Friday, October 05, 2007

Bird Flu - Taking Note of the News...

This may not mean anything, but due diligence requires that we take note:

The H5N1 bird flu virus has mutated to infect people more easily, although it still has not transformed into a pandemic strain, researchers said on Thursday.

The changes are worrying, said Dr. Yoshihiro Kawaoka of the University of Wisconsin-Madison.

"We have identified a specific change that could make bird flu grow in the upper respiratory tract of humans," said Kawaoka, who led the study.

"[U]sually the bird flu doesn't grow well in the nose or throat of humans," Kawaoka said. This particular mutation allows H5N1 to live well in the cooler temperatures of the human upper respiratory tract.

"Clearly there are more mutations that are needed. We don't know how many mutations are needed for them to become pandemic strains."
The next pandemic flu might be next week, might be next year, might be in 20 years. The pandemic flu might not come from birds, either.

As Hamlet said, "The readiness is all."

(Related item: The California Association of Health Facilities has issued a new pandemic flu workbook for long-term care providers.)

Update Oct. 8, 2007: A bit of perspective from Effect Measure:
This is pretty scary sounding but it isn't new scary sounding. Kawaoka confirmed and filled in the picture about a mutation we already knew about, which is why he looked at it more closely in this paper. As far as we know the suspicion that a mutation in the PB2 gene at position 627 that substitutes lysine for glutamic acid (the mutation is written E627K in shorthand) goes as far back as 1992 when Subbarao, London and Murphy showed it was needed for a bird virus to infect mammalian cells. The idea that temperature is important was reported by Massin and colleagues in 2001.

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