An outbreak of granulomatous inflammation associated with Francisella noatunensis subsp. orientalis in farmed tilapia (Oreochromis niloticus × O. aureus) in China

• Published in: Chinese journal of oceanology and limnology Vol. 34; no. 3; pp. 460 - 466
• Main Authors: Lin, Qiang, Li, Ningqiu, Fu, Xiaozhe, Hu, Qiandong, Chang, Ouqin, Liu, Lihui, Zhang, Defeng, Wang, Guangjun, San, Guibao, Wu, Shuqin
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.05.2016; Springer Nature B.V
• Subjects: Aquaculture; Bacteria; Biology; Brackish; Earth and Environmental Science; Earth Sciences; Fish; Francisella; Freshwater fishes; Granulomas; Heart; Inflammation; Kidneys; Marine; Marine fishes; Oceanography; Oreochromis niloticus; Pathogens; Ribonucleic acid; RNA; rRNA 16S; Spleen; Tilapia; Water purification; Whitefish; China; China, People's Rep., Guangdong Prov., Guangzhou; tilapia; granulomatous; 16s rRNA
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-016-4311-2

In 2013, a novel disease was detected in tilapia ( Oreochromis niloticus × O. aureus ) in Guangzhou, South China. To identify the causative pathogen, we conducted histological examination, bacteria isolation, and purification, and sequenced the 16S rRNA gene of isolates. Infected fish had a large number of white granulomas in the kidney, liver, heart, and spleen. The head kidney and spleen were markedly swollen. A bacterium strain designated as gz201301 was recovered from the spleen of infected tilapia. The 16S rRNA sequence of gz201301 revealed that it was highly similar to F. noatunensis subsp. orientalis . This is the first report of a Francisella -like infection in farmed tilapia in China.