Swiss authorities have said that they had discovered four new cases of the broad H5 family of the avian influenza virus in wild ducks. The Federal Veterinary Office said in a statement that that three cases had been detected in the northeastern canton of Thurgau near the German border and another in the nearby canton of Zurich.
Samples from the birds have been sent to the European reference laboratory in Britain to determine whether they had the highly pathogenic H5N1 strain of influenza, it added.
Tests are already under way on other wildfowl found in the region next to Lake Constance over the past week.
A dead duck which was found in the western city of Geneva just over a week ago marked the Alpine country's first case of H5N1, which can also be deadly to humans.
Swiss authorities said they expected to find more cases of avian influenza in wildfowl over the coming days.
