Tuesday, May 15, 2007

Experts fear escape of 1918 flu from lab

I should have read this more carefully when I cited it in the original post.

Experts fear escape of 1918 flu from lab
10:33 21 October 2004
Exclusive from New Scientist Print Edition.
Debora MacKenzie

The 1918 flu virus spread across the world in three months and killed at least 40 million people. If it escaped from a lab today, the death toll could be far higher. “The potential implications of an infected lab worker – and spread beyond the lab – are terrifying,” says D. A. Henderson of the University of Pittsburgh, a leading biosecurity expert.

Yet despite the danger, researchers in the US are working with reconstructed versions of the virus at less than the maximum level of containment. ....

The latest work was done by Yoshihiro Kawaoka at the University of Wisconsin at Madison. His team showed that adding the 1918 gene for the surface protein haemagglutinin to modern viruses made them far deadlier to mice. The researchers also found that people born after 1918 have little or no immunity.

The team started the work at the highest level of containment, BSL-4, at Canada’s National Microbiology Laboratory in Winnipeg. Then they decided the viruses were safe enough to handle at the next level down, and did the rest of the work across the border in a BSL-3Ag lab in Madison. The main difference between BSL-4 and BSL-3Ag is that precautions to ensure staff do not get infected are less stringent: while BSL-4 involves wearing fully enclosed body suits, those working at BSL-3Ag labs typically have half-suits.

Kawaoka told New Scientist that the decision to move down to BSL-3Ag was taken only after experiments at BSL-4 showed that giving mice the antiviral drug oseltamivir (Tamiflu) in advance prevented them getting sick. This means, he says, that if all lab workers take oseltamivir “they cannot become infected”. ...

Yet this assumes that the mouse results apply to humans. And the findings have not been published. In similar experiments, Terrence Tumpey’s team at the US Department of Agriculture’s poultry research lab in Athens, Georgia, got quite different results: they found that mice given oseltamivir still got sick and 1 in 10 died. It is not clear why Kawaoka’s mice fared better.

What is more, all the safety precautions are aimed at preventing escape, not dealing with it should it occur. If any of Kawaoka’s lab workers are exposed to the virus despite all the precautions, and become infected despite taking oseltamivir, the consequences could be disastrous.

“I experienced disbelief…regarding the decision to relocate the reconstructed 1918 influenza strain from a BSL-4 facility to a BSL-3 facility, based on its susceptibility to antiviral medication,” Ronald Voorhees, chief medical officer at the New Mexico Department of Health, wrote on ProMED-mail, an infectious diseases mailing list....

Unbelieveable.

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