Outbreaks have been reported in Romania and Russia, while China said it had lost thousands of fowl to the killer virus.
Germany has ordered its farmers to keep poultry indoors as a precaution.
Hungary says it has developed a new vaccine that appears to protect humans and animals against the virus.
The UN has warned that the latest reported cases increase the likelihood of the lethal bird flu strain spreading to Africa and the Middle East, along the flight path of migrating birds.
