A dead swan found on the banks of Lake Constance in eastern Switzerland has tested positive for avian flu - the second confirmed case in the small central European country.

The Swiss Federal Veterinary Office said on Wednesday the swan had carried the H5 virus, and further tests were to be carried out in Britain to confirm whether it died of the deadly H5N1 strain.

Meanwhile, the office said a suspected case of avian flu among poultry in Fribourg, near the capital Bern, had turned out to be a false alarm. So far no domestic fowl in Switzerland have tested positive for the disease.

The country's first case of bird flu was announced on Sunday. The federal authorities said a dead duck found near the port of Geneva was infected with H5.

Laboratory tests in Britain have confirmed that the duck was infected with a H5N virus, and further analysis is being carried out to determine whether it was the deadly H5N1 strain that has been spreading across Europe.

Lake Constance lies between Switzerland, Germany and Austria. The German authorities have reported several cases of bird flu around the lake.

According to the Swiss Federal Veterinary Office, protection and observation zones will be set up in both areas affected by bird flu. But it stressed that there was no danger to the local population.

Source: Xinhua