Saving European Salmon from Gyrodactylus parasites
Gyrodactylus salaris is a parasite that severely harms many species of salmonid fish. It feeds on host skin and mucus, and has been the cause of the near complete depletion of young salmon in the affected rivers of Norway. Where the rivers are seriously affected by this pathogen, the salmon population has been eradicated. Furthermore, Gyrodactylus salaris was the reason for a 25% decrease in Norwegian wild salmon catch, while it can also be extremely dangerous to other types of European salmon. Salmon fishing carries economical significance in countries such as the United Kingdom, Finland, and Russia, which makes it increasingly important to identify Gyrodactylus infection throughout Europe. Therefore, a practical scientific framework for the detection of Gyrodactylus in Europe is imperative for both ecological and economical reasons. It is within this context that the consortium developed a method for Gyrodactylus diagnosis based on molecular DNA examinations, which are more reliable and precise than conventional diagnostic techniques. In fact, the DNA sequences of the diverse Gyrodactylus species exhibit differences and similarities that can be pinpointed and built upon so as to construct more precise diagnostic tests. Genetic-based testing is much more specific than microscopic testing. These research specialists identified and depicted sequences from variable region V4 of the small subunit ribosomal RNA (rRNA) gene, the rRNA internal transcribed spacer (ITS) and the intergenic spacer (IGS). Then, the differences between Gyrodactylus species (including the G. salaris species and those similar to it) can be identified by restriction enzyme digestion of amplified ITS. The researchers also revealed the diverse characteristics of G. salaris, G. thymalli, and other species via an examination of the IGS. Also, the differences within the ITS and IGS were scrutinised and it was concluded that these variations do not have a significant effect on the use of these areas of the genome so as to detect the species and strain under examination. As Gyrodactylus is a pathogen that constitutes a severe threat to salmon survival throughout Europe, it is essential that diagnostic testing methods be improved. This consortium's genetic research on the parasite provides a sound foundation for the establishment of specific diagnostic frameworks and techniques.
