A 14-year-old Turkish boy who died at the weekend was not killed by bird flu, the country's health ministry says.
Officials have been taking precautions in Turkey
The boy was initially feared to have died from the same virus that has killed more than 70 people in Asia.
Three of his siblings, who were also taken ill, have also tested negative for the disease, while tests on two others have still not been returned.
It is still not clear what did kill Mehmet Ali Kocyigit, officials said.
"The disease is not caused by bird flu or any other flu virus," Turan Buzgan, a health ministry official, said.
The hospital where the boy was on life support before he died said he had pneumonia, according to CNN-Turk television, but this was not confirmed by the ministry.
The dead victim had been admitted to hospital on Saturday, along with his brother and two sisters, aged from six to 15, after they developed high fever, coughing, and bleeding in their throats.
The children lived on a poultry farm, where some of the birds had become sick. They reportedly became ill after eating one of them.
The eldest sister was also reported to be in critical condition.
Two other patients, aged five and 35, were also taken to hospital on Sunday, the Anatolia news agency reported.
The H5N1 strain of bird flu - which has infected and killed dozens of people in Asia - has been discovered in bird flocks in Turkey, but no human cases have yet been detected.
Turkey lies on the migration path of wild birds suspected of spreading the flu westwards from Asia.
So far the disease appears only to have infected people who live or work closely with birds, but health experts fear it could mutate and spread among human populations as easily as common influenza.