Conflicts between birds and humans
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    Avian flu

    Wild birds, especially waterfowl, are suspected to be vectors of the highly pathogenic avian flu subtype H5N1. The Swiss Ornithological Institute participates in the monitoring of migratory birds and thereby studies their role in the spread of this virus.


    Avian flu or avian influenza, as the name suggests, is an avian disease. It is highly pathogenic when transmitted to chicken and can lead to large economic losses. Infections of ducks and geese can occur with mild symptoms or asymptomatically, and therefore infections can remain undetected. Avian flu can be lethal for humans: until June 2008 the WHO had reported 234 casualties worldwide. The importance of wild birds in the spread of the avian influenza virus of the subtype H5N1 is still unclear.

    The Swiss Ornithological Institute in Sempach

    • supports the government agencies with its ornithological knowledge,
    • participates in the monitoring of this disease in free-living birds,
    • analyses ring recoveries of waterfowl in order to better understand the origin and migration routes of the species wintering in Switzerland,
    • is involved in the risk assessments made by the Swiss Federal veterinary office.


    Within the framework of the Federal surveillance of wild birds, the Swiss Ornithological Institute collects samples from waterfowl using pharyngeal and cloacal swabs. Waterfowl is caught at Lake Sempach from November to March. During the last three summers, swans had been caught at Lake Constance as part of the research project "Constanze".

    The samples are analyzed in the Institute of Virology and Immunoprophylaxis (IVI) in Mittelhäusern, the national reference centre for this disease.


    The avian influenza A virus of the subtype H5N1 has been reported in poultry and wild birds in Europe, Africa and Asia. It has caused the death of at least 243 humans in Africa and Asia. In Turkey humans have died from this disease, but no casualty has been reported from Europe. It has not reached the Americas, Australia and New Zealand so far.

    In domestic birds, H5N1 can lead to high mortality and high economic losses as a consequence of culling of poultry. A better understanding of the role of free-living birds as vectors of this disease will enable us to effectively prevent infections of domestic poultry by wild birds.


    The Federal Food Safety and Veterinary Office FSVO publishes the result of the surveillance directly.

    Project management

    Lukas Jenni


    Federal Food Safety and Veterinary Office FSVO
    Institute of Virology and Immunoprophylaxis IVI
    Prof. Dr. med. vet. Richard K. Hoop, Institute of Veterinary Bacteriology, University of Zurich
    Josef Hofer, bird ringer, Oberkirch, Lucerne
    Basellandschaftlicher Natur- und Vogelschutzverband BNV
    Dr. Wolfgang Fiedler, Vogelwarte Radolfzell

    Financial support

    This project is conducted on behalf of the Federal Food Safety and Veterinary Office FSVO


    Hofer, J., F. Korner-Nievergelt, P. Korner-Nievergelt, M. Kestenholz & L. Jenni (2006):
    Herkunft und Zugverhalten von in der Schweiz überwinternden oder durchziehenden Tafelenten Aythya ferina.