After transporting Asian seabass Lates calcarifer from a fish farm to the Burapha University facilities, they began to die. The affected or moribund fish exhibited abdominal swelling, yellowish decoloration around the anus, darkening of the gills and exophthalmic eyes. The internal signs of the disease included abdominal cavities filled with a cloudy yellow and gelatinous fluid together with liver hemorrhage. Isolated bacteria from several organs were biochemically characterized as Photobacterium damselae subsp. damselae. It was further confirmed by PCR. An infectivity experiment by intraperitoneal injection with an isolate LCA 24907 showed its virulence to Asian seabass with LD50 of 8.1 ¥ 105 CFU/g fish body weight. This is the first report of isolating P. damselae subsp. damselae from Asian seabass.

This study has been supported in part by the Project RTA2005–00028 from INIA (Subprograma Nacional de Recursos y Tecnologías Agrarias en cooperación con las Comunidades Autónomas) from the Spanish government. MM is the recipient of a research contract from INIA (Spanish Ministry of Science and Technology) cofunded by the European Social Funds