OIE white spot syndrome virus PCR gives false-positive results in Cherax quadricarinatus

Claydon, Kerry; Cullen, Bradford; Owens, Leigh

doi:10.3354/dao062265

Cited by 46 publications

(34 citation statements)

References 12 publications

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“…The final product was compared with known sequences using Basic Local Alignment Search Tool (BLAST) (Altschul et al 1990) to determine phylogenetic homology. This is in line with the OIE confirmatory technique for WSSV (Claydon et al 2004).…”

Section: Sequencingsupporting

confidence: 66%

Susceptibility of juvenile European lobster Homarus gammarus to shrimp products infected with high and low doses of white spot syndrome virus

Bateman¹,

Munro²,

Uglow³

et al. 2012

Dis. Aquat. Org.

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White spot syndrome virus (WSSV) is the most important pathogen known to affect the sustainability and growth of the global penaeid shrimp farming industry. Although most commonly associated with penaeid shrimp farmed in warm waters, WSSV is also able to infect, cause disease in and kill a wide range of other decapod crustaceans, including lobsters, from temperate regions. In 2005, the European Union imported US$500 million worth of raw frozen or cooked frozen commodity products, much of which originated in regions positive for white spot disease (WSD). The presence of WSSV within the UK food market was verified by means of nested PCR performed on samples collected from a small-scale survey of supermarket commodity shrimp. Passage trials using inoculum derived from commodity shrimp from supermarkets and delivered by injection to specific pathogen-free Pacific white shrimp Litopenaeus vannamei led to rapid mortality and pathognomonic signs of WSD in the shrimp, demonstrating that WSSV present within commodity shrimp was viable. We exposed a representative European decapod crustacean, the European lobster Homarus gammarus, to a single feeding of WSSV-positive, supermarket-derived commodity shrimp, and to positive control material (L. vannamei infected with a high dose of WSSV). These trials demonstrated that lobsters fed positive control (high dose) frozen raw products succumbed to WSD and displayed pathognomonic signs associated with the disease as determined by means of histology and transmission electron microscopy. Lobsters fed WSSV-positive, supermarket-derived commodity shrimp (low dose) did not succumb to WSD (no mortality or pathognomonic signs of WSD) but demonstrated a low level or latent infection via PCR. This study confirms susceptibility of H. gammarus to WSSV via single feedings of previously frozen raw shrimp products obtained directly from supermarkets.

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Section: Sequencingsupporting

confidence: 66%

Susceptibility of juvenile European lobster Homarus gammarus to shrimp products infected with high and low doses of white spot syndrome virus

Bateman¹,

Munro²,

Uglow³

et al. 2012

Dis. Aquat. Org.

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“…Thus actual causes for mortalities may go underreported and transmission of new and novel disease agents may not be recognised (Alderman and Polglase, 1988;Edgerton et al, 2002aEdgerton, 2002;Edgerton and Owens, 1999;Romero and Jiménez, 2002). Additionally, reliance on molecular methods may lead to underreporting of disease causes and provide erroneous results Claydon et al, 2004). Future studies on crayfish should consider an integrated approach to sampling that ensures that samples are taken from individual animals for electron microscopy, histopathology, classical taxonomy, molecular biology and so on.…”

Section: Discussionmentioning

confidence: 95%

“…The official OIE method recommends a nested polymerase chain reaction (PCR) approach using primer sets developed by Lo et al (1997). However, Claydon et al (2004) expressed concerns with false WSSV positive results associated with the primer sets of Lo et al (1997) when used with C. quadricarinatus.…”

Section: Nimaviridaementioning

confidence: 98%

Diseases of crayfish: A review

Longshaw

2011

Journal of Invertebrate Pathology

138

112

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“…Positive PCR assays may indicate the presence of an infectious agent, but the technique does not verify the existence of an infection. In addition, falsepositives can be caused by poor specificity of PCR primers and resulting cross-reaction with DNA of nontarget organisms (Claydon et al 2004). …”

mentioning

confidence: 99%

Misuse of PCR assay for diagnosis of mollusc protistan infections

Burreson¹

2008

Dis. Aquat. Org.

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Polymerase chain reaction (PCR) assays are useful tools for pathogen surveillance, but they are only proxy indications of pathogen presence in that they detect a DNA sequence. To be useful for detection of actual infections, PCR assays must be thoroughly tested for sensitivity and specificity, and ultimately validated against a technique, typically histology, which allows visualization of the parasite in host tissues. There is growing use of PCR assays for pathogen surveillance, but too often the assumption is made that a positive PCR result verifies an infection in a tested host. This assumption is valid only if the assay has been properly validated for the geographic area and for the hosts examined. Researchers should interpret unvalidated PCR assay results with caution, and editors and reviewers should insist that robust validations support all assertions that PCR results confirm infections.KEY WORDS: PCR assay · Validation · Histology · In situ hybridization · Marteilia · Haplosporidium Resale or republication not permitted without written consent of the publisher Dis Aquat Org 80: [81][82][83] 2008 agent in a host' to 'the presence of a multiplying or otherwise developing or latent disease agent in a host' (OIE 2007, p. 9). PCR assays alone cannot determine that a parasite has become established in a host. To be interpreted appropriately, PCR-based analyses for determination of protistan pathogen infections must be validated against an established technique, typically histology, which allows visualization of the infective agent.As defined by Hiney (2001), validation is an investigation of the extent to which a technique can be legitimately used for a particular purpose. Validation determines whether the technique detects the species, whether it detects all strains and life history stages of that species (inclusivity), and whether there is a crossreaction with any non-target species (exclusivity) (Reece & Burreson 2004). The latter is particularly problematic because it is impossible to test any assay against all other organisms, so false positives from unknown cross-reactions are always a possibility. This becomes especially important if an assay is used in a new host, or new geographic area for which it has not been validated. Sequencing of amplification products can verify that the DNA is from the target organism, but it does not confirm that there is an actual infection.Validation against histology determines the extent to which the PCR assay detects an actual infection. Validation should be accomplished by field trials in which the same sample is tested by both PCR-based methods and histology. When using PCR assays to detect parasites in hosts or geographic regions where validation of the assay has not been accomplished, infections must be verified by histology. Of course, it is well documented through many validation studies that molecular diagnostic techniques are more sensitive than histology when infections are of low intensity, especially if the parasite is small. In these circumstance...

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OIE white spot syndrome virus PCR gives false-positive results in Cherax quadricarinatus

Cited by 46 publications

References 12 publications

Susceptibility of juvenile European lobster Homarus gammarus to shrimp products infected with high and low doses of white spot syndrome virus

Susceptibility of juvenile European lobster Homarus gammarus to shrimp products infected with high and low doses of white spot syndrome virus

Diseases of crayfish: A review

Misuse of PCR assay for diagnosis of mollusc protistan infections

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