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Sbharris[atsign]ix.netcom.com wrote:
> fresh~horses wrote:
> > Viruses develop resistance to flu drugs
> >
> > By HELEN BRANSWELL
> >
> > Wednesday, September 21, 2005 Posted at 9:02 PM EDT
> >
> > Canadian Press
> >
> > Toronto - Human flu viruses are becoming increasingly resistant to
> > the class of drugs known as adamantanes, one of only two existing
> > classes of flu drugs, a new study released Thursday shows.
> >
> > The authors say their findings call into question the future usefulness
> > of the adamantane or M2 inhibitor drugs - a warning echoed by a
> > leading antiviral expert who was not involved in the work.
> >
> > That independent expert, Dr. Frederick Hayden suggested that in light
> > of the findings the drugs amantadine and rimantadine should not play a
> > significant role in drug stockpiles put together to help a country
> > weather a flu pandemic.
> >
> > "I think that these data present real concerns about how can we use
> > this class in the future. And it certainly says it makes little sense
> > to make it an important part of drug stockpiles for pandemic
> > response," said Dr. Hayden, a scientist at the University of Virginia
> > who is on secondment to the World Health Organization.
> >
> > "It takes one of the arrows out of our quiver, as it were."
> >
> > Only one of the drugs, amantadine, is sold in Canada. The Public Health
> > Agency of Canada has plans to add substantial quantities of the drug to
> > the country's pandemic stockpile.
> >
> > The M2 inhibitors are off-patent and much cheaper than the only other
> > class of flu drugs, the patent-protected neuraminidase inhibitors
> > oseltamivir (Tamiflu) and zanamivir (Relenza).
> >
> > The first author of the study was less definitive about the future of
> > the drug, saying he felt it was too soon to consider the class lost for
> > good.
> >
> > "It's hard to tell. We don't know exactly what caused the resistance.
> > And it's possible that if it was caused by a spontaneous mutation the
> > virus could mutate and go back the other way," said Rick Bright of
> > the strain surveillance section of the influenza branch at the U.S.
> > Centers for Disease Control in Atlanta.
> >
> > "I certainly wouldn't give up hope on any class of (flu) drugs at
> > this point."
> >
> > But the paper itself warns agencies and governments purchasing pandemic
> > stockpiles that amantadine and rimantadine "will probably no longer
> > be effective for treatment or prophylaxis" - using the drugs to
> > ward off illness - "in the event of a pandemic outbreak of
> > influenza."
> >
> > Dr. Bright and his co-authors analyzed human flu viruses submitted to
> > the CDC - in its role as a WHO influenza reference laboratory -
> > between Oct. 1, 1994 and March 31, 2005. The aim was to see if the
> > rates of resistance to the adamantane drugs changed over that period.
> >
> > The scientists screened more than 7,000 human influenza A viruses
> > looking for specific genetic mutations known to confer resistance to
> > the adamantane drugs.
> >
> > Rates of resistance started to rise in China in 2000 and spiked between
> > 2002 and 2003. Additional spikes occurred in 2003 in viruses from Hong
> > Kong, Taiwan and South Korea.
> >
> > "Viruses collected in 2004 from South Korea, Taiwan, Hong Kong and
> > China showed drug-resistance frequencies of 15 per cent, 23 per cent,
> > 70 per cent and 74 per cent respectively," they wrote in the article,
> > published by the medical journal The Lancet.
> >
> > The trend extends beyond Asia. Thirty per cent of Canadian viruses
> > collected in 2005 and analyzed by the team were resistant to the drugs.
> > Resistance rates were also significantly above historical values in a
> > number of countries in South, Central and North America and in Europe.
> >
> > The authors can't say what is behind the increase in resistance but
> > they hypothesize it may either be driven by high use of the drugs in
> > parts of Asia, where they can be bought without prescription or because
> > of a spontaneous mutation.
>
>
> COMMENT:
>
> Not mentioned is a Washington Post story from last June which reported
> that the Chinese had simply been trying to control bird flu epidemics,
> starting in the late 90's, by simply adding cheap amantadine to
> chickenfeed. An incredibly idiotic practice. And just before the time
> resistance started to emerge in China and Hong Kong to this drug (at
> the beginning of the 21st century), and where it remains the highest by
> far, even now. The Chinese government denies all. But the Chinese
> government has not been known in the past for its veracity.
>
> SBH
Yep. In The Australian today, the headline "Asian drug resistance adds
to bird flu fears" was over a story saying that more than 70% of
flu-sufferers in China and Hong Kong were drug-resistant because
Chinese farmers had used cheap anti-viral drugs to try and keep their
poultry disease-free.
Idiots. Almost as stupid as feeding cows meat.
Cathy
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