http://www.newswise.com/articles/view/525201/Scientists Find Mutations That Let Bird Flu Adapt to Humans
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AVIAN INFLUENZA, HUMAN INFLUENZA, PANDEMIC, RECEPTORS, INFECTION
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By comparing influenza viruses found in birds with those of the avian virus that have also infected human hosts, researchers have identified key genetic changes required for pandemic strains of bird flu.
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The new work, reported in the Nov. 16 issue of the journal Nature, illustrates the genetic changes required for the H5N1 avian influenza virus to adapt to easily recognize the receptors that are the gateway to human cells.
"We identified two changes that are important," says Yoshihiro Kawaoka, the senior author of the Nature paper and a virologist at the University of Wisconsin-Madison School of Veterinary Medicine. "Both changes are needed for the H5N1 virus to recognize human receptors."
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To be successful, a virus must be able to recognize and attach to a host cell. But human and avian influenza viruses recognize different cell receptors. Avian flu viruses have demonstrated an ability to evolve to easily infect humans by exchanging genes with human viruses that subsequently permit them to recognize human receptor molecules and gain easy access to cells, typically in the human respiratory system.
The change is thought to occur when human patients are exposed at the same time to a human flu virus and an avian flu virus. Most viruses, including influenza, readily swap genes with one another.
In the new study, conducted by an international team of researchers, the viruses isolated from human patients in Vietnam and Thailand could recognize both human and avian cell receptors. By contrast, the viruses found in chickens and ducks could only recognize the receptors on avian cells.
The work helps flesh out the changes that have occurred in the worrisome strain of avian influenza virus known as H5N1, a strain some fear could be the organism that will trigger a pandemic of virulent human influenza. The avian virus has already changed dramatically from when it was first identified in 1997, says Kawaoka, who also holds an appointment at the University of Tokyo.
"There are big differences between the virus first found in 1997 and the virus we see now," Kawaoka explains. "We are watching this virus turn itself into a human pathogen." The mutations found by Kawaoka's group have not yet conferred a complete ability on avian flu to easily recognize the topography of human cells, but they are key steps on that pathway. More mutations, says Kawaoka, will be required for the virus to fully adapt to humans, but it is not known how many mutations are needed for such a change.
However, if scientists are able to continue to monitor and secure viral isolates from humans infected with bird flu, they may be able to map a mutation trajectory that will help predict when the avian virus will cross the threshold to become a human pathogen.
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and this from yesterday
http://www.pandemicflu.gov/plan/pdf/panflureport3.pdfIn early 2007, a team of pandemic flu experts and communicators will tell meetings of senior news executives that human-to-human transmission of H5N1 has been identified in a village overseas. Later in the day, they will be told the disease has spread across a region overseas. And finally, they will be told that human cases have been reported in the United States.
The announcements will be fake, part of an exercise to test how the media – and the experts – will respond should the day come when similar announcements have to be made for real. The two sides will work through the challenges of getting and reporting timely accurate information.
One challenge is how to keep the public informed, without undue alarm, in situations where there is high interest and little new information, situations that could develop, for instance, while waiting for the results of confirmatory testing. The exercise will be repeated in six other cities, reaching national, regional, Hispanic and African-American media.
and from yesterday
http://www.telegraph.co.uk/money/main.jhtml?xml=/money/2006/11/13/cngsk13.xmlSeveral governments around the world have promised to send in the army to protect GlaxoSmithKline manufacturing plants that produce bird flu vaccine should a pandemic break out, the drug maker's chief executive, Jean-Pierre Garnier, has said.
"People don't realise the disorder which comes from a scary event such as a true pandemic. It is not going to be the time to line up to your friendly pharmacist because there will be hundreds of people there. There will be panic episodes," Mr Garnier said.
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