Abstract
Parasitic isopod Ceratothoa oestroides (Cymothoidea, Isopoda) is a common and generalist buccal cavity-dweller in marine fish, recognised for its detrimental effect in fingerling and juvenile farmed European sea bass (Dicentrarchus labrax). Although distributed throughout the Mediterranean, the isopod provokes acute outbreaks mainly limited to particular endemic areas in Croatia (Adriatic Sea) and Greece (Aegean Sea). While numerous studies have previously evidenced its gross effect on farmed fish (i.e. decreased condition index, slower growth rate, lethargy and mortality), details on the host-parasite interaction are still lacking. Therefore, using a multimethodological approach, we closely examined the structure and appearance of isopod body parts acting in the attachment and feeding (stereomicroscopy, scanning and transmission electron microscopy), and the extent of host tissues damage (histology, immunohistochemistry, micro-computational tomography) induced by parasitation. Interestingly, while hematophagous nature of the parasite has been previously postulated we found no unambiguous data to support this; we observed host tissues fragmentation and extensive hyperplasia at the parasitation site, and no structures indicative of heme detoxifying mechanisms in the parasite gut, or other traces of a blood meal. The bacterial biofilm covering C. oestroides mouthparts and pereopods suggests that the isopod may play a role in conveying secondary pathogens to the infected host, or alternatively, it serves the parasite in normal interaction with its environment.
Highlights
Cymothoidae encompasses obligate, mostly marine isopod parasites, and forms the superfamily Cymothooidea Wägele, 1989 with families Corallanidae, Aegidae and Tridentellidae [1].Cymothoidae are typically parasitic in teleost fish, they infect Chondrichthyes, jellyfish, cephalopods, crustaceans and amphibians
We described a range of unknown traits of adult C. oestroides parasitation in the buccal cavity of European sea bass fingerlings using a multimethodological approach: i) histology and immunohistochemistry to assess tissues damage and infer the feeding strategy of the isopod; ii) 2 and 3D visualisation using micro-computational tomography (μ-CT) to gain robust data on parasite attachment strategy; iii) stereomicroscopy to describe ontogeny of mouthparts in
Paired male and female were settled at the floor of oro-pharyngeal cavity of infected European sea bass; female mostly logged centrally in the buccal cavity, and the male in the pharynx, the latter attached right or left laterally to gill rakers
Summary
Cymothoidae encompasses obligate, mostly marine isopod parasites, and forms the superfamily Cymothooidea Wägele, 1989 with families Corallanidae, Aegidae and Tridentellidae [1].Cymothoidae are typically parasitic in teleost fish, they infect Chondrichthyes, jellyfish, cephalopods, crustaceans and amphibians. Its direct life cycle includes mating of the paired adults settled in fish buccal cavity, embryonic development to pullus I and II stage, release of infective and swimming stage or pullus II (manca), its attachment to the novel hosts and protandric maturation. The latter encompasses puberty period of male, transitory stage, puberty period of female and maturation of the female [5,6]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
