Assessing the accuracy of a polymerase chain reaction test for Ichthyophonus hoferi in Yukon River Chinook salmon Oncorhynchus tshawytscha

Whipps, Christopher M.; Burton, Tamara; Watral, Virginia; St‐Hilaire, Sophie; Kent, Michael L.

doi:10.3354/dao068141

Cited by 20 publications

(36 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A second subsample of cardiac muscle was placed in 95% ethanol and shipped to Purdue University, West Lafayette, IN, for molecular confirmation of infection. The presence of Ichthyophonus 18S rDNA was evaluated using polymerase chain reaction (PCR) following the procedure described by Whipps et al (2006). While molecular confirmation positively identifies Ichthyophonus, the culture method determines whether the parasite is viable in the host.…”

Section: Sample Collectionmentioning

confidence: 99%

“…The tissue was then incubated at 14°C and examined daily for Ichthyophonus schizonts (Fig. 1B) to confirm clinical infection with Ichthyophonus at the State University of New York, Syracuse, NY (Whipps et al 2006). A second subsample of cardiac muscle was placed in 95% ethanol and shipped to Purdue University, West Lafayette, IN, for molecular confirmation of infection.…”

Section: Sample Collectionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Ichthyophonus on blood plasma chemistry of spawning Chinook salmon and their resulting offspring in a Yukon River tributary

Floyd-Rump

Horstmann-Dehn²,

Atkinson³

et al. 2017

Dis. Aquat. Org.

View full text Add to dashboard Cite

Ichthyophonus is a protozoan parasite of Alaska Chinook salmon Oncorhynchus tshawytscha. In this study, we determined whether spawning Chinook salmon in the Yukon River drainage exhibited a measurable stress response (i.e. elevated plasma cortisol concentrations) and detectable changes in selected blood plasma chemistry parameters when infected with Ichthyophonus. The resulting alevin were also analyzed for any differences in blood plasma chemistry caused by parental infection with Ichthyophonus. In 2010, spawning adult Chinook salmon were collected from the Salcha River, Alaska, USA, and the prevalence of Ichthyophonus in these fish was 7.8, 6.3, and 8.3%, respectively. Fish with no clinical signs of Ichthyophonus and Ichthyophonus-positive parents were cross-fertilized to investigate potential second-generation effects as a result of Ichthyophonus infection. We found no significant difference in cortisol concentrations in blood plasma between Ichthyophonus-positive and -negative adults or between alevin from Ichthyophonus-positive and -negative parents. There were no significant differences in blood plasma parameters (e.g. alanine aminotransferase, creatine kinase, glucose) of Ichthyophonus-negative and -positive adults, with the exception of aspartate aminotransferase, which was significantly higher in plasma of Ichthyophonus-negative adults. All clinical chemistry parameters for alevin resulting from both Ichthyophonus-negative and -positive parents were not significantly different. Based on this study, which has a limited sample size and low prevalence of Ichthyophonus, offspring of Chinook salmon appear to suffer no disadvantage as a result of Ichthyophonus infection in their parents on the Salcha River.KEY WORDS: Oncorhynchus tshawytscha · Protozoan · Parasite · Yukon River · Salcha River · Cortisol concentration · Clinical blood chemistry Resale or republication not permitted without written consent of the publisherDis Aquat Org 122: [223][224][225][226][227][228][229][230][231][232][233][234][235][236] 2017 by up to 50% (JTC 2011(JTC , 2013(JTC , 2014. In 2014, all Chinook salmon harvest, including subsistence, was closed on the Yukon River. In 2015, the run was still below the historical average, but escapement into Canada was met and some subsistence fishing was allowed (ADF&G 2015). While the ultimate cause(s) for the continued run failures of Chinook salmon remain unknown, infectious diseases play a role in some other salmon population declines (Kocan et al. 2004. Disease may be a contributing factor, either due to pathogen-induced mortality, reduced fecundity, or the inability of Chinook salmon to successfully migrate and spawn.Ichthyophonus is a marine-derived protozoan parasite infecting a variety of marine and anadromous fish species, including salmonids (McVicar 1999, Kocan et al. 2004, Tierney & Farrell 2004, Gavryuseva 2007. This parasite was identified in the mid1980s after fishers reported white papules on the heart, liver, and musculature of Chinook salmon returning to spawn...

show abstract

Section: Sample Collectionmentioning

confidence: 99%

Section: Sample Collectionmentioning

confidence: 99%

Effect of Ichthyophonus on blood plasma chemistry of spawning Chinook salmon and their resulting offspring in a Yukon River tributary

Floyd-Rump

Horstmann-Dehn²,

Atkinson³

et al. 2017

Dis. Aquat. Org.

View full text Add to dashboard Cite

show abstract

“…Conventional and quantitative polymerase chain reaction (PCR)‐based confirmation can be effective for confirming moderate to heavy infections (Whipps et al . ; White et al . ), but false‐negative results can occur as the parasite is focally distributed and may not be detected if only a small tissue amount is analysed.…”

Section: Chromogenic In Situ Hybridization Protocol For the Detectionmentioning

confidence: 99%

Detection of Ichthyophonus by chromogenic in situ hybridization

Conway

Purcell

Elliott

et al. 2014

Journal of Fish Diseases

View full text Add to dashboard Cite

“…Even lower sensitivities were reported for somatic muscle. However, Hamazaki et al (2013) dismiss these results and further dismiss the Whipps et al (2006) sensitivity results as an 'anomaly' without providing any supporting evidence.…”

mentioning

confidence: 98%

“…The authors also attempt to dismiss the conclusions of Whipps et al (2006), who concluded that the 'Sensitivity of the [cPCR] test varied depending on the severity of the infection…' (p. 144) and 'the sensitivity of this [cPCR] test when detecting light infection in heart tissue was lower (range between 50 and 100%)…' (p. 144). Even lower sensitivities were reported for somatic muscle.…”

mentioning

confidence: 99%

PCR testing for diagnosis of Ichthyophonus hoferi: Comment on Hamazaki et al. (2013)

LaPatra

Kocan

2013

Dis. Aquat. Org.

View full text Add to dashboard Cite

It is our opinion that Hamazaki et al. (2013; Dis Aquat Org 105:21-25) overstate the usefulness of PCR as a field diagnostic technique and underestimate the accuracy and utility of in vitro explant culture. In order for field diagnostic studies to be meaningful they should accurately and dependably identify the infected individuals within a population, both subclinical and clinical cases. Although explant culture, like most techniques, can miss some infected individuals, 'false positives' are impossible, unlike for cPCR based methodologies.

show abstract

Assessing the accuracy of a polymerase chain reaction test for Ichthyophonus hoferi in Yukon River Chinook salmon Oncorhynchus tshawytscha

Cited by 20 publications

References 17 publications

Effect of Ichthyophonus on blood plasma chemistry of spawning Chinook salmon and their resulting offspring in a Yukon River tributary

Effect of Ichthyophonus on blood plasma chemistry of spawning Chinook salmon and their resulting offspring in a Yukon River tributary

Detection of Ichthyophonus by chromogenic in situ hybridization

PCR testing for diagnosis of Ichthyophonus hoferi: Comment on Hamazaki et al. (2013)

Contact Info

Product

Resources

About