A 26-year-old Thai woman who died of acute pneumonia on 20 September was a 鈥減robable鈥� case of human-to-human transmission of the H5N1 bird flu virus, the Thai Ministry of Public Health confirmed on Tuesday.
All 40 previously confirmed human cases of the virus since 2003 were apparently caught from sick birds. But the World Health Organization fears the virus could cause a lethal pandemic if it gains the ability to pass easily from person to person.
The Thai ministry鈥檚 statement stressed that the probable case of human-to-human transmission followed prolonged, close contact between the woman and her sick daughter, who also died from bird flu. The virus did not show an ability to spread easily, as human flu does, which is required for a pandemic.
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But research on the virus鈥檚 recent evolution shows it has become steadily better at replicating in mammals in the past few years. It may now be learning to spread between them.
Destroying chickens
Eleven-year-old Sakuntala Premphasri fell ill with flu symptoms on 2 September, in a village in the northern Thai province of Kamphaeng Phet. She lived there with her aunt and a few days earlier had helped to destroy some dead chickens.
Her mother, Pranee Thongchan, who was working near Bangkok, came home to care for her daughter in hospital. But the girl died on 12 September. Pranee went back to Bangkok, also developed flu, and died eight days later.
Thai officials have now confirmed that her lungs contained H5 flu virus. The Thai ministry said it could not rule out her having somehow picked up the virus 鈥渋n the environment鈥� while in Kamphaeng Phet, but says it is 鈥減robable鈥� that she got the virus from her daughter. Pranee had no known contact with sick birds.
The girl鈥檚 aunt got sick a day after Pranee, and more than two weeks after destroying the sick birds. This is much longer than flu鈥檚 incubation period, so she too might have acquired the virus from her relatives rather than the birds. She is in hospital, and confirmed to have H5.
Suspected cases
The aunt鈥檚 three-year-old son has now recovered from suspected H5 flu, but nine more people in the province are suspected cases, including a 13-year-old who has died.
In a joint statement on Monday, the UN Food and Agriculture Organization and the World Organization for Animal Health called the avian influenza epidemic in Asia 鈥渁 crisis of global importance鈥�.
They stated that 鈥渞ecent outbreaks in China, Thailand, Vietnam, Cambodia, and Malaysia show that the virus continues to circulate in the region, and will probably not be eradicated in the near future鈥�.
The two agencies called for more research into how wildlife, domestic ducks and pigs help spread the virus, as 鈥渁 permanent threat to animal and human health continues to exist鈥�.