At least four countries and more than 1,500 U.S. laboratories reported they had destroyed all their samples of a dangerous flu virus that had been shipped around the world, but thousands of others remained unaccounted for yesterday as health authorities in 18 countries intensified efforts to prevent a deadly outbreak.
U.S. officials were investigating the cause of the mishap and racing to tighten restrictions on the handling of particularly dangerous flu strains while international health officials kept close watch for any sign of lab employees coming down with the flu.
CDC Director Julie L. Gerberding said tougher safety precautions will be expedited.
(John Bazemore -- AP)
President Bush had been briefed on the situation, which is "a high priority for our government," White House spokesman Scott McClellan said. "The risk to the public from these samples is low. . . . Nevertheless, we do not want to take any chances."
The World Health Organization said Canada, South Korea, Hong Kong and Singapore had confirmed destruction of their samples, but it was unclear how quickly other nations would comply.
"Things are now in full swing. We are getting daily updates, and Friday is our target," said Klaus Stohr, the WHO's top flu specialist. "We hope to hear all the samples are destroyed."
Although no infections had been reported and health authorities were hopeful that the risk was low, they said they were taking no chances.
"We are doing everything we can to make sure that there's no threat to human health," said Julie L. Gerberding, director of the federal Centers for Disease Control and Prevention.
The same strain of virus killed 1 million to 4 million people, including 70,000 in the United States, in the 1957-58 Asian flu pandemic. The virus has not been seen outside labs since 1968.
"Anyone born after 1968 would not have had any exposure to this and would be completely susceptible," Gerberding said. "We are doing everything we can to make sure this virus does not infect an individual or spread to the public at large."
The first clues began to emerge about why Meridian Bioscience Inc. of Cincinnati included the virus in test kits the company began shipping last fall to more than 6,000 facilities, mostly in the United States, as part of routine certification of their lab testing abilities.