Mycobacterium salmoniphilum infection in burbot Lota lota

• Published in: Diseases of aquatic organisms Vol. 95; no. 1; pp. 57 - 64
• Main Authors: ADAM ZERIHUN, Mulualem, BERG, Vidar, LYCHE, Jan L, COLQUHOUN, Duncan J, POPPE, Trygve T
• Format: Journal Article
• Language: English
• Published: Oldendorf Inter-Research 24.05.2011
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal aquaculture; Animal productions; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Esocidae; Fish Diseases - microbiology; Fresh Water; Fresh water ecosystems; Fundamental and applied biological sciences. Psychology; Gadiformes; Mycobacterium - classification; Mycobacterium - genetics; Mycobacterium Infections - epidemiology; Mycobacterium Infections - pathology; Mycobacterium Infections - veterinary; Norway - epidemiology; Phylogeny; Synecology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Norway; Mycobacterium; Lota lota; Multi-gene sequencing; Taxonomy; Phylogeny; Mycobacterium salmoniphilum; Burbot; Infection; Freshwater environment; Pathology; Vertebrata; Gene; Mycobacteriales; Pisces; Mycobacteriaceae; Bacteria; Actinomycetes; Mycobacteriosis; Sequencing
• ISSN: 0177-5103; 1616-1580
• DOI: 10.3354/dao02347

Burbot Lota lota sampled from lakes Mjosa and Losna in southeastern Norway between 2005 and 2008 were found to be infected with Mycobacterium salmoniphilum at a culture-positive prevalence of 18.6 and 3.3%, respectively. The condition factor (CF) of mycobacteria-affected fish sampled from Mjøsa in 2008 was lower than the average CF of total sampled fish the same year. Externally visible pathological changes included skin ulceration, petechiae, exopthalmia and cataract. Internally, the infections were associated with capsulated, centrally necrotic granulomas, containing large numbers of acid-fast bacilli, found mainly in the mesenteries, spleen, heart and swim bladder. Mycobacterial isolates recovered on Middlebrook 7H10 agar were confirmed as M. salmoniphilum by phenotypical investigation and by partial sequencing of the 16S rRNA, rpoB and Hsp65genes as well as the internal transcribed spacer (ITS1) locus. This study adds burbot to the list of fish species susceptible to piscine mycobacteriosis and describes M. salmoniphilum infection in a non-salmonid fish for the first time.