WASHINGTON -- Even as they sought to reassure a wary public, federal health officials detailed plans Wednesday to restrict the number of labs that can handle deadly flu viruses like the ones sent to thousands of facilities worldwide.
"We are working on the side of caution," said Dr. Julie Gerberding, director of the Centers for Disease Control and Prevention.
Labs around the world tracked and destroyed samples of the deadly flu strain, which has been included in a kit designed to test a lab's ability to identify viruses. The CDC was trying to determine why the deadly H2N2 flu virus was included in the first place.
"We are very concerned that this particular strain of virus was used for proficiency testing," Gerberding said.
Gerberding repeatedly described the risk of somebody contracting the virus as minimal. "If an unusual virus had emerged, we would have known it by now," she said.
Still, she said, the agency was intent on ensuring that every sample shipped to more than 4,000 labs in 18 countries or territories had been destroyed. So far, about 1,000 labs have sent statements to the College of American Pathologists confirming the samples they received were destroyed.
The World Health Organization's influenza chief, Klaus Stohr, said he was "relatively confident" most of the samples outside the United States would be destroyed by Friday.
Canada, South Korea, Hong Kong and Singapore have destroyed their samples, while Japan was doing the same, WHO said. Taiwan and Germany announced that they had destroyed all their vials.
The germ, the 1957 H2N2 "Asian flu" strain, killed between 1 million and 4 million people. It has not been included in flu vaccines since 1968; anyone born after that date has little or no immunity to it.
The samples were sent, beginning in September, as part of a testing process that measures a laboratory's proficiency in detecting various strains of influenza. The College of American Pathologists directs the testing and contracted with Meridian Bioscience, a company based in Cincinnati, to distribute the test kits.
A Canadian lab alerted WHO last month that the kit included the 1957 strain.
Gerberding said it was not clear why such a dangerous strain of influenza was included in the test kits.
"It's impossible to believe they did not know they were dealing with H2N2," Gerberding said.
The College of American Pathologists said Wednesday it was the association's policy not to have the kits include micro-organisms harmful to people.
Dr. Jared Schwartz, an officer with the organization, said Meridian thought it had sent an ordinary flu strain. He said Meridian found the virus in a "germ library" in 2000 that had come from another company.
Gerberding said the CDC would move quickly to update guidelines for how influenza strains are tested. That would mean limiting the handling of dangerous flu strains to labs that have extra protections in place for workers.
Gerberding said CDC and the National Institutes of Health had recommended that deadly flu viruses be handled by level 3 labs, which require special hoods and clothing to ensure that workers do not inhale a specimen. Currently, the strain can be handled by level 2 facilities, which do not require as stringent precautions.
Congressional action is also possible.
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."
Added Sen. Ted Kennedy of Massachusetts, the top Democrat on the Senate Health, Education, Labor and Pensions Committee: "Hopefully, it is a loud wake-up call for action by Congress and the administration to expedite the urgently needed investments in hospitals and all our other public health defenses, before this alarming series of errors becomes a massive national tragedy."
White House press secretary Scott McClellan said action to prevent a recurrence was ""a high priority for our government."
"What we're asking is that if anybody sees any suspicious illness that it be reported immediately," he said.
Labs in Canada, Brazil, France, Germany, Japan, Belgium, Bermuda, Chile, Hong Kong, Israel, Italy, Lebanon, Mexico, South Korea, Saudi Arabia, Singapore and Taiwan also received the kits.
Mike Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said he agreed that in general, the prospects for an outbreak were slight.
"All it takes is one lab accident where somebody becomes infected and it's a whole different ball game," Osterholm said.
He said the government should find out how the H2N2 samples so easily were distributed and how best to prepare for the potential spread of deadly infectious diseases.
"We can't have this happen," he said. "Who needs terrorists or mother nature, when through our own stupidity, we do things like this?"
AP medical writers Emma Ross and Marilynn Marchione and science writer Malcolm Ritter contributed to this report.
On the Net:
World Health Organization statement: http://www.who.int/csr/disease/influenza... core)04( underscore)12/en/
Meridian Bioscience: http://www.meridianbioscience.com