Bird flu kills at least 4 500 chickens in Vietnam

A strain of bird flu virus that is not lethal to humans has killed at least 4 500 chickens in Vietnam, three months after an outbreak of the deadly H5N1 type that killed 16 people was declared over, officials said. The chickens on three farms in the Mekong Delta province of Bac Lieu were destroyed after testing positive for the H5 strain of the bird flu disease. While the H5 type is not known to be harmful to humans, another strain, H5N1, is lethal.

Last week, Nguyen Van Thong, deputy director of the agriculture ministry's animal health department, said many of the more than 10 000 poultry blood samples tested recently were H5 positive. He said the tests were done on samples from 37 cities and provinces around the country and that most of the positive results came from water fowl like ducks.

Chinese and US researchers reported on Monday that the frightening H5N1 strain of bird flu is mutating into an ever more deadly form in ducks and needs to be controlled quickly. A small outbreak of the H5N1 virus was found in a farm in the south of the country in May but was quickly contained, state media had reported.

Birdflu spread across many parts of Asia from late last year and killed millions of chickens and devastated poultry industries in several countries. It also killed eight people in Thailand. Vietnam declared itself free of the disease on March 30. People who got infected are believed to have caught the disease from close contact with sick birds. There were no confirmed cases of human-to-human transmissions. - Reuters