The first probable case of one person infecting another with bird flu may be a one-off event with no new threat to human health, the World Health Organization (WHO) said.
"This could be just a dead end. That's what it looks like now. But we really need to finish the studies we have ongoing. We'll know more this week," WHO spokesman Mr Dick Thompson said of the case announced by Thailand today.
Thailand said earlier a woman (26) who died on September 20th had probably caught the H5N1 birdflu virus while looking after her 11-year-old daughter in hospital.
But Mr Thompson said that even if human-to-human transmission were confirmed, early indications were that the virus, which originates in birds, did not have a robust mechanism for jumping from one person to another.
Epidemiological studies to determine whether there had been any other cases of human-to-human transmission in Thailand should be completed by the end of the week, he added.
In its statement, the Thai government also said the case was an isolated incident that posed little risk to the greater population. No health workers at the hospital had fallen ill.
The mother's death took to ten the number of Thais killed by the H5N1 virus. In Vietnam, 20 people have died of the disease