DAO 82:111-118 (2008)  -  DOI: https://doi.org/10.3354/dao01969

Strawberry disease lesions in rainbow trout from southern Idaho are associated with DNA from a Rickettsia-like organism

Sonja J. Lloyd1, Scott E. LaPatra1,2, Kevin R. Snekvik1,3, Sophie St-Hilaire4, Kenneth D. Cain5, Douglas R. Call1,*

1Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040, USA  2Clear Springs Foods Inc., PO Box 712, Buhl, Idaho 83316, USA
3Washington Animal Disease Diagnostic Laboratory, PO Box 647034, Pullman, Washington 99164-7034, USA
4Department of Biological Sciences, Idaho State University, 921 South 8th Avenue, Stop 8007, Pocatello, Idaho 83209-8007, USA
5Department of Fish and Wildlife Resources, University of Idaho, Moscow, Idaho 83844-1136, USA
*Corresponding author. Email:

ABSTRACT: Strawberry disease (SD) in the USA is a skin disorder of unknown etiology that occurs in rainbow trout Oncorhynchus mykiss and is characterized by bright red inflammatory lesions. To identify a candidate bacterial agent responsible for SD, we constructed 16S rDNA libraries from 7 SD lesion samples and 2 apparently healthy skin samples from SD-affected fish. A 16S rDNA sequence highly similar to members of the order Rickettsiales was present in 3 lesion libraries at 1%, 32% and 54% prevalence, but this sequence was not found in either healthy tissue library. Based on phylogenetic analysis, this Rickettsia-like organism (RLO) sequence is most closely related to 16S rDNA sequences of bacteria that may form a novel lineage within the Rickettsiales. We used nested PCR assays to screen 25 SD-affected fish for RLO or Flavobacterium psychrophilum DNA. Sixteen lesion samples were positive for the RLO sequence and 4 of the matched healthy samples were positive resulting in a significant association between SD lesions and presence of RLO DNA. While F. psychrophilum is reportedly associated with ‘cold water strawberry disease’ in the UK, we found no significant association between SD lesions and the presence of F. psychrophilum DNA. The statistical association between SD lesions and presence of RLO DNA is not proof of etiology, but these data suggest that RLO may play a role in SD in southern Idaho, USA.


KEY WORDS: Strawberry disease · Oncorhynchus mykiss · Rickettsia · 16S rDNA library · CWSD · WWSD · RMS


Full text in pdf format
Supplementary appendix 
Cite this article as: Lloyd SJ, LaPatra SE, Snekvik KR, St-Hilaire S, Cain KD, Call DR (2008) Strawberry disease lesions in rainbow trout from southern Idaho are associated with DNA from a Rickettsia-like organism. Dis Aquat Org 82:111-118. https://doi.org/10.3354/dao01969

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