Authorities in Germany have started taking precautionary measures following confirmation that two swans died from the H5N1 strain of bird flu, the first such cases in the country.
A 10km surveillance zone has been set up around the Baltic Sea island of Ruegen where the swans were found.
And a ban on keeping domestic fowl out of doors have been brought forward to take effect on Friday.
Most European countries now have similar bans, or are in the process of introducing them.
H5N1 has also been found in dead swans in Austria, Italy and
Greece.
Tests on dead swans found in Croatia, Hungary and Slovenia have confirmed that they carried a virus of the H5 group, of which H5N1 is a subtype, and further tests are being carried out to pinpoint the identity.
Denmark is carrying out tests on four dead swans and two other birds.
The disease has been confirmed in other bird species in Romania, Turkey, Russia and Ukraine, but the only human infections in the west so far have been in Turkey.
There have been twelve cases there, four of whom have died.
