| Submit your comments on this article |
| Science & Technology |
| Avian Flu Mutating To More Easily H2H Strain, Not Yet Pandemic Strain |
| 2007-10-05 |
| 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. "The viruses that are circulating in Africa and Europe are the ones closest to becoming a human virus," Kawaoka said. Recent samples of virus taken from birds in Africa and Europe all carry the mutation, Kawaoka and colleagues report in the Public Library of Science journal PLoS Pathogens. "I don't like to scare the public, because they cannot do very much. But at the same time it is important to the scientific community to understand what is happening," Kawaoka said in a telephone interview. The H5N1 avian flu virus, which mostly infects birds, has since 2003 infected 329 people in 12 countries, killing 201 of them. It very rarely passes from one person to another, but if it acquires the ability to do so easily, it likely will cause a global epidemic. All flu viruses evolve constantly and scientists have some ideas about what mutations are needed to change a virus from one that infects birds easily to one more comfortable in humans. Birds usually have a body temperature of 106 degrees F, and humans are 98.6 degrees F usually. The human nose and throat, where flu viruses usually enter, is usually around 91.4 degrees F. "So usually 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. H5N1 caused its first mass die-off among wild waterfowl in 2005 at Qinghai Lake in central China, where hundreds of thousands of migratory birds congregate. That strain of the virus was carried across Asia to Africa and Europe by migrating birds. Its descendants carry the mutation, Kawaoka said. "So the viruses circulating in Europe and Africa, they all have this mutation. So they are the ones that are closer to human-like flu," Kawaoka said. Luckily, they do not carry other mutations, he said. "Clearly there are more mutations that are needed. We don't know how many mutations are needed for them to become pandemic strains." |
| Posted by:Anonymoose |
| #8 crosspatch: Again, as with so many other things associated with the Avian flu, it might transcend that as well. That is, one of the most lethal effects of the flu is that we have no immunity to it at all. In turn, this means that our immune response is dramatic. This is called the "cytokine storm" effect, and has been documented with Avian flu. It means that a person's own immune system will destroy their lungs, even if the Avian flu mutates to a much less directly harmful strain. This is because the H5 factor is so totally alien that harmful or harmless, the immune system overreacts to fight it. But so far, again unlike other flus, the Avian flu has managed to maintain its mortality rate at over 60%. At its height, the Spanish flu never beat 20% mortality. Flus typically never do that. I once remarked that short of a nuclear bomb, the killer flu is the greatest high probability threat to the United States. And that was based on the idea that it would be no more deadly than the Spanish flu. |
| Posted by: Anonymoose 2007-10-05 23:07 |
| #7 What the media aren't telling people is that if it mutates to a form more easily transmitted by humans, it could ALSO mutate into forms that are much less deadly. So while a lot of people might get it, it could mutate in such a fashion as to be no deadlier than typical influenza virii that circulate every year. To jump to the conclusion that it will be as deadly as it is now in its mutated form is simply fantasy. While that *might* be the case, chances are that it won't be the case. |
| Posted by: crosspatch 2007-10-05 22:30 |
| #6 Darrell: Nope. The max time frame is about 2 years. This is because the animal vectors act much like a giant computer, continually deriving new and better strains, which then compete against each other. Thousands of H2H iterations will occur before even one of them is introduced to a human. This current mutation may increase the number of human infections by a factor of 10 or 100 in the next year, as breeding in the upper trachea and sinuses is *the* most important mutation needed for easy H2H transmission. And since the lethality of the disease is far worse than even the Spanish flu, its 2-week-or-so cyclic entry into H2H pandemic is going to be dramatic. That is an outbreak, during which the disease silently spreads far beyond its boundaries, followed by about a two week hiatus, followed by exponential growth in the next outbreak. |
| Posted by: Anonymoose 2007-10-05 22:06 |
| #5 "an avian flu pandemic is seen by the worldwide health community as inevitable" Even this scientist says "We don't know how many mutations are needed for them to become pandemic strains." The mutations required could take 200 more years to develop or maybe even not develop at all. This is Al-Gore-quality doom and gloom. |
| Posted by: Darrell 2007-10-05 21:33 |
| #4 Ever since my childhood, Guam locals would simply chop off the heads/parts of known or preceived infected chickens, plus surrounding tissue(s) for good measure, then boil, broil, or barbecue the thing in a timely manner. I know of no one here on Guam thats ever gotten sick from Bird Flu per se. IMO > JUST MAKING THE WORLD SAFE FOR PROCESSED/FACTORY MEAT [read - BIG GOVT + BIG UNIONS? GLOBAL UNIONS?]. |
| Posted by: JosephMendiola 2007-10-05 20:41 |
| #3 Darrell: just because you haven't seen more stuff on the progress of the Avian flu, doesn't mean it isn't out there: http://www.birdflubreakingnews.com/ http://www.pandemicflu.gov/ http://www.fluwikie.com/ https://www.singtomeohmuse.com/viewforum.php?f=1 http://newsnow.co.uk/newsfeed/?name=Bird+Flu The bottom line is that an avian flu pandemic is seen by the worldwide health community as inevitable, and when it finally bursts out, it is going to be a mother. |
| Posted by: Anonymoose 2007-10-05 19:48 |
| #2 I, for one, welcome our mutated virus masters. |
| Posted by: Rex Mundi 2007-10-05 17:55 |
| #1 This is the first bird flu doom-and-gloom we've heard for awhile. Their research grants must be running out. |
| Posted by: Darrell 2007-10-05 17:41 |