A second Turkish teenager from the same family died from bird flu today in the first human cases of the disease outside China and southeast Asia.
Although not definitively confirmed as the H5N1 strain of bird flu, the deaths appear to mark a major shift westwards to the edge of Europe of a disease which has killed 74 people in eastern Asia since 2003.
The dead children came from a remote rural district near the Armenian border where people live, as in the affected areas of the Far East, in close proximity with livestock and poultry, which they mostly raise for their own consumption.
The 15-year-old girl died in hospital at around 6:30 a.m. local time. Her 14-year-old brother died at the weekend, and newspapers printed photos of relatives burying him on Wednesday in a deep grave covered with lime as a precaution.
Turkish officials have said the cause of death was the H5N1 strain of bird flu. The bird flu diagnosis was made by two laboratories in Turkey after initial tests were negative.
"We are pretty confident that unfortunately it is a human case of H5N1," Guenael Rodier, special adviser on communicable diseases at the WHO's European office, told Reuters by telephone from Copenhagen.
Although more tests would be needed to be certain of the virus, all evidence pointed to it being H5N1, he added.
Another patient from the family is in a particularly critical condition.
The H5N1 virus remains hard for people to catch, but there are fears it could mutate into a form easily transmitted among humans. Experts say a pandemic among humans could kill millions around the globe and cause massive economic losses.
A UN official said the news from Turkey was disturbing but not yet a cause for panic.