Britain is calling for a Europe-wide ban on the import of wild birds. Brussels is considering the request, which comes after tests showed a parrot which died in UK quarantine had the lethal H5N1 strain of avian flu.
Scientists fear it may mix with a human flu strain and trigger a lethal pandemic.
The parrot, imported from Surinam in South America in September, is believed to have caught the virus from other infected birds while in quarantine.
So far the aggressive strain of the virus has been found in several European countries.
Tests are being carried out on samples from other countries such as Ukraine and Sweden, which has become the latest European country to report a case of bird flu.
A duck found dead west of Stockholm had a mild type of the virus, but not the deadly form that has killed more than sixty people in Asia.
The Balkans have also reported possible cases. In Croatia, a cull of birds is in full swing.
Dead swans found in a pond there are being examined, as are birds from Greece and Macedonia.
The EU meanwhile is to hold a joint meeting later today with the World Health Organisation to discuss ways of tackling the disease.