Non-lethal detection of Renibacterium salmoninarum in Greenback Cutthroat Trout Oncorhynchus clarkii stomias comparing mucus, blood, and ovarian fluid samples to kidney tissues

Journal of Aquatic Animal Health
Colorado Parks and Wildlife
By: , and 

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Abstract

Objective

Renibacterium salmoninarum, the causative agent of bacterial kidney disease, poses a major threat to both wild and aquaculture salmonid populations. Traditional detection methods typically involve lethal sampling to collect kidney tissues but are often impractical for species of conservation concern. This study evaluates nonlethal sampling techniques for detecting R. salmoninarum in Greenback Cutthroat Trout Oncorhynchus clarkii stomias by comparing mucus, blood, and ovarian fluid samples to conventional kidney tissue.

Methods

During the 2019 spawning season, we collected samples from 781 adult fish and tested for R. salmoninarum via direct fluorescent antibody test (DFAT) and quantitative polymerase chain reaction (qPCR).

Results

A total of 25 and 256 kidney tissues were positive by DFAT and qPCR, respectively. Of the three nonlethal samples tested, mucus swabs showed the highest percent correlation for detection with positive kidney tissues (DFAT = 47.6%, qPCR = 41.7%). Blood and ovarian fluid samples showed a lower percent correlation with positive kidney tissues (blood: DFAT = 12.0%, qPCR = 1.2%; ovarian fluid: DFAT = 12.5%, qPCR = 21.4%).

Conclusions

Our results suggest that nonlethal mucus swabbing could serve as a practical alternative for monitoring R. salmoninarum, especially in conservation efforts where minimizing fish mortality is critical.

Suggested Citation

Tawni, F.B., Fetherman, E.R., Winkelman, D.L., 2025, Non-lethal detection of Renibacterium salmoninarum in Greenback Cutthroat Trout Oncorhynchus clarkii stomias comparing mucus, blood, and ovarian fluid samples to kidney tissues: Journal of Aquatic Animal Health, v. 37, no. 4, p. 192-198, https://doi.org/10.1093/jahafs/vsaf013.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Non-lethal detection of Renibacterium salmoninarum in Greenback Cutthroat Trout Oncorhynchus clarkii stomias comparing mucus, blood, and ovarian fluid samples to kidney tissues
Series title Journal of Aquatic Animal Health
DOI 10.1093/jahafs/vsaf013
Volume 37
Issue 4
Publication Date September 09, 2025
Year Published 2025
Language English
Publisher Oxford Academic
Contributing office(s) Coop Res Unit Seattle
Description 7 p.
First page 192
Last page 198
Country United States
State Colorado
Other Geospatial Colorado Parks and Wildlife Poudre Rearing Unit
Additional publication details