The death toll from bird flu in Asia climbed to 13 today as the World Health Organization tried to dampen fears of a major human outbreak.
A seven-year-old boy became the fourth person to die from the disease in Thailand. There have been nine fatalities in Vietnam.
An outbreak in China's poultry stocks appears to be widening with new confirmed or suspected cases reported in six provinces.
After announcing yesterday that investigators could not trace the infections of two Vietnamese women to contact with chickens and that human-to-human transmission could not be ruled out, the WHO sought to calm fears that the case might foreshadow a global flu pandemic.
"We do not at this stage have a pandemic strain of influenza," said Mr Mike Ryan, head of WHO's global epidemic response network. "We have a strain of influenza with the potential to pick up human genes and we're nowhere close to declaring a pandemic."
Neither a human nor a chicken source could be ruled out in the Vietnam case, but even if the women did catch the disease from a family member, limited human-to-human transmission of the virus is not the real danger.
What experts fear is the virus mutating into a form that passes easily between people - a pandemic strain that is a hybrid of the bird virus and a normal human influenza variety.
Ten countries are battling bird flu and at least 45 million chickens have been slaughtered across the region to stop its spread. Nations that have seen their poultry industries ravaged by the epidemic continued to struggle with the economic fallout today.
But fears that avian influenza had spread to Europe subsided after doctors said a German tourist who came down with flu-like symptoms after visiting Thailand was most likely free of the disease.
AP