VIRUSES ASSOCIATED WITH THE EPIZOOTIC ULCERATIVE SYNDROME (EUS) OF FISH IN SOUTH-EAST ASIA

A number of birnaviruses, rhabdoviruses and a reovirus have been isola ted from occasional fish affected with the epizootic ulcerative syndro me (EUS) in the past decade. The heterogeneous nature of these isolate s, together with a low and inconsistent level of recovery from disease d specimens, suggests that these viruses may only represent adventitio us infections unrelated to outbreaks of EUS. Furthermore, experimental induction of the condition by direct exposure to cell culture isolate d viruses has not been achieved. The significance, if any, of C-type r etroviruses identified in cell cultures derived from EUS-susceptible f ish species is not known.