Soto Esteban, Shahin Khalid, Talhami J Johnny, Griffin Matt J, Adams Alexandra, Ramírez-Paredes J Gustavo
Department of Medicine and Epidemiology, University of California, School of Veterinary Medicine, Davis, CA 95616, USA.
Dis Aquat Organ. 2019 Feb 28;133(2):141-145. doi: 10.3354/dao03333.
Francisella noatunensis subsp. orientalis (Fno) is a Gram-negative, pleomorphic, facultative intracellular bacterial pathogen affecting a variety of cultured and wild fish species. Outbreaks of piscine francisellosis in warmwater fish have been documented worldwide; however, reports of Fno from Central America have been limited to a single documented outbreak in cultured tilapia in Costa Rica in 2007. From 2015 to 2017, Fno was consistently recovered from disease outbreaks in Nile tilapia Oreochromis niloticus cultivated in floating cages in Lake Yojoa, Honduras. Mortality rates during these outbreaks ranged from 50 to 85%. Fno was isolated by aerobic culture on selective media and identity confirmed by Fno-specific PCR. Repetitive extragenic palindromic PCR analysis revealed that the case isolates were genetically homogeneous with archived strains recovered from epizootics in cultured tilapia from Costa Rica and Mexico, suggesting the same strain of Fno was responsible for these otherwise unrelated fish kills. The current study provides only the second report of Fno in Central America and characterizes the first Fno outbreak in cultured fish in Honduras.
东方诺卡氏弗朗西斯菌（Fno）是一种革兰氏阴性、多形性、兼性细胞内细菌病原体，可感染多种养殖和野生鱼类。全球范围内均有温水鱼类感染诺卡氏菌病的爆发记录；然而，中美洲关于Fno的报告仅限于2007年在哥斯达黎加养殖罗非鱼中记录的一次爆发。2015年至2017年期间，在洪都拉斯特约阿湖网箱养殖的尼罗罗非鱼疾病爆发中持续检测到Fno。这些疫情期间的死亡率在50%至85%之间。通过在选择性培养基上进行需氧培养分离出Fno，并通过Fno特异性PCR确认其身份。重复外显子回文PCR分析表明，病例分离株与从哥斯达黎加和墨西哥养殖罗非鱼疫情中回收的存档菌株在基因上具有同质性，这表明同一株Fno导致了这些原本不相关的鱼类死亡。本研究是中美洲关于Fno的第二篇报告，也是洪都拉斯养殖鱼类中首次Fno疫情的特征描述。
