A comparative study of muscle texture and intensity of Kudoa thyrsites infection in farm-reared Atlantic salmon Salmo salar on the Pacific coast of Canada

St‐Hilaire, Sophie; Hill, Michelle; Kent, Michael L.; Whitaker, David; Ribble, Carl

doi:10.3354/dao031221

Cited by 44 publications

(25 citation statements)

References 4 publications

(6 reference statements)

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“…As few as 100 spores could be detected. It has been estimated that a threshold of infection of 20 000 spores per gram of infected muscle tissue is required before post-mortem myoliquefaction occurs (St-Hilaire et al 1997). In our lab-based assay we used 5 µl of spore suspension to spot onto the detection membrane.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Kudoa thyrsites (Myxozoa: Myxosporea) spore antigens using monoclonal antibodies

Chase¹,

Dawson-Coates²,

Haddow³

et al. 2001

Dis. Aquat. Org.

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A method employing Percoll™ gradient centrifugation was developed to purify Kudoa thyrsites spores from somatic muscle tissue of Atlantic salmon Salmo salar. Highly purified spores were then used to immunize inbred BALB/c mice for derivation of hybridomas secreting Kudoaspecific monoclonal antibodies (mAbs). Analysis of mAbs by immunofluorescence microscopy and flow cytometry showed that several were specific for antigens on the surface of K. thyrsites spores whereas other mAbs reacted with polar capsules or with polar filaments of spores of K. thyrsites, K. paniformis and K. crumena. Immunoblots on spore lysates using the surface-binding mAbs showed a broad band of 46 to > 220 kDa, whereas mAbs specific for antigens of polar capsules and polar filaments detected sharper bands of various molecular masses, depending on the Kudoa species. The dominant epitope of the K. thyrsites spore surface antigen was shown to be carbohydrate as determined by its sensitivity to treatment with anhydrous trifluoromethane sulfonic acid and by its resistance to treatment with Proteinase K. Immunofluorescence microscopy using the K. thyrsites-specific mAbs on isolated, intact, permeabilized plasmodia and on thin sections of somatic muscle tissue containing plasmodia revealed intense labeling of spores both within the spore-producing plasmodia and in the flesh of infected Atlantic salmon. As few as 100 spores were detected by immunoblotting, indicating that these mAbs have potential for use in developing a field-based diagnostic test.

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Section: Discussionmentioning

confidence: 99%

Analysis of Kudoa thyrsites (Myxozoa: Myxosporea) spore antigens using monoclonal antibodies

Chase¹,

Dawson-Coates²,

Haddow³

et al. 2001

Dis. Aquat. Org.

Self Cite

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“…Wills (19) and Patashnik et al (20) reported that parasite-produced enzymes cause post-mortem muscle degeneration in fish. Moran et al reported that myoliquefaction (21), and St-Hilarie et al (22) and Moran et al (17) reported that jelly meat decreased the value of fish to the extent that they could not be sold. Matsukane et al (14) reported that K. septempunctatapositive muscles showed no myoliquefaction.…”

Section: Discussionmentioning

confidence: 99%

<i>Kudoa septempunctata</i>-Induced Gastroenteritis in Humans after Flounder Consumption in Japan: a Case-Controlled Study

et al. 2015

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SUMMARY: Raw fish consumption is increasing worldwide. Since around the year 2000, western regions of Japan have reported a foodborne disease of unknown cause that occurred after the consumption of flounder. In October 2010, a particularly large outbreak was reported in these regions among individuals who consumed flounder fish that had been raised in aquaculture systems. The median incubation period was 5 h (range, 4-19 h), and the most frequently reported symptom was diarrhea (80z). The risk estimate of the consumption of flounder was significantly higher than that of the development of symptoms (odds ratio ＝ 9.50; 95z confidence interval, 1.59-/). According to a trace-back investigation, all of the flounder responsible for the outbreak were raised in aquaculture systems. Microscopic examination revealed that the median amount of Kudoa septempunctata present in the muscle of flounder fish from the aquaculture farm was 4.5 × 10 3 spores/g (range, 1.0 × 10 3 -9.6 × 10 6 spores/ g). The number of K. septempunctata spores required for the development of illness, as estimated using the Monte Carlo simulation, was 7.2 × 10 7 spores/g; therefore, thus this might be the minimum ingestion threshold for the development of gastrointestinal symptoms. As a public health measure, the current study results should be referred to for the prevention of the gastrointestinal symptoms related to the consumption of flounder; the national public health authority has disseminated these results. We concluded that K. septempunctata-contaminated flounder fish were associated with the gastrointestinal symptoms of this recent outbreak.

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“…Several methods have been developed for the quantitation of Kuoda thyrsites infections in Atlantic salmon, including histology, spore counts and ELISA (St-Hilaire et al 1997a,b, Moran et al 1999b, DawsonCoates et al 2003, Taylor & Jones 2005. Histological examination of muscle for the presence of plasmodia has been the standard technique for determining K. thyrsites infection levels, and this measure has been shown to correlate well with post-mortem flesh quality (Dawson-Coates et al 2003).…”

Section: Discussionmentioning

confidence: 99%

“…However, following death, infected somatic muscle tissue is proteolytically digested, and the degree of 'myoliquefaction' has been correlated to the severity of K. thyrsites infections (St-Hilaire et al 1997a, Dawson-Coates et al 2003. Post-mortem tissue damage associated with K. thyrsites infections has resulted in an economic cost to Atlantic salmon producers in British Columbia (Canada) estimated at 50 million Canadian dollars in lost revenues in 2002 alone.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of an RNA- and DNA-based quantitative PCR assay for determination of Kudoa thyrsites infection levels in Atlantic salmon Salmo salar

Funk

Raap²,

Sojonky³

et al. 2007

Dis. Aquat. Org.

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Quantitative PCR (QPCR) methods targeting the 18S rDNA gene (DNA QPCR) and cathepsin L mRNA (RNA QPCR) from Kudoa thyrsites (Gilchrist) were developed and compared with histology for determination of K. thyrsites infection levels in Atlantic salmon Salmo salar L. Both QPCR tests were specific, reproducible and sensitive down to 3 copies. DNA QPCR was able to detect lower K. thyrsites infection levels than those detected by RNA QPCR and histology. The higher sensitivity of the DNA-based test compared with the RNA-based test appeared to be biological in nature and suggested that when infection levels were low, there were fewer copies of cathepsin L mRNA than 18S rDNA genes. However, all 3 diagnostic methods were highly correlated. Regression analyses comparing DNA QPCR and histology data from 2 distinct groups of fish showed that the relationship between these 2 diagnostic methods was reproducible. A logistic regression analysis comparing diagnostic data with a visual assessment of post-mortem flesh quality indicated that histology was the single best predictor of flesh quality, followed by DNA QPCR and then RNA QPCR. KEY WORDS: Kudoa thyrsites · Atlantic salmon · Diagnostics · QPCR · RNA test · DNA test · Histology · Myoliquefaction Resale or republication not permitted without written consent of the publisherDis Aquat Org 75: [239][240][241][242][243][244][245][246][247][248][249] 2007 stage, it is difficult to discern biological and environmental factors affecting parasite abundance in the environment and, ultimately, the risk to farmed salmon. Efforts have been made to understand factors affecting the susceptibility of Atlantic salmon to K. thyrsites infections (Funk et al. 2004), but in the absence of a challenge model this type of work is also difficult. At present, management of the infection relies on site selection, optimising smolt quality and monitoring stock for the presence of myxospores. Therefore, development of an efficacious vaccine is arguably the most promising method with which to minimize the impacts of K. thyrsites on fillet quality. To facilitate vaccine development, improved diagnostics are required for measuring K. thyrsites infection levels.Kudoa thyrsites infection levels are routinely determined through examination of stained histological sections, and this measure has been shown to be a relatively good predictor for post-mortem flesh quality (Dawson-Coates et al. 2003). However, histology lacks the sensitivity required to quantify low-level infections and requires a minimum seawater exposure period of 900 degree days before plasmodia can be detected reliably (Moran et al. 1999b). Therefore, histological methods as a measure of vaccine efficacy preclude evaluation of low infection levels and prevent rapid evaluation of newly developed vaccine candidates.Standard PCR is routinely used to detect the Kudoa thyrsites small subunit ribosomal DNA (18S rDNA) (Hervio et al. 1997) and has detected K. thyrsites in smolts after sea water exposures of only 350 degree days (V. Funk unpu...

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A comparative study of muscle texture and intensity of Kudoa thyrsites infection in farm-reared Atlantic salmon Salmo salar on the Pacific coast of Canada

Cited by 44 publications

References 4 publications

Analysis of Kudoa thyrsites (Myxozoa: Myxosporea) spore antigens using monoclonal antibodies

Analysis of Kudoa thyrsites (Myxozoa: Myxosporea) spore antigens using monoclonal antibodies

<i>Kudoa septempunctata</i>-Induced Gastroenteritis in Humans after Flounder Consumption in Japan: a Case-Controlled Study

Development and validation of an RNA- and DNA-based quantitative PCR assay for determination of Kudoa thyrsites infection levels in Atlantic salmon Salmo salar

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