Bird Flu Drug Rendered Useless [by use in animals]

[Guest guest]

Hi All,

 

See this, from:

http://archives.econ.utah.edu/archives/a-list/2005w24/msg00046.htm

 

This is scary stuff when set against prediction by some experts [see:

www.fluwikie.com/index.php?n=Science.OpinionAboutAFluPandemic ]

of an avian-flu pandemic early next year.

 

Herbalists, should we renew discussion of CHM Formulas that may

address severe viral respiratory diseases?

 

Best regards,

Phil

 

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Bird Flu Drug Rendered Useless: Chinese Chickens Given Medication

Made for Humans

 

By Alan Sipress Washington Post Foreign Service Saturday, June 18,

2005; A01

 

HONG KONG -- Chinese farmers, acting with the approval and

encouragement of government officials, have tried to suppress major

bird flu outbreaks among chickens with an antiviral drug meant for

humans, animal health experts said. International researchers now

conclude that this is why the drug will no longer protect people in case of

a worldwide bird flu epidemic.

 

China's use of the drug amantadine, which violated international

livestock guidelines, was widespread years before China acknowledged

any infection of its poultry, according to pharmaceutical company

executives and veterinarians. Since January 2004, avian influenza has

spread across nine East Asian countries, devastating poultry flocks and

killing at least 54 people in Cambodia, Thailand and Vietnam, but none

in China. World Health Organization officials warned the virus could

easily undergo genetic changes to create a strain capable of killing tens

of millions of people worldwide.

 

Although China did not report an avian influenza outbreak until February

2004, executives at Chinese pharmaceutical companies and

veterinarians said farmers were widely using the drug to control the virus

in the late 1990s. The Chinese Agriculture Ministry approved the

production and sale of the drug for use in chickens, according to officials

from the Chinese pharmaceutical industry and the government, although

such use is barred in the United States and many other countries. Local

government veterinary stations instructed Chinese farmers on how to

use the drug and at times supplied it, animal health experts said.

 

Amantadine is one of two types of medication for treating human

influenza. But researchers determined last year that the H5N1 bird flu

strain circulating in Vietnam and Thailand, the two countries hardest hit

by the virus, had become resistant, leaving only an alternative drug that

is difficult to produce in large amounts and much less affordable,

especially for developing countries in Southeast Asia.

 

" It's definitely an issue if there's a pandemic. Amantadine is off the

table, " said Richard Webby, an influenza expert at St. Jude Children's

Research Hospital in Memphis.

 

Health experts outside China previously said they suspected the virus's

resistance to the medicine was linked to drug use at poultry farms but

were unable to confirm the practice inside the country. Influenza

researchers at the U.S. Centers for Disease Control and Prevention, in

particular, have collected information about amantadine use from

Chinese Web sites but have been frustrated in their efforts to learn

more on the ground.

 

China has previously run afoul of international agencies for its response

to public and agricultural health crises, notably the SARS epidemic that

began in 2002. China's health minister was fired after the government

acknowledged it had covered up the extent of the SARS outbreak by

preventing state-run media from reporting about the disease for months

and by minimizing its seriousness.

 

In interviews, executives at Chinese pharmaceutical companies

confirmed that the drug had been used since the late 1990s, to treat

chickens sickened by bird flu and to prevent healthy ones from catching

it. " Amantadine is widely used in the entire country, " said Zhang Libin,

head of the veterinary medicine division of Northeast General

Pharmaceutical Factory in Shenyang. He added, " Many pharmaceutical

factories around China produce amantadine, and farmers can buy it

easily in veterinary medicine stores. "

 

Zhang and other animal health experts said the drug was used by small,

private farms and larger commercial ones. Amantadine sells for about

$10 a pound, a fraction of the drug's cost in Europe and the United

States, where its price would be prohibitive for all but human

consumption.

 

Two months before China first reported a bird flu outbreak in poultry to

the World Animal Health Organization in February 2004, officials had

begun a massive campaign to immunize poultry against the virus. They

have now used at least 2.6 billion doses of a vaccine. But researchers in

Hong Kong have reported that the H5N1 flu virus has been circulating in

mainland China for at least eight years and that Chinese farms suffered

major outbreaks in 1997, 2001 and 2003. Scientists have traced the

virus that has devastated farms across Southeast Asia in the last two

years to a strain isolated from a goose in China's Guangdong province

in 1996.

 

The U.N. Food and Agriculture Organization has long recommended

that countries try to eradicate infectious animal diseases by slaughtering

infected flocks and increasing safety measures on farms. Last year, the

FAO also suggested that countries consider vaccinating their poultry

against bird flu. But the guidelines never recommended the use of

antiviral drugs such as amantadine, which, unlike vaccination, has been

proven to make viruses resistant, officials said.

 

In 1987, researchers at a U.S. Department of Agriculture laboratory

demonstrated that bird flu viruses developed drug resistance within a

matter of days when infected chickens received amantadine. Still, a

veterinarian with personal knowledge of livestock practices across

China said Chinese farmers responded to the bird flu outbreak by

putting the drug into their chickens' drinking water. The veterinarian

asked that his name not be published because he feared for his

livelihood.

 

" This would explain why we're seeing such high resistance levels, " said

Michael T. Osterholm, director of the Center for Infectious Disease

Research and Policy at the University of Minnesota. While various

antibiotics have lost their effectiveness because of overuse, he said, the

emergence of resistance to amantadine is unprecedented because it is

an antiviral. " This is the first example of an antiviral drug that was used

for animal production that has major implications for human health, "

Osterholm said.

 

A popular Chinese handbook, titled Medicine Pamphlet for Animals and

Poultry, provides farmers and livestock officials with specific

prescriptions for amantadine use to treat chickens and ferrets with

respiratory viruses. The manual, written by a professor at the People's

Liberation Army Agriculture and Husbandry University and issued by a

military-owned publishing company, prescribes 0.025 grams of

amantadine/kg chicken body weight.

 

Farmers also use the drug to prevent healthy chickens from catching

bird flu, giving it to their poultry about once a month or more often when

the weather is liable to change and chickens are considered susceptible

to illness, veterinary experts said. The antiviral is often mixed with

Chinese herbs, vitamins and other medicine.

 

In the United States, amantadine was approved in 1976 by the Food

and Drug Administration for treating influenza in adults. Amantadine and

it sister drug, rimantadine, known collectively as amantadines, work by

preventing a flu virus from reproducing itself. Both are now ineffective

against the H5N1 strain. International health experts stressed that

amantadine could have been vital in stanching the spread of the bird flu

virus in the early weeks of an epidemic. Now, the only alternative is

oseltamivir and closely related zanamivir, which stop the flu virus from

leaving infected cells and attacking new ones. Oseltamivir is easier to

use and has far greater sales.

 

" Amantadine is the cheapest drug against flu, " said Malik Peiris, an

influenza expert at the University of Hong Kong. " It is much more

affordable for many countries of the region. Now, it is clearly no longer

an option. " Special correspondents Ling Jin in Beijing and K.C. Ng in

Hong Kong contributed to this report.

 

-- " Life sure is weird but what else am I to know? " [Jason Pierce]

 

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Best regards,

 

 

Tel: (H): +353-(0) or (M): +353-(0)

 

 

 

 

Ireland.

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" Man who says it can't be done should not interrupt man doing it " -

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