engleski

Isolation and characterisation of EVEX in glass eels (Anguilla anguilla).

Introduction: The European eel (Anguilla anguilla) is a catadromous species, an inhabitant of the Croatian rivers belonging to the Adriatic watershed. The species is critically endangered according to IUCN list and is facing an extremely high risk of extinction in the wild. Besides overfishing, and trafficking, the diseases like swim bladder nematode Anguillicoloides crassus, pathogenic bacteria, and pathogenic viruses: eel virus European (EVE), the eel virus European X (EVEX) and the anguillid herpesvirusare threatening its presence in European rivers. Totally 252.000 of glass eels were confiscated during trafficking at the Zagreb airport and placed into the tanks of the city zoo with the intention to be used for re-population of the natural habitats in Croatia. Methodology: Species was determinedby analyzing the nucleotide sequence of cytochrome c oxidase subunit 1. Parasitological, bacteriological and virological examinations were carried out by microscopic analysis, seeding of material from organs on blood agar ; and inoculating the homogenized tissues onto BF2 and EPC cell lines. Nucleic acid extraction and purification from cell culture supernatants were performed using a commercial kit. The extracted nucleic acids were used as a template for PCR and real- time RT-PCR. Viral RNAs were tested for EVE, EVEX and AnHV. New primers were designed for amplification and sequencing of EVEX N, P, M and G genes. Phylogenetic analysis was performed with obtained sequences. Results: The cytopathic effect (CPE) in the cell monolayer was observed under the light microscope. RT-qPCR tested positive for the rhabdovirus eel virus European X (EVEX). Bioinformatic analysis of EVEX genes showed that the isolated strain is unique and phylogenetically closest to strains previously described in France. Conclusion: Confirmed case of EVEX poses a doubt of re- population of the glass eels into natural habitats in Croatia. However, there is no data on the health status of the European eel populations from these rivers. Future research should be undertaken to support the epidemiological status of European eel in open waters.

EVEX ; anguilla anguilla ; trafficking ; phylogeny

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