The World Health Organization, WHO, says a team of international experts is investigating an outbreak of avian flu in a remote area of Turkey, where three children from one family have died and 25 people are being treated for possible bird flu symptoms.
A WHO spokeswoman, Fadela Chaib, says the U.N. health agency is quite worried because of the spread of the virus beyond East Asia.
"It is the first time we have avian flu outside East Asia," she said. "We were worried about five countries in Asia, and now we have one country in Europe, Turkey. And, we are also worried about these clusters of cases. You know that the nightmare will be, if we have an epidemic. It means, if avian flu is transmitted from a person to a person."
Ms. Chaib says there is no indication of human-to-human transmission of the virus among the children who died in Turkey. Turkish officials suspect the youngsters became sick because of close contact with chickens that were kept at home.
Officials at the World Health Organization said Thursday preliminary tests indicate the first two siblings died of the H5N1 strain of the virus.
Since January 2004, 142 human cases of H5N1 infections, including 74 deaths, have been reported in Viet Nam, Thailand, Cambodia, Indonesia and China.
Scientists fear that the deadly H5N1 virus in poultry could mutate into a form that could easily spread among humans. They warn this could trigger a global pandemic with the potential for killing millions of people.
The five WHO specialists investigating the outbreak in Turkey include a virologist, epidemiologists, an infection control specialist and a public health official. They will work with the Turkish Health Ministry.
Ms. Chaib says the experts will investigate the source of the virus and how it was transmitted to the children.
"One of the recommendations is to proceed quickly to the culling of all the chickens in the neighboring farms or villages, in order to try to break the chain of transmission between animals and humans," she added.
Last year, the virus was detected among wild birds that migrated to Turkey and parts of southeast Europe. These birds are believed to have infected domestic poultry.