Livoneca redmanii Leach, 1818 (Cymothoidae) a parasitic isopod infesting the gills of the European seabass, Dicentrarchus labrax (Linnaeus, 1758): morphological and molecular characterization study

Abstract

Background Prevalence, morphology, and molecular characteristics of isopodiosis in the European seabass, Dicentrarchus labrax, in Egypt were assessed using light and electron microscopy and polymerase chain reaction targeting the mitochondrial COI (cytochrome oxidase c) gene. Results Adult parasites were found mainly in the branchial cavity between gill arches and to a lesser extent in the buccal cavity. They were morphologically identified as the Cymothoidae Livoneca redmanii Leach, 1818 (Crustacea: Isopoda). Obviously, a 23% prevalence rate of isopods was reported in D. labrax from Egyptian Mediterranean waters. Destructive and degenerative necrotic alterations with complete sloughing of gill lamellae of the infested fish were observed. DNA sequencing of the mitochondrial COI gene confirmed the identification of the parasite which was deposited in the GenBank under accession numbers MW600099, MZ208984, and MZ208985. Furthermore, the phylogenetic analysis demonstrated that parasites emerged from a monophyletic clade closely affiliated with L. redmanii and were clearly distinguished from other isopod genospecies. Conclusion The present investigation addresses L. redmanii infestation in D. labrax in Egypt and affirmed morphological properties via the scanning electron microscopy (SEM) and molecular characteristics of this isopod species. The drastic effects of this parasite on the infected fish were proven both clinically and histopathologically.

Recent Advances in Diagnosis of Pseudomonas Septicemia in Relation to Isopods Infestation in Pomadasys stridense

“…In order to efficiently detect parasites in marine fish species found in the Egyptian Mediterranean waters, the use of molecular methods such as DNA barcoding is essential. Particularly the mitochondrial COI gene of L. redmanii, which is analyzed to achieve accurate results (Abdallah & Hamouda, 2022). The purpose of this study was to investigate naturally occurring parasitic and bacterial co-infection in P. stridense fish in the Suez Canal region.…”