This is Bob Doughty with the VOA Special English Agriculture Report.
The chicken industry in East Asia has grown quickly in recent years. But now the industry must deal with findings that the avian influenza virus is more widespread than was thought.
In the last two weeks, China, Thailand and Vietnam all reported new cases of bird flu. China and Thailand are two of the largest poultry producers in the world.
Scientists were not immediately sure if this was a new virus or a continuation of the major outbreaks earlier this year. But a top official of the United Nations Food and Agriculture Organization said the new cases are not a surprise.
Joseph Domenech says governments need to recognize that the virus will continue to spread and different ones could also appear. He says doing away with the avian flu virus "should be considered, at best, as a long-term task."
By the end of last week workers had killed tens of thousands of chickens and ducks to stop the spread of the virus. But a World Health Organization official, Doctor Shigeru Omi, said there was still a great risk to public health.
Earlier this year, the avian flu virus killed at least twenty-three people in Southeast Asia. The W.H.O. says thirty-four people in all became infected. At that time, workers killed about one-hundred million chickens and other birds in an effort to stop the infection. Scientists fear that the virus could become able to spread from person to person.
Medical experts in China recently found that the h-five-n-one virus is becoming more dangerous to mammals. They studied viruses collected over four years. They observed the effects on chickens, mice and ducks.
The researchers found that the more recent forms of the virus were more deadly to mice than earlier versions. They say immediate action is needed to prevent the spread of avian flu viruses from ducks into chickens or mammals. The virus infects ducks but does not make them sick. The study appears this week in the Proceedings of the National Academy of Sciences.
And a study last week in the magazine Nature says wild birds may have added to the increasing spread of the virus in Asia. The researchers say their results suggest that h-five-n-one has become firmly rooted in the area. They say these developments may be a threat to people and animals worldwide.
This VOA Special English Agriculture Report was written by Caty Weaver and Mario Ritter. This is Bob Doughty.