Location: Aquatic Animal Health ResearchTitle: Isolation and characterization of Flavobacterium columnare strains infecting fishes inhabiting the Laurentian Great Lakes basin
|FAISAL, MOHAMED - Michigan State University|
|DIAMANKA, A. - Institut Senegalais De Recherches Agricoles|
|LOCH, T.P. - Michigan State University|
|WINTERS, A.D. - Wayne State University|
|TOGUBAYE, B.S. - Institut Senegalais De Recherches Agricoles|
Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2016
Publication Date: 4/10/2017
Citation: Faisal, M., Diamanka, A., Loch, T., Lafrentz, B.R., Winters, A., Garcia, J.C., Togubaye, B. 2017. Isolation and characterization of Flavobacterium columnare strains infecting fishes inhabiting the Laurentian Great Lakes basin. Journal of Fish Diseases. 40:637-648.
Interpretive Summary: Flavobacterium columnare is the causative agent of columnaris disease that infects warm, cool, and cold water fishes of both wild and hatchery origin. In Michigan, flavobacterial fish diseases are one of the most significant problems in hatchery-reared fish stocks. In this manuscript, researchers collected over 300 isolates of F. columnare from wild, feral, and hatchery-propagated fish in the Great Lakes basin. The data and isolates collected were used to determine the prevalence of F. columnare infections in multiple feral salmonid stocks returning to Michigan gamete collection stations, to characterize representative isolates using a molecular method, and to determine the ability of the isolates to cause disease in rainbow trout. The analyses showed that F. columnare infection prevalence varied spatially and temporally, as well as by fish species and gender, with Chinook salmon and females having significantly higher infection prevalence. Molecular characterization of the isolates revealed that all isolates belonged to a single genetic type (genomovar I) and were capable of causing mortality in rainbow trout. Together, these results suggest that F. columnare genomovar I is widespread in the Great Lakes Basin, where its presence can be associated with fish mortality.
Technical Abstract: Flavobacterium columnare, the etiological agent of columnaris disease, causes significant losses in fish worldwide. In this study, F. columnare infection prevalence was assessed in representative Great Lakes fish species. Over 2,000 wild, feral, and hatchery-propagated salmonids, percids, centrarchids, esocids, and cyprinids were examined for systemic F. columnare infections. Logistic regression analyses showed that F. columnare infection prevalence varied temporally and by the sex of the fish, whereby females had significantly higher infection prevalence. A total of 305 isolates of F. columnare were recovered. Amplification of the near complete 16S rRNA gene from 34 representative isolates and subsequent restriction fragment length polymorphism analyses demonstrated that all belonged to F. columnare genomovar I. Phylogenetic analysis of near complete 16S rRNA gene sequences also placed the isolates in genomovar I, but revealed some intra-genomovar heterogeneity. Together, these results suggest that F. columnare genomovar I is widespread in the Great Lakes Basin, where its presence may lead to mortality.