The deadly bird flu virus H5N1 has spread to German poultry, federal health authorities said Friday according to dpa. Federal animal-health scientists confirmed that a domestic goose died of the virus, which suddenly reappeared last month in swans and grebes in the east of Germany at the same time as an outbreak in the Czech Republic. The virus is fatal to humans, but can only be transmitted from birds to people. Scientists worry that it may mutate and become infectious between people, causing a worldwide pandemic. Officials in Thuringia state said the householder's other three geese and five ducks had been destroyed and a quarantine zone been declared around the small town of Wickersdorf. The only other time the virus hit German poultry was a year ago, on April 5, 2006, when a goose farm near Leipzig was infected. This year, poultry have caught the disease in Hungary, the Czech Republic and Britain. In the wild in Germany, the virus has so far killed 153 grebes on a lake at Kelbra in Saxony-Anhalt state, the animal health laboratory said after tests. It earlier killed swans in Nuremberg.