Laboratory tests have shown a drug extracted from the medicinal herb St John’s Wort can be used to treat poultry infected with bird flu, a veterinary professor said.Field tests in Vietnam had also been satisfactory, he added.
The results were released as World Health Organisation representatives prepared to meet officials in Beijing to discuss concerns about the mainland’s use of the human antiviral drug amantadine to suppress bird flu outbreaks. The UN Food and Agriculture Organisation said yesterday it was also seeking clarification from Beijing.
Liang Jianping , of the Lanzhou Institute of Animal and Veterinary Sciences, said the compound hypercin had been found to be effective in treating and preventing bird flu.
“We have found hypercin can kill 99.99 per cent of H5N1 and H9N2 virus in vitro within 10 minutes,” Professor Liang said.
He and his team went to Vietnam for field tests in April. “The findings there were also pretty satisfactory,” he said.
In one poultry farm in Hanoi, more than 70 per cent of 4,000 ducks were infected with H5N1, but after they were administered hypercin, deaths tailed off dramatically. The day after they received the drugs, 37 ducks died; on the second day the toll was 17 and on the third day, three. On the fourth day, none died.
The team conducted another field test on a farm in the bird-flu-riddled province of Ha Tay. Professor Liang said that while the epidemic raged on neighbouring farms, not one of the 3,000-plus chickens given hypercin on the test farm had died.
While noting that hypercin was not a vaccine, the professor pointed out that “since the avian flu virus remains very unstable and versatile, it cannot be prevented by a single vaccine”.
“It is very gratifying that hypercin can actually stop the spread of the disease given that in the onset of avian flu, often more than one virus strain is involved,” he said.
He added that it was important to control the disease in poultry because no effective human vaccine against bird flu existed.
H5N1 has infected more than 100 people in Southeast Asia since late 2003, killing at least 54. The first human infection by the virus was in Hong Kong in 1997, when six of 18 people infected died.
The hypercin treatment, which could be licensed by the Ministry of Agriculture for manufacture within two years, may not help control outbreaks among migratory birds.