Bird flu pandemic just "three mutations" away, scientists show

Bird flu pandemic just "three mutations" away, scientists show

A bird flu pandemic may be close to being a real threat after scientists discovered the virus is already just "three mutations" away from evolving into a strain which would be able to pass from human to human.
By Richard Alleyne, and Nick Collins 22 Jun 2012
Avian H5N1 influenza can currently only be transmitted to humans from birds, meaning it cannot spread quickly through the air between large groups of people.
But a recent study at Cambridge University shows that there are strains already existing which are just "three mutations" away from being passable form one human to another.
It suggests the airborne strain could evolve naturally in the wild – even in one person.
Prof Derek Smith, one of the Cambridge researchers, said the study had shown that the risk – like an
earthquake fault line – did exist but remained difficult to say if and when it might become reality.
He said: "With the information we have, it is impossible to say what the exact risk is of the virus becoming airborne transmissible among humans.
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"However, the results suggest that the remaining three mutations could evolve in a single human host, making a virus evolving in nature a potentially serious threat."
He said that the research meant we knew what was coming which helped "immensely".
The original study was held back from publication for several months because American authorities feared the information could pose a security threat.
But the paper by Ron Fouchier of the Erasmus Medical Center in Rotterdam highlights that the virus was not deadly to ferrets which caught it by breathing it in, easing initial concerns that it could be made into a bioweapon by terrorists.
Prof Wendy Barclay, Chair in Influenza Virology at Imperial College London, said: "How much of a fitness cost these changes confer individually or when combined and in which species, will be important to establish before we can really assess how close we are to the H5 pandemic.
"Hopefully more work from the biologists to help the mathematicians address how mutant influenza viruses with new properties evolve within a host will increase our ability to estimate the risks of pandemics."