Laboratory tests in Vietnam have confirmed the patient had contracted the H5N1 virus, bringing to seven the number of human infections so far this year and the Southeast Asian country's fourth death from bird flu in 2007.

The teenager developed a fever and received preliminary treatment in Thanh Hoa province before being rushed to Hanoi.

The World Health Organisation (WHO) has not confirmed the latest infection from bird flu, which killed a 22-year-old pregnant woman from northern Vietnam on July 27.

The poultry virus has killed 46 of the 100 confirmed cases in Vietnam since late 2003, including the latest death.

Globally, the H5N1 virus has killed 192 people out of 319 known cases, according to a WHO tally. Hundreds of millions of birds have died or been slaughtered.

The H5N1 virus remains mainly a virus of birds, but experts fear it could mutate into a form easily transmitted from person to person and sweep the world, killing millions.

(c) Reuters 2007. All rights reserved. Republication or redistribution of Reuters content, including by caching, framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.

07Aug07 17:38 GMT Source RTRS Reuters News Categories: ASIA EMRG FOD HEA IDS/TEXT INTEREST/ABN INTEREST/AFA INTEREST/C INTEREST/CSA INTEREST/DNP INTEREST/G INTEREST/GNS INTEREST/GRO INTEREST/LBY INTEREST/MTL INTEREST/PCM INTEREST/PGE INTEREST/RBN INTEREST/REULB INTEREST/RNP INTEREST/RWS INTEREST/RWSA INTEREST/SNI INTEREST/SNS INTEREST/SOF INTEREST/SXNA LIF LIV PKG/RTRWD VN MST/B/LIF MST/B/SPT MST/G/ENV MST/G/FDA MST/I MST/I/AGR MST/I/CSV MST/I/DRG MST/I/FOD MST/I/HEA MST/I/OFP MST/L/EN MST/N MST/N/LIV MST/R/ASI MST/R/SHA MST/R/STM MST/R/VN TGT/RON

REUTERS

Rare Yangtze River Dolphin Probably Extinct - Study [HDMKHXP]

(Embargoed for release on Tuesday Aug 7 at 2301 GMT)

By Michael Kahn

LONDON - The long-threatened Yangtze River dolphin in China is probably extinct, according to an international team of researchers who said this would mark the first whale or dolphin to be wiped out due to human activity.

The freshwater dolphin, or baiji, was last spotted several years ago and an intensive six-week search in late 2006 failed to find any evidence that one of the rarest species on earth survives, said Samuel Turvey, a conservation biologist, at the Zoological Society of London, who took part in the search.

He said the dolphin's demise -- which resulted from overfishing, pollution and lack of intervention -- might serve as a cautionary tale and should spur governments and scientists to act to save other species verging on extinction.

"Ours is the first scientific study which didn't find any," he said in a telephone interview. "Even if there are a few left we can't find them and we can't do anything to stop their extinction."

The team, which published its findings in the Journal of the Royal Society Biology Letters on Wednesday, included researchers from the United States, Britain, Japan and China. The survey was also authorized by the Chinese government, Turvey said.

The last confirmed baiji sighting was 2002, although there have been a handful of unconfirmed sightings since then. The last baiji in captivity died in 2002, Turvey said.

During the six-week search, the team carried out both visual and acoustic surveys and used two boats to twice cover the dolphin's 1,669 kilometre range stretching from the city of Yichang just downstream from the Three Gorges dam to Shanghai.