Read the most current information about avian influenza and cumulative case numbers

A bird-flu pandemic likely will reach U.S. shores in the next decade, Dr. Kristy Bradley, deputy state epidemiologist for the Oklahoma State Department of Health, said Tuesday.

"Prior to the last decade or so, the thought was the influenza from birds would be mild or just cause conjunctivitis in humans," she said at the second annual Prevention Conference, being held through Wednesday at the Tulsa Marriott Southern Hills hotel, 1902 E. 71st St.

But "bells went off" in 1997 when 18 people in Hong Kong contracted bird flu and six died from it, Bradley said.

"Bird flu" refers to an influenza from a virus found chiefly in birds, but infections can occur in humans.

"We've been tracking H5N1 (a strain of bird flu) since 1997," Bradley said. "It has continued to spread to parts of Africa and the Middle East and continues to cause a lot of problems in Asia."

The questions are whether the U.S. should worry about a bird-flu pandemic and whether the nation is prepared to respond to a massive outbreak of the virus, she said.

"We do get a little more concerned about the H5N1 virus because it's not behaving like any other bird flu we've seen," Bradley said.

It has shown resistance to antiviral medications, and human-to-human transmission has been confirmed, she said.

"We always have that possibility we could have an imported case in our country," she said.

Depending on its severity, a U.S. bird-flu pandemic could mean that 43 million to 100 million people would be infected and an estimated 89,000 to 207,000 people would die, according to the U.S. Centers for Disease Control and Prevention.

Between 314,000 and 733,000 Americans would be hospitalized, again depending on the severity of the outbreak, Bradley said.

"Hospitals would be stretched to the max," she said.

The economic impact of a U.S. bird-flu pandemic is estimated at between $71 billion and $166 billion, Bradley said.

"That can seem pretty daunting," she said.

Both the federal government and Oklahoma health authorities have plans in place to respond to such a crisis, Bradley said.

Vaccines typically are the first line of defense for a flu outbreak, although authorities are limited to speculation about which strain of virus will prompt an epidemic.

The U.S. has begun stockpiling 40 million doses -- at two doses per person -- of prepandemic H5N1 bird flu vaccine. Oklahoma is set to receive 20,000 doses of the vaccine, Bradley said.

After five years, the medication loses its effectiveness, so the doses must be thrown out and new ones brought in, she said.

"This is the hedging and the risks you take, because you cannot predict how effective it will be," Bradley said.

State plans include prioritizing who will get the vaccine based on risk factors for complications, she said.

Any flu pandemic that hits the U.S. most likely would originate from a bird influenza, Bradley said.

"As you can see, it's very much up in the air," she said. "Nature generally has the upper hand."

Kim Archer 581-8315
kim.archer@tulsaworld.com