Germs on the Loose
A deadly flu virus somehow got mailed to laboratories around the world
A world already jittery over the looming threat of an influenza pandemic got a new jolt last week, when health officials revealed that the virus that killed at least 1 million people in the 1957-58 flu pandemic had been mailed to about 4,000 medical laboratories in the United States and 17 other countries.
Officials with the Centers for Disease Control and Prevention and the World Health Organization rushed to order the laboratories to destroy the errant virus while sending a reassuring message to the public: "While the risk of the situation is very low, we're not taking any chances, and we're doing everything we can to make sure there's no threat to human health," said Julie Gerberding, head of the CDC. No one appears to have gotten sick, but Gerberding noted that because this particular flu virus hasn't existed outside labs since 1968, anyone under age 37 would lack immunity and "would presumably be completely susceptible."
And though most of the virus appears to have been destroyed, many troubling questions remain, not the least of which are how a routine laboratory-testing program could have sparked an international health scare and why it took so long for anyone to realize that something was amiss.
The incident has brought calls from Congress and the White House for better controls on potentially devastating microbes. Klaus Stohr, head of WHO's influenza program, said that public announcement of the problem was delayed until destruction of the virus was well underway in order to prevent it from falling into the hands of terrorists. "There is a biosecurity risk, and we did not want to arouse interest."
The problem started last September when Meridian Bioscience Inc., a Cincinnati manufacturer of medical diagnostic tests, started sending proficiency test kits to medical laboratories in hospitals, doctors' offices, and clinics in all 50 states and 17 countries abroad. The kits, which contain unidentified samples of viruses and other pathogens, are used regularly to rate the labs' ability to detect common infectious agents. The bugs used usually are common microbes that pose little risk to lab workers or the public.
Killer kits. But it now appears that the flu virus sent out was not common at all. On March 26, the Canadian National Microbiology Laboratory in Winnipeg, Manitoba, identified a sample taken from a Vancouver woman as H2N2, the killer 1957 virus. Fearing that the virus was loose in Vancouver, scientists at the Canadian Public Health Agency tracked down the patient and were relieved to discover that she hadn't had H2N2 flu. It took almost two weeks for the investigators to conclude that a worker in a Vancouver lab had had the woman's sample open next to the proficiency testing sample, and that the two must have cross-contaminated.
The Canadians called CDC and WHO, as well as the College of American Pathologists, which had hired Meridian to send the samples. On April 8, WHO and CDC ordered labs to destroy the virus, and last Monday, they asked that workers be monitored for signs of illness. By week's end, 80 percent of the labs had reported that they had complied.
The danger may have dissipated, but it's still unclear why H2N2 flu would have been in the test kits. The customs label on the sample that led to the Canadian discovery said it was H3N2, a fairly benign strain of regular flu. The CDC and the National Institutes of Health had been considering reclassifying H2N2 from a level 2 biohazard, the category for annual flu viruses, to a level 3, which requires special ventilation and respiratory protection for workers. (Level 4, in which workers wear moon suits, is reserved for particularly deadly agents like Marburg and smallpox.) In the midst of last week's mess, Gerberding said that review would be expedited.
If a mistake was made at Meridian, the company isn't saying so. "There is not good communication between us at the moment," said Jared Schwartz, a pathologist and spokesman for the College of American Pathologists.
It is fortunate that the Canadian doctors noticed that a woman with no flu symptoms was testing positive for the disease and sent the sample on for sophisticated testing. Otherwise, no one would have known that H2N2 was at large, because standard medical labs have no test to detect it. The other way to discover it, scientists say, would be an actual outbreak.
This story appears in the April 25, 2005 print edition of U.S. News & World Report.
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