BANGKOK (AFP) - Thailand confirmed its tenth death from bird flu and the first probable case of human-to-human infection in an outbreak that has swept Asia this year.
Pranee Krongkaew, 26, died eight days ago and probably caught the disease while caring for her sick 11-year-old daughter in hospital, officials said on Tuesday. The girl also died this month from suspected bird flu.
But officials played down the worst fears of the World Health Organisation (WHO), that the virus could have mutated into a highly contagious form that would trigger a global human flu pandemic.
Thailand's public health ministry said the probable spread between humans had been limited to a single family.
"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 of the affected province," it said in a statement.
"This isolated episode of probable human-to-human transmission would not pose a significant public health threat."
Asia has been hit by two waves of the disease since December last year that have left 29 people dead in Thailand and Vietnam and killed more than 100 million birds across the region.
The first 28 deaths were linked to close contact between infected birds and humans.
While the disease spreads quickly between birds, no human-to-human cases had been confirmed during the Asian outbreak but experts could not rule out the possibility.
The ministry statement said experts believed there was "no evidence to suggest that the virus has mutated or reassorted", a view backed by the United States Centers for Disease Control and Prevention (USCDC).
A mutated bird flu outbreak was blamed for the deaths of as many as 40 million people worldwide in 1918.
USCDC Thailand director Scott Dowell said the probable human-to-human case raised the likelihood that it happened before in three suspected cases in Hong Kong in 1997 -- which did not result in a pandemic -- and one in Vietnam this year.
"This one (the Thai case) is the most closely documented person-to-person transmission but it's likely not to be the first," he said.
Kamara Rai, the WHO's acting representative for Thailand, told reporters there was no need to panic.
"We have all agreed the probable human-to-human transmission has occurred through a direct, face-to-face and long contact," Rai said.
"Even if this limited episode of human-to-human were confirmed, it does not pose a significant public health threat so there is no reason to panic."
The 11-year-old girl lived with her aunt, also confirmed Monday as having bird flu but recovering, in a village in northern Kamphaeng Phet province where a large number of chickens had died from bird flu.
Pranee, from near Bangkok, visited her daughter in hospital. She looked after her until she died and remained in the province until after her cremation. Pranee fell ill after she returned home.
Charal Trinvuthipong, director-general of Thailand's disease control department, said tests could not confirm she had caught the disease from her daughter.
"The lab test found Pranee was confirmed with H5N1 and the question is where she got it from."
He said she visited the house for two days during her visit. "There were some chickens left at the same time, and she also had close contact with her daughter before she died."
Prime Minister Thaksin Shinawatra said the government would bring forward a planned bird flu meeting to Wednesday to discuss measures to combat the disease that has hit 30 of the country's 76 provinces in the latest wave.
Nineteen cases of suspected bird flu in humans remain under investigation in Thailand but dozens more have been cleared of links to the virus.
Two global bodies warned on Monday that the bird flu epidemic was a "crisis of global importance" and the virus was unlikely to be eradicated soon.
The UN Food and Agriculture Organisation and the World Organisation for Animal Health said avian influenza would "continue to demand the attention of the international community for some time to come".