華盛頓郵報報導, 為了防止雞瘟爆發, 中國政府早於1990鼓勵雞農為雞隻注射治療人類用的抗生素, 這做法違反了國際畜牧業的規定, 而動物學家認為, 很可能是這種違反規定的做法導致H5N1的爆發...
節錄自Washing Post
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....
....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....
...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....
...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 The veterinarian asked that his name not be published because he feared for his livelihood.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 for each kilogram of chicken body weight.