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U.S. Seeks Cause of Flu Virus Mix-Up

Destruction of dangerous pathogen continues; no reports of illness

THURSDAY, April 14, 2005 (HealthDay News) -- U.S. health officials were still trying to determine Thursday how a lethal flu virus had been mistakenly shipped to thousands of laboratories around the world.

Meanwhile, health officials in 18 countries continued to destroy the virus, which had fueled a 1957-58 pandemic that killed between 1 million and 4 million people worldwide, including 70,000 people in the United States.

Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention (CDC), said Wednesday that the risk of an outbreak was "very low," and there were no signs that anyone had been sickened by the virus. Still, she added, "We're not taking any chances, and we are doing everything we can to make sure there is no threat to human health."

The virus, H2N2, has not been included in flu vaccines since 1968. Anyone born after that date has virtually no immunity to the germ.

Gerberding said the CDC would work with pathologists and other health organizations to establish better guidelines for lab testing of germs like H2N2, the Associated Press reported.

U.S. lawmakers were also expressing concern about the mix-up.

Senate Majority Leader Bill Frist, R-Tenn., a heart-lung surgeon, said the shipments underscored "the need to bolster America's domestic and global public health infrastructure," the AP said.

Gerberding said at least 4,000 labs in 18 countries received the virus in quality-control test kits sent out by Meridian Bioscience Inc. of Cincinnati, which makes influenza test kits -- called panels -- for medical facilities.

Meridian probably knew that the H2N2 virus was in the panel but somehow didn't take into account that the virus could represent a public health threat, she said.

"We don't know why they included the virus, but it was probably not inadvertent," Gerberding said. "It was probably a situation where the advantage of using a strain that grows well and can be easily manipulated in the lab was the driving force without even considering that the test strain in a panel could cause a hazard."

Meridian executives were traveling and not available for comment, a company spokeswoman told the Associated Press on Thursday. On Wednesday, news reports quoted company spokesmen saying Meridian had followed regulations in sending out the samples.

By Thursday morning, Canada, South Korea, Hong Kong and Singapore had destroyed their samples, while Japan was doing the same, World Health Organization officials said, the Washington Post reported. Taiwan and Germany announced they had destroyed all their vials.

Test kits were also sent to labs in Belgium, Bermuda, Brazil, Chile, France, Israel, Italy, Lebanon, Mexico and Saudi Arabia.

Klaus Stohr, a WHO virologist and infectious disease expert, said he was "relatively confident" most of the samples outside the United States would be destroyed by Friday, the AP said.

In the United States, documentation showed that more than 1,000 samples have already been destroyed, according to a spokesman for the College of American Pathologists (CAP), which is monitoring the destruction process.

Most labs would automatically destroy the panels after they had finished using them, Dr. Jared Schwartz, the CAP spokesman, said.

Labs are being asked to report immediately to the CDC or the appropriate public health authority once the virus is destroyed, Gerberding said. But she also said Thursday that she did not know how many labs had already destroyed their specimens.

Although authorities were notified of the mistake only three weeks ago, the first specimens were actually mailed out in September 2004, according to Schwartz.

Nevertheless, he too believes the "risk to the general public is extremely low."

The virus has been kept in freezers for years and has been grown in tissue culture, which makes it less virulent, Schwartz said.

"What we're talking about here is a theoretical concern, which is legitimate," he said.

At a news conference Wednesday, Gerberding appeared to echo his caution.

"The strain has been passed in the lab many, many times, and our experience with viruses is that when they are used like this, they very often lose infectivity," she said. "We have no proof of that in this case, but that's what we've seen when other viruses go through the process."

"The specimens actually were sent out in September of 2004 and there's been no evidence of any outbreak or infection among laboratory workers," Schwartz added.

"The greatest potential threat theoretically would be to the individual lab workers who actually handled the specimen, and that threat is extraordinarily low," he said. "These people are trained. It's very rare to find a lab worker who has gotten an infection because they worked in a lab, period."

For the threat to reach the general public, the lab worker would have to get infected, develop the disease and go out into the world to spread it, he said.

The problem first surfaced, according to WHO, when a Canadian testing lab detected the deadly virus. Canadian health officials notified WHO authorities on March 26, and the CAP was notified April 8.

How did Meridian come into possession of such a deadly germ?

According to the AP, Meridian took a sample from the pathology college's stockpile and selected the 1957 virus. Schwartz said the pathology college had received the strain from a "germ library" in 2000.

It's not entirely clear how the mistake happened, Schwartz said, but the virus strain was classified as a Biologic Safety (BS) level 2, meaning it could go to any laboratory performing general laboratory work.

"It was their belief that the virus that they put into our packets that were sent to our customers was a relatively innocuous virus," Schwartz said.

What the lab didn't know -- and what the CAP later found out -- was that the CDC was considering upgrading the strain to a BS level 3, Schwartz added.

Dr. Nancy Cox, head of the CDC's influenza division, confirmed that the agency has drafted recommendations to upgrade this particular virus to level 3.

The organisms that were accidentally distributed to the labs around the world are used widely in research, which could include developing potential new vaccines or anti-viral drugs, Schwartz explained. They are also used in quality control or to verify if a new test actually works.

"There are lots and lots of these organisms, and they are predominantly used in research," Schwartz added.

More information

The World Health Organization has the latest information on the deadly virus.

SOURCES: Julie Gerberding, M.D., director, U.S. Centers for Disease Control and Prevention, Atlanta; Jared Schwartz, M.D., spokesman, College of American Pathologists, Northfield, Ill.; April 12, 2005, World Health Organization statement; Associated Press; Washington Post
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