevention website says people who are more than 50 years old are most at risk for becoming infected, so they should take special care to avoid mosquito bites.

The news of the bird's discovery has drawn mixed reactions from those who live closest to the location where the hawk was found.

Some, like Westendorf, are alarmed. Judy Guerra-Moran, however, who also lives near the intersection, said she's only cautiously worried.

"I'm somewhat concerned," she said. "I know the information that's come out saying that we need to watch out for stagnant water and open windows, so we just have to do what we have to do."

Al Koblinksi, another resident in the area, sees things a bit differently.

"There's nothing to worry about," Koblinski said. "I haven't had a mosquito bite in the 14 years I've been here, and everything bites me."

He said he doesn't foresee many infections in San Jose because there aren't many places for mosquitoes to live in the area.

But even if there were, the risk of people getting seriously ill from the disease isn't high.

Costa said that about 80 percent of people infected with the virus will see no signs at all that they have it. Even so, she and other county officials are urging people to exercise caution, as at least for some individuals, the disease can be fatal.

The vector control district recommends eliminating all sources of standing water that can support mosquito breeding and avoiding spending time outside during dawn and dusk when mosquitoes are most active. The group also advises wearing insect repellant and making sure doors and windows are shut at night.

Officials are also urging the public to report dead birds that show no obvious signs of trauma to the Santa Clara County Vector Control District. Costa warned, however, that vector control may be too busy to come immediately.

"We get 40 to 50 such calls a day," she said. "We want to come, but many times we cannot."

Moreover, not all birds are prone to getting sick from the disease, so they are not on vector control's watch list. For example, there have been no reported West Nile virus cases involving pigeons, chickens and ducks, so if someone comes across any of those birds that are dead, the birds most likely didn't die as a result of West Nile virus, Costa said.

Other birds are very susceptible to the disease, so officials are highly interested in learning about any of them found dead.

"We're expecting the local crow and raven population in the area to be decimated," Costa said. "That's what we've seen happen in other areas where the virus has hit."

Magpies, jays, sparrows and finches are also susceptible to the disease, as are birds of prey like hawks, falcons, eagles and owls.

Costa said that in the event officials don't come within 48 hours of a bird's death, the reporting person should throw away the bird in a plastic bag, being careful not to touch the bird with bare skin.

Domestic animals like dogs and cats are not at risk. She said there have been several cases, most notably in New York, where feral cats and dogs have tested positive for the virus, but none showed any symptoms.

And as far as she knows, in the United States only one infected dog, a dachshund in Nevada, is in danger of dying from the disease.

"And," she said, "it's a very old dog."

Horses are another matter. Like many birds, when horses get infected, they often get very ill or even die. A vaccine is available for horses. There is also a vaccine available for exotic birds.

There is no West Nile virus vaccine available for humans.

One is in development, but, Costa said, it's not expected to be available for at least another two years.

If residents find a dead bird on their property or in their neighborhood Monday through Friday, before 3 p.m., they should contact the California Department of Health Services at 1.877.WNV.BIRD or the Santa Clara County Vector Control District at 408.792.5010. Residents may also submit the information through the California state website at westnile.ca.gov/deadbird.cfm. For more information, call the Santa Clara County Vector Control District at 408.792.5010.