Four siblings were rushed into hospital in eastern Turkey on Sunday showing symptoms of the flu. The children who are aged between 11 to 15, had eaten chicken in the town of Dogubeyazit, near the Iranian border.
Muhammet Ali Kocyigit, aged 14, was named as the child who has died, reported the NTV and CNN-Turk television stations said.
Doctors said the cause of his death could have been bird flu or an ordinary case of flu complicated by an infection, adding that samples had been sent to Ankara for analysis. "They had a fever, were coughing and bleeding from the mouth," said hospital doctor Huseyin Avni Sahin.
The television reports said two other people with the same symptoms had been admitted to the Van hospital on Sunday. In recent days, two outbreaks of bird flu have been detected in Turkey, the latest last week in the small town of Aralik, less than 100 kilometers (60 miles) from Dogubeyazit.
Birds in the town tested positive for the H5 virus but on Tuesday an official said it was not clear whether any of them carried the deadly H5N1 strain. As a precaution some 750 birds were slaughtered and all sales of poultry have been banned around Aralik which was put under quarantine.
In mid-December nearly 1,200 birds were found dead in the region. Turkey faces a persistent threat from bird flu as it lies on a major migratory flight path.