Abstract

Histopathological investigations carried out between 1992 and 1994 on a large number of fresh and brackishwater fish of Karnataka, India, have confirmed that the ulcerative syndrome sweeping through Karnataka since 1991 is the devastating epizootic ulcerative syndrome (EUS). The 2 key diagnostic features of EUS, namely, oomycete involvement and proliferative mycotic granulomatosis, have been consistently demonstrated in all affected fresh and brackishwater fishes of Karnataka. Interestingly, Indian major carps and tilapia present in these affected water bodies were refractory to EUS. Mycotic granulomatosis and seasonality have been identified as the key features of this syndrome.