Released Aug. 23, 2007

AUBURN UNIVERSITY, Ala. -- While it hasn’t exactly fizzled out, the specter of a worldwide avian flu outbreak no longer is perceived among some researchers as the threat it once was.

Researchers have identified a number of changes a flu virus would have to undergo to mutate into a human epidemic. But so far, they’ve detected only a few of these changes in the avian flu virus.

At Auburn University, Robert Norton, a professor specializing in veterinary bacteriology who works closely with the Alabama Cooperative Extension System to educate Alabamians about avian flu, is not surprised by the findings.

“That’s been my thinking all along,” Norton says.

“There are multiple steps that have to be taken in the virus to become a threat, many of which we don’t understand,” he says. “But I think people at least should take comfort in the new information, which indicates some distance between the current virus and a form that could affect humans.”

Scientists have identified 32 markers or clear differences between influenza viruses in birds and in those that affect humans.

So far, the researchers, made up of a team from St. Jude Children’s Research Hospital in Memphis, Tenn., have concluded that the current bird-flu viruses “are no more adapted to humans today than they were in the past.”

The team has compared the genetic makeup of thousands of avian flu viruses to thousands of viruses from human patients. They have found 32 amino acids that differentiated the two groups, according to an article posted August 22 in the Washington Times. These 32 are viewed as “markers on a road” toward a pandemic, says Mark Finkelstein, a research associate at St. Jude’s Hartwell Center, who led the research team.

Thirteen of these markers were present in flu viruses that caused deadly flu pandemics in 1918, 1957 and 1968. However, no single human infection of bird flu examined showed more than two of these markers, which means that the bird flu is probably “more than a couple of small steps away” from becoming a human pandemic.

“It doesn’t mean there is not a risk but as I’ve said all along, these types of things must be put in context,” Norton says. “We should continue to monitor, but we shouldn’t be excessively paranoid that every single outbreak of bird flu is a threat to our lives.”

Norton also believes it was a mistake for the nation’s health establishment to concentrate solely on avian flu as opposed to other sources of viruses that possibly could mutate into human forms.

“You don’t base everything on H5N1 (avian flu) vaccines. You don’t see pandemics coming only from birds.”

He says a far better approach would be to prepare for pandemics in general.

“You can make all the preparation for the H5N1 outbreak, but nature nevertheless could throw us curveball despite our best efforts.”

What kind of curveball could that turn out to be? Norton says a worldwide pandemic conceivably could be sparked from a swine virus or from “a virus that starts in humans and stays in humans.”

“It doesn’t come just from chickens,” Norton says. “We can focus solely on H5N1 and spend millions of dollars on this virus, but what if it’s another virus?”

There have been 321 cases of human infection with avian flu and 194 deaths since 2003, mostly in Asia, according to the World Health Organization. However, the flu has not spread as rapidly as the 1918 flu, which killed millions around the world.

Scientists around the world are striving to find out what accounts for this slow spread.

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Contact: Jim Langcuster, (334) 844-5686