The virus has been detected in the southeast, north, and center of the country. All of the victims -- two of whom have died -- appear to have had direct contact with infected birds.
A World Health Organization team sent to Turkey to investigate the outbreak said it could be "relatively" easily controlled.
But the leader of the WHO team, Guenael Rodier, said Turkey's neighbors must also be prepared to deal with the disease.
"Any countries in the regions which have situations in the rural areas similar to what we have here in Turkey could obviously have some diseases in animals, and potentially in humans, and that requires [them] to strengthen surveillance systems both for humans and animals and to take all the measures necessary to control diseases in animals," Rodier said.
Turkey's neighbors say they are taking urgent measures to prevent a spread of the disease.
In Russia, President Vladimir Putin ordered the government to prepare a plan of action to fight possible fresh outbreaks of bird flu there.
Earlier, a senior regional official said bird flu has been confirmed in three poultry farms in southern Crimea.
Ukrainian authorities have confirmed 14 outbreaks, but no human cases of the illness have been recorded.
(from agency reports)