WHO downplays human-to-human transmission of bird flu
A 26-year-old woman who died of avian flu eight days ago almost certainly contracted the disease from her daughter in what could be the first documented case of human-to-human transmission of the virus, health officials in Thailand say.
The World Health Organization later played down the report, suggesting that experts have seen such "dead end" transmissions before.
WHO officials said the virus has been seen to jump from one human to another, only to be defeated by the second person's immune system.
Thailand confirmed that Pranee Thongchan, 26, died Sept. 20 after contracting the H5N1 strain of the virus, the 10th person to die from bird flu this year.
"What appears to have happened is a well-documented episode of transmission in a family cluster after prolonged close contact," said Dr. Scott Dowell, of the U.S. Centers for Disease Control.
"It doesn't necessarily tell us anything has changed about the virus or about the way it's transmitted. But those questions will remain under investigation for the next week or two."
Most human cases have been traced to contact with sick birds.
Dr. Kumara Rai from the World Health Organization said the public shouldn't be alarmed because the case was isolated.
"It doesn't pose a significant public health threat. So there's no reason to be panicked," he said.
Officials believe Pranee's 11-year-old daughter, who died Sept. 12, also had contracted the virus. But the case could not be confirmed because her body was cremated before tests could be done.
Pranee's only possible exposure to avian flu came from the hospital as she helped care for her dying daughter.
Pranee didn't live at the family home so she couldn't have been exposed to the sick chickens that are believed to have triggered her daughter's infection.
Officials confirmed that Pranee's 32-year-old sister Pranom had the deadly virus. On Monday, Thai officials said there was no indication that she caught it from another person.
Pranom and her niece were known to have been in contact with chickens.
Doctors are still investigating whether the bird flu virus may have mutated to make human-to-human transmission easier.
But the Thai government has played down such fears.
"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," said a Public Health Ministry statement.