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"cathyb" <cathybeesley@xxxxxxxxxxxxxxx> wrote in message
news:1127447010.154446.96980@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> 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
>
Were they buying the cheap drugs from Canada?
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