A domestic cat in Germany has become the first European Union mammal to die of the deadly H5N1 strain of bird flu.
The cat was found on Germany's Ruegen island
The cat was found dead at the weekend on the Baltic island of Ruegen, where dozens of birds infected with H5N1 have been found.
Further north, Sweden has detected "aggressive" bird flu in two wild ducks and is testing to confirm H5N1.
Meanwhile, vets from 50 countries have been meeting in Paris for a second day to discuss ways to combat the virus.
The H5N1 infection in the German cat was confirmed by officials at the national laboratory, the Friedrich Loeffler Institute, but tests are continuing to determine if it is the exact strain that has been found in birds.
Laboratory chief Thomas Mettenleiter said pet owners on the island should keep cats inside for the time being.
Cats have been known to contract the virus from eating infected birds. Three rare civet cats in Vietnam died of bird flu last August. In October 2004, dozens of tigers died at a private zoo in Thailand after a bird flu outbreak.
There are no recorded cases of cat-to-human infection, but the German finding will raise concerns of further cross-species transmission.
In Sweden, the agriculture ministry said the virus detected in the ducks in the Oskarshamn region, 150 miles (250km) south of Stockholm, was a "highly pathogenic" version of the H5 virus that kills only birds.
The ministry said it suspected it would turn out to be H5N1, which can kill humans.
"This means that we have bird flu in Sweden. It's serious, but not unexpected," Agriculture Minister Ann-Christin Nykvist said.
Further tests are being carried out on the samples at the EU's laboratory in the UK.
At the Paris headquarters of the World Organisation for Animal Health (OIE), chief veterinary officers from Europe, Iran, Kuwait and Azerbaijan have met to discuss how to co-ordinate their response to the spread of the disease.
OIE director-general Bernard Vallat told France's Le Monde newspaper that bird flu was transforming from "epidemic to pandemic".
"With the exception of Australia and New Zealand, which are not hit by bird migrations from affected areas, the rest of the world is directly exposed," he said.
On Tuesday, German government officials said H5N1 had been found in the southern state of Bavaria, the fifth German state to report cases.
And in Romania, samples of domestic fowl found to have the H5 virus were being tested for the H5N1 strain, the agriculture ministry confirmed.
H5N1 does not yet pose a large-scale threat to humans. However, experts fear the virus could mutate and trigger a flu pandemic, potentially putting millions of human lives at risk.