A woman who died earlier this month of bird flu (search) probably got the disease from her daughter, a Thai official said Tuesday, increasing concern the case is the first known human-to-human transmission of the disease.
The 26-year-old woman, Pranee Thongchan, died on Sept. 20, and is confirmed to have contracted the deadly H5N1 virus (search), Charal Trinwuthipong, director general of the Disease Control Department, told reporters. She is the 10th confirmed human fatality from the virus in Thailand this year.
Pranee's 11-year-old daughter Sakuntala, who passed away Sept. 12, is believed to have died of avian influenza she got from chickens in her house. But it could not be confirmed because her body was cremated before tests could be done.
Pranee had no contact with the chickens but did have a "very close and face-to-face exposure" to her daughter while tending to her in hospital, a Public Health Ministry statement said.
"We have all agreed that a probable human-to-human transmission has occurred," Dr. Kumara Rai, the acting Thailand representative of the World Health Organization (search), told The Associated Press.
The development "should be viewed by the international community with concern," said Scott Dowell, director of the International Emerging Infections Program. The "documentation of human-to-human transmission in this situation is better than it has been in previous cases," Dowell said.
Human to human transmission has been suspected in the past in some cases in Vietnam and Hong Kong, but was never confirmed.
Scientists fear a global pandemic if it turns out that the virus has mutated to mix with the human influenza virus and can jump from one human to another.
Pranee's sister, Pranom, 32, was also confirmed Monday as suffering from bird flu, and is now in hospital in an isolation ward. The two sisters had been tending to Sakuntala in hospital before her death.
Pranee is the second Thai to be a confirmed fatal victim of the disease since it resurfaced in July. Eight others died in the first round of the avian influenza since January. Another 19 people have died in Vietnam and tens of millions of chickens killed or culled in many parts of Asia.
The Thai government sought to play down fears of human-to-human transmission, saying it appeared to be a one-off case.
"There is no evidence to suggest that the virus has mutated or re-assorted. This probable human-to-human transmission of avian influenza was related to a single index case and was limited within a family."
No other members of the village where Sakuntala lived, or health care workers in the hospitals where she and her mother were admitted are so far found to be ill, the health ministry statement said.
It said the improbability of the virus mutating was confirmed by a meeting of experts Monday of Thailand's Mahidol University, the World Health Organization, the U.S. Centers for Disease Control and Prevention (search), and communicable disease control advisers to the Public Health Ministry.
"Although the finding of probable human-to-human transmission is clearly of concern, there is currently no evidence of ongoing chains of transmission or risk to persons outside the affected provinces," it said.
On Monday, a joint statement by two U.N. agencies said: "The avian influenza epidemic in Asia is a 'crisis of global importance' and will continue to demand the attention of the international community for some time to come.
More research is urgently needed as the role of wildlife, domestic ducks and pigs in transmitting the virus among animals is still not fully understood, said the statement by the Food and Agriculture Organization and the World Organization for Animal Health.