The highly pathogenic avian influenza virus has been detected in samples from a duck farm in Tiszadob, in north-eastern Hungary, the national food safety authority (Nébih) said on Wednesday. Under instructions from the authority, some 51,000 birds at the farm will be culled, while a protective zone within a 3km radius around the farm has been established. Animals within a 10 km radius of the farm will be observed, Nébih said. The authority has also launched an investigation as to the origin of the H5N1 virus detected on the farm. It noted that the low pathogenic H5N2 virus had earlier been detected in southern Hungary.