When you enter Wilcox Farms' egg-production facility in Central Washington, you might think you've arrived at a sterile, classified defense laboratory.

Signs on the approach road warn that unless invited, you must turn back from the "biosecurity control area," about seven miles outside Moses Lake. Just inside the building, you must don a white paper suit, blue booties and a hairnet before entering the plant through a door with a combination lock. Employees must wear clean uniforms daily and hairnets.

"Our livelihoods depend on all of us working together to make sure we don't get a disease here," said Curt Nelson, senior production manager for Wilcox Farms' egg and dairy operations in Washington and Oregon.

Public-health experts have a more chilling warning, which King County Board of Health members will hear today: The avian influenza virus that has caused destruction of more than 120 million chickens and killed 50 humans in Asia since late 2003 is just a genetic tweak away from becoming one of the deadliest human epidemics in nearly a century.

The chicken flu virus, called H5N1, doesn't appear in its present form to pass easily from human to human. But experts say it could infect a human, genetically mix with a human flu virus and produce a highly infectious bug that could spread across the world in weeks.

Or the chicken virus could infect a pig, which also can carry a human flu virus, and the genetic mixing could occur there. Farmers could then spread the new virus.

"I think pandemic flu is the most serious, global, large-scale threat facing us. It's the one that keeps me awake at night, based on how fast it could spread and the fact we have no vaccine on hand," said Alonzo Plough, director of Public Health — Seattle & King County.

Thousands of Americans regularly travel abroad, but international coordination of preparations for epidemic control are slow in coming, said Dr. Ann Marie Kimball, a University of Washington expert on global diseases.

Today, Plough and other health officials will brief the county health board on local preparations for pandemic flu. He echoes the concerns of health officials worldwide, including the federal Centers for Disease Control and Prevention (CDC) and the World Health Organization.

In King County, Plough says, as many as 1.2 million of the county's 1.75 million people could be infected. In the first two weeks, nearly 2,000 could die. And up to 600,000 people could become quite ill, including 5,000 hospitalizations in the three months or more before a vaccine could be manufactured.

Nationwide, the CDC predicts that in a "medium level" epidemic, as many as 100 million of the nation's 296 million people could be infected and 200,000 could die.

Around the globe, World Health Organization officials have variously estimated from 7 million to 100 million of the world's 6.4 billion people could die, but they say it is impossible to predict accurately.

County and state officials have an established early warning system for the deadly virus. Primary-care physicians are the primary sentinels.

Through repeated newsletters, they have been asked to report patients with flu symptoms who have recently traveled to countries where outbreaks of the disease have been reported: Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand and Vietnam.

Public Health also monitors emergency-room visits, and hospital staffs are asked to report pneumonia cases in recent travelers to the outbreak countries. Hospitals also are on the lookout for clusters of respiratory illnesses in their workers.

Last month, Plough and Dr. Jeff Duchin, Public Health's director of communicable-disease control, met with officials of all 19 hospitals in King County, large group medical practices and representatives of medical specialty organizations. This week, they met with officials of suburban cities.

The message to all: Think about and plan what you would do if large numbers of employees were out sick. How would essential services such as police, firefighting, emergency medical care and garbage collection be provided? What would be the impact of Public Health orders to close schools and ban large public gatherings such as sporting events and concerts?

Hospitals and health authorities must consider 5,000 patients needing treatment, when only 5,300 beds are licensed. Cancellation of elective surgeries, early discharges and use of other facilities for treatment are possibilities, said Cassie Sauer of the Washington State Hospital Association.

"It would be business as un-usual," Plough said.

Chicken-farm concerns

Disease experts say they think a human epidemic likely would be brought to this country by humans — rather than the H5N1 avian virus being brought in by animals, then mutating to a human form.

But on chicken farms, there is plenty of worry that somehow a virus in the H5N1 family or another virus family could enter the facility. A year ago, more than 17 million chickens were destroyed as a flu virus swept through British Columbia's Fraser Valley, not far from the U.S. border. It was not H5N1, but about 12 poultry workers had mild flu-like symptoms during the outbreak, which some think may have started from an infected wild bird.

At Wilcox Farms, Curt Nelson and James Sauter, general manager in Moses Lake, figure that the company would lose at least $8 million if a virus destroyed the 600,000 chickens and egg inventory there. They worry, too, about their plants in Roy, Pierce County, and Aurora, Ore., which also contribute to the 5.4 million eggs a week the company sells.

Biosecurity at the plants is paramount. Besides wearing sanitized clothing, employees are forbidden to have contact with any outside birds. They can't own a bird, be around birds at a friend's house or the zoo, or attend any events involving birds.

At the Moses Lake plant, truck drivers are allowed only in the office, separate from the five sprawling henhouses and egg-processing rooms.

Inside the henhouses, air flow is directed from the roof downward, manure is removed daily to keep down flies, and rodent traps are abundant. Each henhouse is disinfected when it receives a new flock every 110 weeks to replace birds that are no longer productive and are used for meat products. The henhouses are separated by long, covered halls.

"By the time it [a virus] got in here, it would be too late" to do much about it, said Nelson, standing inside one of the long henhouses. "That's why we so limit access."

Animal-health authorities say a bird flu virus is more likely to infect a small farm that doesn't take such precautions. That's why state officials are beginning a surveillance programs to catch it as early as possible.

State veterinarian Leonard Eldridge plans a program to regularly collect sample eggs from small farms and farmers' markets to test them for flu antibodies.

The Washington State University poultry lab in Puyallup, which will do the testing, will partially identify any antibodies found, and virulent types will be sent on to the National Veterinary Services Laboratory in Ames, Iowa, for specific typing. Within hours of the initial identification, lab workers can test blood and throat swabs from chickens on the suspect farm, said Dr. Singh Dillon, director of the Puyallup lab.

Eldridge said he hopes the program also may be able to provide inspectors at bird shows. "The last thing we want to say is: 'We should have done this or we should have done that after a big [outbreak],' " said Eldridge. "We want to catch it early, get around it and stop it."

Importation ban

Health officials are not very concerned that the H5N1 virus could spread from Asia to the U.S. by migratory birds, which have spread the disease abroad. Seasonal migration patterns are north-south, rather than east-west. But they do worry the virus could come in through the importation of birds.

The CDC has banned the importation of all birds from affected countries. But animals are sometimes smuggled. Two years ago, for example, millions of chickens had to be destroyed in California, Arizona and Texas after another bird virus, Exotic Newcastle Disease, was spread by chickens believed to have been smuggled from unknown locations for illegal cock fighting.

Health authorities also worry about the legal importation of exotic pets. Two years ago, more than 50 people contracted monkey pox, which causes a flu-like illness, after the virus spread in a pet store from an imported Gambian rat to prairie dogs to pet owners.

No one knows yet the range of animals that can carry the H5N1 virus. CDC authorities cite recent research suggesting that cats can carry and transmit the virus and that pigs can carry a genetically related virus.

"The host range of this virus we don't really know yet," said Dr. Mira Leslie, the state Department of Health's public-health veterinarian.

Warren King: 206-464-2247 or wking@seattletimes.com