Birds from East African neighbours Kenya and Ethiopia were being tested for the H5N1 bird flu strain, which can also infect humans, as the virus extends its rapid spread around the globe.
The spread of the infection to domestic poultry in other European and neighbouring countries is highly likely and may even be made worse by the arrival in Europe of possibly infected birds from Africa and the Middle East next spring, the World Organisation for Animal Health (OIE) said.
France has already confirmed the first outbreak of the H5N1 virus at a farm in the European Union. The news has prompted some countries to ban French poultry, and fears over bird flu are hitting consumption in a number of countries.
The U.N. Food and Agriculture Organisation (FAO) cut its estimate for global poultry consumption by around 3 million tonnes to 81.8 million tonnes.
Cases in wild birds have appeared across Europe, the latest in Sweden which said on Tuesday it had detected its first cases of an aggressive form of bird flu though it was not yet confirmed as the deadly H5N1 strain in two wild ducks.
The virus has been found in wild birds in the region of Oskarshamn (on Swedens southeast coast), the Agriculture Ministry said in a statement.
The ministry said it appeared to be the same strain as detected in Russia and China, both of which have been hit by outbreaks of H5N1, but that was still to be confirmed.
The H5N1 virus has been detected in around 20 new countries over the past month alone, crossing into Europe and Africa. The virus is endemic in birds across parts of Asia.
It has led to the culling or deaths of some 200 million birds since late 2003.