Myxosporean Emaciation Disease of Cultured Red Sea Bream Pagrus major and Spotted Knifejaw Oplegnathus punctatus

Abstract

Myxosporean emaciation disease of cultured red sea bream Pagrus major and spotted knifejaw Oplegnathus punctatus has recently occurred in Japan. Morphological features and molecular analysis of SSU rDNA indicated that myxozoans from the intestine of affected fishes were identified as Enteromyxum leei, one of the causative organisms of the emaciation disease of tiger puffer Takifugu rubripes. A one-year periodic examination of E. leei infection in cultured red sea bream revealed that cumulative mortalities reached about 10% during the first summer, but surviving fish were not infected in the following year. Experimental transmission of E. leei from infected tiger puffer to naive red sea bream was achieved by both cohabitation with infected fish and exposure to effluent from a tank containing infected fish. This study suggests that fish-to-fish transmission occurs among different fish species in culture fields.