DAO 101:115-122 (2012)  -  DOI: https://doi.org/10.3354/dao02522

Reproducible challenge model to investigate the virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss

B. R. LaFrentz1,*, S. E. LaPatra2, C. A. Shoemaker1, P. H. Klesius1

1United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Aquatic Animal Health Research Unit, 990 Wire Road, Auburn, Alabama 36832-4352, USA
2Clear Springs Foods, Research Division, PO Box 712, Buhl, Idaho 83316, USA

ABSTRACT: Flavobacterium columnare is a Gram-negative bacterium that causes columnaris disease and has significant economic impacts on aquaculture production worldwide. Molecular analyses have demonstrated that there is genetic diversity among F. columnare isolates. A review of the published literature that used restriction fragment length polymorphism analysis of the 16S rRNA gene revealed that all isolates typed from salmonids were Genomovar I. Our objective was to develop a laboratory challenge model for F. columnare in rainbow trout Oncorhynchus mykiss (Walbaum) and use the model to determine the virulence of Genomovar I and II isolates. Six F. columnare isolates were obtained from rainbow trout experiencing losses due to columnaris disease and were determined to be Genomovar I. Three of these were chosen for a preliminary assessment of virulence, and isolate 051-10-S5 was chosen for additional experiments to determine the reproducibility of the waterborne challenge model. In 2 independent experiments, cumulative percent mortalities (CPM) were 49 ± 10% and 50 ± 19%. Challenge of rainbow trout with Genomovar I and II isolates demonstrated a difference in the CPM, with the Genomovar II isolates inducing significantly higher CPM. This reproducible waterborne challenge model for columnaris disease in rainbow trout will be useful to investigate host−pathogen interactions, vaccine development, and other potential control strategies. This research also provides a basis for further defining the molecular diversity and virulence associated with F. columnare genomovars in rainbow trout and other salmonid species.


KEY WORDS: Flavobacterium columnare · Rainbow trout · Genomovar · Columnaris disease · Challenge model


Full text in pdf format 
Cite this article as: LaFrentz BR, LaPatra SE, Shoemaker CA, Klesius PH (2012) Reproducible challenge model to investigate the virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss. Dis Aquat Org 101:115-122. https://doi.org/10.3354/dao02522

Export citation
Mail this link - Contents Mailing Lists - RSS
- -