H5N1 – mutation towards a pandemic strain gathers pace

[5 October 2007 - 15h29]

American researchers have discovered that a “key step” has been reached in the mutation of the H5N1 virus which could allow it to transform into a human flu virus, thus opening the door to a pandemic. For the moment however, it should be pointed out that H5N1 remains a purely avian virus.

In the journal Plos Pathogens Dr Yoshihiro Kawaoka of the University of Wisconsin-Madison explains that “mutation on one of the H5N1 viral proteins has been identified in samples taken from sick birds from Europe and Africa”. This transformation could allow the avian virus to tolerate our 37° body temperature (the body temperature of birds is about 41°) and therefore to develop in our upper respiratory tract.

Indeed, the mutation could provide the H5N1 virus with one of the vital keys for multiplying in the human body. “These keys would unlock the receptor bolts fitted to our cells”, states Dr Kawaoka. But there’s no need for immediate concern, we haven’t reached that stage yet. “H5N1 will have to mutate several times more, Dr Kawaoka continues.

In fact, the French health authorities have decided to lower the level of risk by one notch across the whole country – today avian flu risk has been reduced from “high” to “moderate”, in accordance with the National Flu Pandemic Prevention Plan. This lowering of the risk level brings with it the relaxation of certain restrictions: gatherings involving birds are now permitted, confinement is lifted and the conditions governing the participation of homing pigeons in competitions have been eased. Only at-risk wetland areas will fail to benefit from these relaxations.

Source : PloS Pathogens, 4 October 2007, French Agriculture and Fishing ministry of, 5 Octobre 2007

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