Scientists have reached no firm conclusions on why the flu is so contagious, but a leading theory is its adaptability. The World Health Organization fears that bird flu could combine with a human flu to create a dangerous mutant form.
Dr. Klaus Stohr, head of the influenza program for the United Nations agency, recommended yesterday that people with bird flu be quarantined to avoid contact with sufferers of regular influenza. But he said he saw no need for the kind of travel warnings that the WHO issued during last year's SARS outbreak, which killed nearly 800 people worldwide.
"We have to put things into perspective," he said. "There is a chance that something can go wrong, but . . . if we act decisively now, then there still is a window of opportunity here to control the disease before it takes on global proportions."
Killing chickens in affected countries is "the key to the solution of the whole problem," Stohr added. "We do not have a problem of international spread by infected humans. We may have a problem of international spread by birds."
Thailand's government confirmed the disease was present in its poultry population. It also said tests showed that two boys, ages 6 and 7, have the virus and two people are suspected of having it. One, reportedly a 56-year-old man who raised fighting cocks, died yesterday, the government said.
Cambodia also confirmed its outbreak while Laos held an emergency meeting yesterday to evaluate cases of dead poultry there.
Farmers in Thailand have been saying for more than a week that their chickens, like those in neighboring countries, were dying of bird flu. But until yesterday, officials had maintained that the chickens were suffering from fowl cholera, which they said posed no danger to people.
Prime Minister Thaksin Shinawatra denied that his government tried to cover up the situation. "We were waiting for the tests," he said. "I know what I'm doing."
Thailand is among the world's top five poultry exporters. Stocks in chicken producers plunged. The European Union joined Japan, which are Thailand's largest chicken markets, in slapping import bans. Switzerland, Hong Kong, Singapore, and the Philippines have done likewise.
On Wednesday, Thailand will host a meeting of agriculture and health ministers from countries affected by bird flu.
The WHO will send two influenza specialists to Thailand this weekend to help cope with the outbreak.
Scientists think people get the disease through contact with sick birds. No evidence exists of person-to-person transmission. But health officials worry that the avian virus could mutate by combining with an influenza virus to allow human transmission.
