Bird flu still a threat Otago Daily Times, New Zealand - Nov 30, 2008 It was "only a matter of time" before the world - including Wakatipu - was struck by some form of influenza pandemic. "The World Health Organisation ...
Makassar stages first urban bird flu sim Jakarta Post, Indonesia - Nov 23, 2008 Makassar municipality organized a bird flu pandemic simulation in Tamangapa sub district, Manggala district, Makassar, South Sulawesi in an effort to ...
Avian and Pandemic Influenza: The Global Response NewsBlaze, CA - Nov 25, 2008 Therefore, the risk of an influenza strain with pandemic potential emerging from infected birds remains an extraordinarily persistent. ...
Terrorists could strike Britain by infecting country with bird flu Telegraph.co.uk, United Kingdom - Nov 26, 2008 It says the danger from pandemic diseases such as SARS and Avian Flu is growing and that existing arrangements to respond to serious incidents are ...
Bird flu suspects declared negative Jakarta Post, Indonesia - Nov 21, 2008 "The Makassar municipality is very cooperative so we will conduct a large bird flu pandemic simulation in March." A number of simulations have been staged ...
GPs refuse to treat bird flu patients NEWS.com.au, Australia - Aug 4, 2008 Australian Medical Association state president Dr Peter Ford said most doctors had received no formal training in dealing with a flu pandemic. ...
Listening needed to communicate bird flu risks Jakarta Post, Indonesia - Aug 5, 2008 Rather than being satisfied with the various kinds of one-size-fits-all "Beat The Bird Flu" campaigns, journalists need to lend their ears more to the ...
Bacteria, not influenza, were real killers in 1918 flu pandemic Thaindian.com, Thailand - Aug 5, 2008 Brundage said that government efforts to gird for the next influenza pandemic, bird flu or otherwise, ought to take notice and stock up on antibiotics. ...
Search This Blog using Google ScienceBlogs - Government efforts to gird for the next influenza pandemic - bird flu or otherwise - ought to take notice and stock up on antibiotics, says John Brundage, ...
Indonesian man dies of bird flu, official says The Associated Press - Aug 2, 2008 JAKARTA, Indonesia (AP) ? An Indonesian factory worker died of bird flu, bringing the death toll in the country worst hit by the virus to 112, ...
Bird flu claims one in Indonesia Independent Online, South Africa - Aug 4, 2008 Jakarta - The death toll from bird flu in Indonesia has risen to 112 after a 19-year-old man died from the virus last week, a health ministry official said ...
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Bird Flu Pandemic May Not Develop
MONDAY, July 31 (HealthDay News) -- A bird flu pandemic might not be imminent, as many health experts have feared, U.S. researchers now say.
When government researchers tried to combine the deadly H5N1 strain of bird flu with a common strain of flu that infects humans, they were unable to produce a strain that could be transmitted easily.
Health officials across the globe have worried that the bird flu virus that has killed 134 people worldwide might mutate, possibly in tandem with a more common flu virus, unleashing a new type of flu virus that could prove even more deadly because people's immune systems would not be able to fend off the disease.
The U.S. research, conducted with ferrets, offers some hope that a bird flu pandemic may not strike in the foreseeable future, if at all. But, the scientists cautioned, the genetics of flu viruses are unpredictable, and this study was based on one combination of viruses, when more than 50 possible combinations exist.
"Simple combinations of genes from both parent viruses have not led to enhanced transmissibility in the ferret," Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention, said at a press briefing Friday. "These data do not mean that H5N1 cannot develop into a pandemic strain. It means that the genetics of that transformation are more complicated than a simple one-to-one exchange. We are far from out of the woods on a global scale," she added.
While the finding doesn't mean the previous alarm has been much ado about nothing, it may have been "much ado about theory, about something speculative," said Dr. Marc Siegel, author of Bird Flu: Everything You Need to Know About the Next Pandemic, and a clinical associate professor of medicine at New York University School of Medicine.
"This does add emphasis to my previous analyses that multiple steps may be necessary before this particular bird flu can become a pandemic strain, and we would be wise to not take those steps for granted," Siegel said. "This doesn't prove that H5N1 can't be the pandemic virus either, but it shows that there seem to be several steps involved."
The new research also casts some doubt on how much of a breakthrough drug maker GlaxoSmithKline's new bird flu vaccine really is, Siegel added. "That vaccine is a major triumph if H5N1 is the next pandemic strain," he said. "But we'd be better to go to a more modern method where you don't have to know what the strain is. We wouldn't be stockpiling against something that looks like it's several steps away from being the pandemic."
The new findings are published in this week's issue of the Proceedings of the National Academy of Sciences.
The existing H5N1 bird flu strain has generated more fear than normal because of its virulence and ease of transmission among flocks of domestic birds. So far, bird flu has infected 231 people around the world and killed 134.
Human casualties remain largely confined to Asia and to people who have had close and prolonged contact with infected birds, such as poultry farm workers. Worries about bird flu have also led to the destruction of tens of millions of poultry, mostly in Asian nations, as officials struggle to contain the virus.
Three conditions are necessary for a pandemic to occur, Gerberding said: It must be a new virus for which humans lack antibodies; it must be a virus that can cause infection and disease; and it must be a virus that moves easily from one person to another.
The first two conditions have been met with the current H5N1 avian flu virus, but not the third.
A flu virus could acquire the ability to jump easily from person to person in one of two ways. First, genetic changes could take place over time that would make the virus progressively more transmissible, which is likely what happened during the 1918-1919 flu pandemic that killed between 20 million and 40 million people worldwide. Or the change could happen more suddenly, when one virus exchanges genetic material with another virus that's already circulating easily among humans. This is probably what happened with the 1957 and 1968 pandemics, Gerberding said.
"We assessed the more sudden approach," said the CDC's Jacqueline Katz, a co-author of the study. "The research was undertaken to better understand what changes are needed for H5N1 to acquire the properties of efficient transmissibility."
Katz and her colleagues used a 1997 version of the H5N1 bird flu virus and the H3N2 human virus that circulates each year. Ferrets were used for the study because viruses transmit the same way in these animals as they do in humans.
Because the researchers were trying to generate a virus that had the properties of a pandemic strain, all experiments were done under the highest possible level of security, Bio Safety Level 3.
Using a process called reverse genetics, the researchers mixed the eight genes of the H5N1 virus with the eight genes of the H3N2 virus. When the resulting viruses were tested in ferrets, they weren't able to transmit efficiently or cause severe disease. This remained the case even after the viruses were retransmitted five times from one healthy ferret to another one. In other words, the retransmissions didn't allow additional mutations to occur that would be necessary for a pandemic.
"The most important thing is the knowledge that this process isn't simple, and it's a complex procedure for a virus to acquire the properties of transmissibility," Katz said.
There are, in fact, more than 50 virus combinations out there.
"We chose to use some that had what we believed the greatest likelihood of being a good virus that grew well and was viable and therefore had the potential for transmission. But there are many other combinations that we could investigate in the future," Katz said.
Also, there are new versions of H5N1 and H3N2 that need to be tested.
The good news is that the ferret model used for this study as well as a guinea pig model currently under development are viable research tools.
"Overall, this work tells us we have a good research tool to assess the ongoing genetic changes that H5N1 viruses may acquire and that may enhance the ability to transmit efficiently," Katz said. "We need to continue these studies, and the first study has shown that we now have a good model for continued assessment of more recent strains for their ability to re-assort with human strains, and that is work that is ongoing at the moment."
But we're still far short of being out of the woods, Gerberding warned.
"The flu is always unpredictable," she said. "We've got strains emerging probably as we speak. Let's not use the word 'reassuring' in terms of what might happen with H5N1."