FOLLOWING an astonishing blunder that may have allowed a lethal pandemic flu strain to escape from the lab, researchers are calling for a higher level of security to be imposed on work with flu viruses.
Last week it was belatedly discovered that samples of the H2N2 flu virus, which killed millions during the Asian flu pandemic of 1957, had been sent to at least 4000 labs in 18 countries. The H2N2 was part of a kit designed to test the labs鈥� ability to identify viruses. The kits have been located and destroyed, but it will not be clear for weeks or months whether the virus has escaped through a lab worker becoming infected and passing it on.
The incident underscores the risk that the next flu pandemic might come not from Asian chickens but from a laboratory. 鈥淚 work with that virus at biosecurity level 2,鈥� says Earl Brown, a flu researcher at the University of Ottawa in Canada. 鈥淲e should probably move to level 3.鈥� Unlike level 2, that would require complete respiratory protection for lab workers. The Centers for Disease Control (CDC) in the US has also called for such changes.
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The kits containing H2N2 were made by Meridian Biosciences of Cincinnati, Ohio. Meridian has not said how H2N2 ended up in the kits. But one possibility, given that H2 grows very well in the lab, is that it contaminated cultures and replaced the strain that was meant to be sent out. This kind of problem is common, if seldom acknowledged (New Scientist, 20 September 2003, p 8).
The kits were sent out to labs between September and February. The mistake was discovered after a hospital lab in Vancouver, Canada, found that a sample from a patient tested positive for flu even though the patient had no flu symptoms. The hospital sent the sample to Canada鈥檚 National Microbiology Laboratory, which identified the H2N2 strain.
The Vancouver lab had tested the patient sample and the kit on the same day in the same ventilation cabinet. This suggests that the sample was contaminated directly and the patient was not infected.
However, the identification of H2N2 triggered alarms at the CDC and the World 午夜福利1000集合 Organization. No one born since 1968 has any immunity to H2 strains, as that was the year they disappeared, edged out by different strains. So if H2N2 has escaped from any of the labs, it could once again kill millions.
鈥淭he flu samples have been destroyed, but it will not be clear for weeks or months whether the virus has escaped鈥�
It would not be the first such incident. In 1977, an H1 strain identical to a long-vanished 1950 strain reappeared in China, possibly after being released by accident in Russia. Its progeny are still circulating today.
Julie Gerberding, head of the CDC, says that in the US, where most of the kits were sent, there have been no unusual patterns of flu this year such as an upsurge in flu in those under 37. But countries where surveillance is poorer might miss any escape.
