Bird flu has arrived in Germany. After watching with trepidation as the virus approached from Europe's south-east, four dead swams were found last week on the German Baltic Sea island of Rügen. On Tuesday, the head of the Robert Koch Institute --Germany's main disease control center -- confirmed the birds had died from the H5N1 virus, which can be dangerous for humans as well.

"We personally as experts don't have any more doubts," Prof. Reinhard Kurth, the president of the Robert Koch Institute, told German ZDF television. He suggested Germans avoid contact with birds, but Kurth also stressed that there was no immediate concern for the general public. "First stay calm, don't panic. There's no reason for it."

Despite the arrival of the H5N1 virus in Germany, officials are so far not overly concerned about poultry in the country. Cautionary measures are being taken, though. Domestic fowl within three kilometers of where the dead swans were found will undergo tests for the virus and, as of Friday, all domestic fowl must be kept indoors to protect against infection from migratory birds. On Monday, before the presence of H5N1 had been confirmed, German Agriculture Minister Horst Seehofer had moved up the date for moving poultry indoors from the originally planned March 1 to Feb. 20.

The first cases of bird flu in Germany come after confirmations of the virus in several European Union countries. Swans in southern Italy have also been found infected with H5N1 and other cases have recently surfaced in Greece and Austria.

H5N1 also has occurred in birds in Asia, Africa and the Middle East. The strain of the virus has killed at least 91 people in Asia and Turkey since 2003, according to the World Health Organization. Almost all the human deaths have been linked to contact with infected poultry, but experts fear H5N1 could mutate into a form that spreads easily among people, possibly starting a human flu pandemic.