Attention to viral infections and pathology previously focussed on diseases of economically important fish. In recent years, however, much new information on molecular virology and oncogenicity derives from viruses occurring in amphibians. New insights into the field of zoonosis were gained by studies of lower vertebrates serving as intermediate hosts in multiple human infections. Certain viruses, e.g. the influenza virus or calicivirus, seem capable of bridging species lines and even the land – sea interface. Global developments in aquaculture are indicated in influenza pandemics. These proceedings present research findings on viruses of fish, amphibians and reptiles, including defence mechanisms, zoonoses, evolutionary considerations and diagnostic approaches.