APHANOMYCES SPECIES ASSOCIATED WITH EPIZOOTIC ULCERATIVE SYNDROME (EUS) IN THE PHILIPPINES AND RED SPOT DISEASE (RSD) IN AUSTRALIA - PRELIMINARY COMPARATIVE-STUDIES

Fungi morphologically consistent with class Oomycetes were recovered o n primary culture from 20 of 22 ulcers on 21 fish with epizootic ulcer ative syndrome (EUS) collected from 5 sites in the Philippines, Eleven primary isolates, and the unifungal cultures derived from them, were identified as Aphanomyces spp.; the remaining 9 primary isolates were lost through contaminant overgrowth. The Aphanomyces isolates were mor phologically and culturally indistinguishable from those reported from red spot disease (RSD) in Australia, Comparison of 4 representative A phanomyces isolates from Australian fish with RSD and 3 representative Aphanomyces isolates from Philippine fish with EUS, using SDS-PAGE (s odium dodecyl sulphate polyacrylamide gel electrophoresis), revealed s imilar peptide banding profiles, indicative of a single Aphanomyces sp ecies. These findings, combined with epizootiological and pathological similarities between EUS and RSD, suggest the 2 syndromes are identic al, and that a single Aphanomyces sp. may be the primary infectious ca use.