German authorities say they have found bird flu in wild swans in a second German state.

Officials Tuesday confirm that the H5N1 strain killed three swans near the city of Leipzig in eastern Germany.

The virus was found in six swans last week in a pond in Nuremberg, about 200 kilometers to the south. These are Germany's first bird flu cases in more than a year.

Experts are investigating whether the cases are tied to recent bird flu outbreaks in Hungary and the Czech Republic.

Scientists fear the H5N1 bird flu virus could mutate into a strain easily spread by humans and create a global pandemic.

Bird flu has killed 191 people since 1993. Most of the deaths were in Indonesia.