Baculoviral mid-gut gland necrosis (BMN) of kuruma shrimp (Penaeus japonicus) larvae in Japanese intensive culture systems

摘要: In many shrimp farms in the Kyushu and Chugoku areas of Japan, so-called mid-gut gland cloudy disease kuruma larvae(Penaeus japonicus) has occurred since 1971. The pathological changes associated with this baculoviral necrosis (BMN) are extensive cellular necrosis, collapse cells, nuclear hypertrophy finally karyorrhexis. Electron microscopic examination revealed presence virions virogenic stages affected nuclei. Average length diameter detected was 310 72 nm, respectively; nucleocapsids were 250 nm size. Virions enclosing 2 within a single envelope rarely found. spirally arranged capsomeres at an angle 37 to 38° horizontal line meeting right angles long axis virion. Infectivity trials resulted high mortality healthy mysis juveniles (2nd post-larval stage). Juveniles 9th stage showed no mortality, although they could be infected easily by agent. Hypertrophied nuclei squashed stained preparations cells can considered reliable presumptive diagnostic character, fluorescent antibody staining employed confirm diagnosis BMN.