Bacterial enteritis of cultured flounder Paralichthys olivaceus larvae

Chokan-hakudaku-sho' is a devastating disease of larval Japanese flounder Paralichthys olivaceus caused by a bacterium tentatively named Vibrio sp.INFL after the disease it causes: intestinal necrosis of flounder larvae.The disease was reproduced in 16 to 27-d-old flounder larvae by oral challenge with Vibrio sp.INFL was incorporated into brine shrimp Arternia salina nauplii or rotifers Brachionus plicatilis, but not in older fish.Histopathological and electron microscopic examinations revealed that pathogen multiplication and resultant pathological changes occurred only in the intestine.Although pili-like structures were not observed on the cells of the pathogen, an adhesive property was demonstrated on a chinook salmon embryo (CHSE-214) cell line.