Current diagnostic methods
@Roba Olana
Clinical and Histological Methods
- The name ‘salamandrivorans’ refers to the extensive skin destruction and rapid mortality observed in infected salamanders. The affected skin can show alterations from normal – changes in colouration, roughening, accumulation of sloughed skin and excessive sloughing. (EFSA et al., 2017)
- Microscopic observation of the fungus in the skin of infected salamanders is possible, but requires experience and proficiency. Possible sample types are skin scrapings or sections of skin from live salamanders, fresh dead specimens as well as formalin preserved specimens. (EFSA et al., 2017)
- Clinical healthy, yet infected animals pose an important risk for introducing or spreading Bsal. At the moment, such individuals can only be identified with PCR assays. PCR assays are also the only method of differentiating between pathogens (Bd v Bsal) after clinical assessment.
Duplex qPCR
- The limit of detection (analytical sensitivity) of Bd/Bsal duplex real-time PCR is at the level of 0.1 genomic equivalent of a zoospore, thus allowing detection of the fungi in minute amounts (0.1 GE, retrievable in pre- or subclinical phases of the disease).
Performance Indicators
- Main issues outlines in the 2016 OIE aquatic manual were lack of diagnostic sensitivity (DSe) and diagnostic specificity (DSp) of the test. The (EFSA et al., 2017) team however, realized that there is enough data to estimate those variables and found results consistent with the OIE requirements.
- Sensitivity
- Specificity
Duplec qPCR vis-a-vis OIE Manual of Diagnostic Tests for Aquatic Animals
References
| (Author, year) | Link |
|---|---|
| (OIE, 2019) | https://www.oie.int/en/standard-setting/aquatic-manual/access-online/ |
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