Mohamad Nurliyana, Mohd Roseli Fauzul Aidil, Azmai Mohammad Noor Amal, Saad Mohd Zamri, Md Yasin Ina Salwany, Zulkiply Nor Amalina, Nasruddin Nurrul Shaqinah
Department of Biology, Faculty of Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
J Aquat Anim Health. 2019 Mar;31(1):88-96. doi: 10.1002/aah.10055. Epub 2019 Jan 28.
In September 2016, a marine fish farm operator in Selangor, Malaysia, reported a disease outbreak affecting juvenile hybrid groupers (Camouflage Grouper Epinephelus polyphekadion × Tiger Grouper E. fuscoguttatus). The average daily mortality was 120 fish, resulting in a cumulative mortality rate of 29% within 10 d. The affected hybrid groupers displayed lethargy, excessive mucus production, rotten fins, congestion of livers and kidneys, and enlargement of spleens. Microscopically, general congestion of the brains and internal organs was evident. Vibrio harveyi and V. alginolyticus were successfully isolated from the diseased fish. The isolated pathogens were found to be sensitive to oxytetracycline and tetracycline, but resistant towards ampicillin and vancomycin. Experimental infections using the isolated V. harveyi (10 CFU/mL), V. alginolyticus (10 CFU/mL), and concurrent infection by V. harveyi (10 CFU/mL) and V. alginolyticus (10 CFU/mL) in juvenile Asian Seabass Lates calcarifer resulted in 60, 100, and 100% mortality, respectively, within 240 h postinfection. The experimentally infected Asian Seabass demonstrated similar clinical signs and histopathological changes as the naturally infected hybrid groupers. However, concurrently infected fish demonstrated severe clinical signs and histopathological changes compared with single infections. These results suggest that both isolates of Vibrio are pathogenic to fish and responsible for the disease outbreak. However, concurrent infection involving V. alginolyticus and V. harveyi leads to a more devastating impact to the cultured fish. This is the first report of concurrent Vibrio infection in cultured marine fish in Malaysia.
2016年9月，马来西亚雪兰莪州的一名海水鱼类养殖场经营者报告，一种疾病爆发，影响了杂交石斑鱼幼鱼（豹纹鳃棘鲈Epinephelus polyphekadion×老虎斑E. fuscoguttatus）。平均每日死亡率为120条鱼，10天内累计死亡率达29%。受影响的杂交石斑鱼表现出嗜睡、黏液分泌过多、鳍腐烂、肝脏和肾脏充血以及脾脏肿大。显微镜下可见脑和内脏普遍充血。从患病鱼中成功分离出哈维氏弧菌和溶藻弧菌。发现分离出的病原体对土霉素和四环素敏感，但对氨苄青霉素和万古霉素耐药。用分离出的哈维氏弧菌（10⁶ CFU/mL）、溶藻弧菌（10⁶ CFU/mL）以及哈维氏弧菌（10⁶ CFU/mL）和溶藻弧菌（10⁶ CFU/mL）同时感染尖吻鲈幼鱼，感染后240小时内死亡率分别为60%、100%和100%。实验感染的尖吻鲈表现出与自然感染杂交石斑鱼相似的临床症状和组织病理学变化。然而，与单一感染相比，同时感染的鱼表现出更严重的临床症状和组织病理学变化。这些结果表明，这两种弧菌分离株对鱼类都具有致病性，是疾病爆发的原因。然而，溶藻弧菌和哈维氏弧菌的同时感染对养殖鱼类造成的影响更大。这是马来西亚养殖海水鱼中弧菌同时感染的首次报告。
