Poland has detected its first case of H5 bird flu after two swans were found dead on the bank of the River Vistula in the northern city of Torun, government sources said.
"Initial tests confirmed that it is the H5 virus. We don't know yet, however, if it is the deadly (H5N1) kind.
More tests will be done in Poland and abroad," a senior official familiar with the test results told Reuters.
Another government source confirmed the information. Private news channel TVN24 also said the swans were infected with the H5 virus.
"Samples from the two swans were found on Saturday afternoon and were immediately dispatched to the Pulawy test centre. The samples today were put on the first plane to London," Lech Kubera, spokesman for the provincial crisis-control centre in Torun said.
The preliminary tests for bird flu are routinely conducted in Poland's veterinary research institute in the city of Pulawy. If the presence of a bird flu virus is confirmed, special tests for the H5H1 strain are carried out in Britain.
The pathogenic H5N1 avian influenza virus has spread from Asia to Europe and Africa, infecting almost 200 people since late 2003 and killing at least 93 of them.
Two hundred million birds across Asia, parts of the Middle East, Europe and Africa have died of the virus or been culled.
Scientists fear that if the virus acquires the ability to pass easily from person to person, it could cause a pandemic that would kill millions.