California and its Chickens On Lookout For
West Nile Virus

August 4, 2002
By ANDREW BRIDGES AP Science Writer

WEST COVINA, Calif. (AP) - California is counting on 2,000 chickens to provide early warning for when the potentially deadly West Nile virus reaches the state.

Under a state- and county-run program, chickens placed statewide have their blood regularly tested for antibodies that would indicate they were bitten by virus-carrying mosquitoes.

On a recent morning, Amanda Colombo, a 24-year-old summer employee of the San Gabriel Valley Mosquito and Vector Control District, took samples from six Rhode Island red hens.

Drawing them one by one from their coop, she gripped them between her legs unceremoniously but firmly, then pricked their combs with a needle.

So far, no trace of the virus has been found in California or other Western states but its arrival appears guaranteed.

"It's no longer if it's going to come, it's when," said Stan Husted, supervising public health biologist for the California Department of Health Services.

Since West Nile was first detected in New York in 1999, it has spread to 33 other states and the District of Columbia - virtually every state east of the Rocky Mountains, save Kansas and South Carolina. There have been nearly 200 confirmed human cases of the virus, including 22 deaths.

The virus is closely related to St. Louis encephalitis, which already is present in California. Both viruses typically cause flulike symptoms in humans, but can lead to deadly inflammation of the brain.

Chickens are immune to the virus, making them valuable sentinels. Other species, most notably crows, jays, magpies and ravens, die within two weeks of infection. During that period, they remain infectious for up to five days.

California officials ask residents to call a toll-free number - (877) WNV-BIRD - to report bodies of birds of those species that have been dead for less than a day. The bodies will be tested for the virus, supplementing the ongoing testing of both chickens and mosquitoes.

Some scientists believe migrating birds play a role in dispersing the virus but cannot be certain.

Husted said California's location along the Pacific flyway used by migratory birds may mean the virus will appear in the state before anywhere else in the West.

"It's not necessary for all of the states east of here to get West Nile before we get it here," Husted said.

The virus also could be dispersed by mosquito stowaways on trucks and airplanes or through the commercial transport of infected birds, said Nicholas Komar, a research biologist with the Centers for Disease Control in Fort Collins, Colo.

http://www.sacbee.com/state_wire/story/3848922p-4874268c.html