Paris ? The deadly H5N1 bird flu virus has killed 15 wild swans in southeastern France, agriculture officials said Sunday, raising fears the lethal strain could spread in the European Union’s leading producer of poultry.

The news of the dead swans came a day after French authorities confirmed that a nearby turkey farm of more than 11,000 birds had been contaminated – the European Union’s first outbreak of deadly bird flu in commercial poultry.

The dead swans were found around the numerous ponds that dot the southeast area.

Switzerland, meanwhile, reported Sunday that an H5 subtype of bird flu has been found in a dead duck in Geneva, and tests were pending to determine if it was the H5N1 strain, which hasn’t yet been reported in the country.

The lethal H5N1 bird flu strain has spread from Asia to at least 10 European countries and Africa, and scientists fear it could mutate into a form that is easily transmitted between humans, sparking a pandemic.

No human cases have been reported anywhere in Europe.