Morphological, molecular and pathological appraisal of Callitetrarhynchus gracilis plerocerci (Lacistorhynchidae) infecting Atlantic little tunny (Euthynnusalletteratus) in Southeastern Mediterranean

Abstract

The Atlantic little tunny, Euthynnus alletteratus, is widely distributed in temperate and tropical waters of the Atlantic Ocean, Black and Mediterranean Seas. In this study, wild-caught little tunny from Egypt, were found to be naturally infected with trypanorhyncha metacestodes, and the overall prevalence rate of infection was 38.7%. The blastocysts were either loosely attached to the mesentery of infected fish, or firmly attached and deeply embedded within the hepatic parenchyma. These encysted plerocerci are identified as Callitetrarhynchus gracilis (Trypanorhyncha, Lacistorhynchidae) based on its morphological and molecular characterization. The morphological characteristics of C. gracilis including scolex shape; the bothridia groove; the presence of frontal glands; the length of post-larval (appendix); metabasal armature; the existence of ‘Chainette’ and satellite hooks of different size were studied and described by Light and Scanning electron microscope. The phylogenetic analysis of lsrDNA gene of plerocerci confirmed the identification of the species to be deeply embedded in genus Callitetrarhynchus. The histopathological examination revealed severe pathological changes in the affected organs, including necrosis, inflammatory reactions, fibrosis and migratory tracts of the parasitic larvae together with marked visceral organs adhesions. To the best of our knowledge, this is the first report describing the detection of C. gracilis in little tunny collected from the Abu Qir landing site in Alexandria, Egypt.

First molecular detection of the parasites Molicola uncinatus and Hepatoxylon trichiuri (Cestoda: Trypanorhyncha) infecting the silver scabbardfish Lepidopus caudatus from the Central Mediterranean Sea: Implications for the seafood quality and safety

“…(Cammilleri et al, 2020;Levsen et al, 2018) and other parasites, such as Kudoa thyrsites (Gilchrist, 1924), responsible of post-mortem flesh liquefaction, with a detrimental effect on the fish product (Giulietti et al, 2019). Also, few records on the occurrence of the trypanorhynch tapeworms from the silver scabbardfish and/or other fish species of the Mediterranean Sea have been so far published (Abdelsalam et al, 2016;Muscolino, Giarratana, Giuffrida, & Panebianco, 2012;Tiralongo, Messina, Poidomani, Salvaggio, & Lombardo, 2020). These reports were only based on morphological analysis of merocercoids or plerocercoids detected in teleost fish species.…”

“…Their occurrence in the muscles alters the fish flesh quality, reducing the marketability of commercially important fish species (Dias, Sao Clemente, Pinto, & Knoff, 2011;da Fonseca, de Sao Clemente, Felizardo, Gomes, & Knoff, 2012;Deardorff, Raybourne, & Mattis, 1984;Giarratana et al, 2014;Samn, Metwally, Zeina, & Khalaf Allah, 2014;Abdelsalam et al, 2016;Santoro et al, 2018;Oliveira, Kuraiem, Fonseca, Gomes, & Knoff, 2019;Guardone et al, 2020). Heavily infected fish fillets result unappealing to consumers; thus, the presence of these parasites causes economic loss to the fishing industry (Abdelsalam et al, 2016;Deardorff et al, 1984;Giarratana et al, 2014;Samn et al, 2014;Santoro et al, 2018). Few cases of accidental human ingestion of Trypanorhyncha larvae were reported, showing no clear evidence of pathogenic effects in humans (Bates, 1990;Lima dos Santos & Howgate, 2011).…”

Callitetrarhynchus gracilis (Rudolphi, 1819) Pintner, 1931 (Cestoda: Trypanorhyncha) parasitizing the musculature of Sardinella brasiliensis (Steindachner, 1879) (Actinopterygii) off the coast of the state of Rio de Janeiro, Brazil

“…Several occurrences of C . gracilis in marine fish in Brazil and in the world have recently been reported [ 29 , 30 , 31 , 32 , 33 ]. The morphology of microtriches observed on the bothrial rim of the transition zone between proximal and distal surfaces are in accordance with observations of Palm [ 9 ] and Chervy [ 20 ].…”

Bioaccumulation of polycyclic aromatic hydrocarbons, histopathological alterations and parasito-fauna in bentho-pelagic host from Snake Island, Lagos, Nigeria

“…PAHs have been reported to cause structural damage to fish tissues (Correa & Gracia, 1990) increase the prevalence of parasitic protozoa infection (Hecker & Karbe, 2005) and decrease helminth infestation (Akinsanya et al, 2014(Akinsanya et al, , 2015. Histopathological and biochemical alterations in fish, microbial biomass such as hydrocarbon and non-hydrocarbon utilizers, and population dynamics of parasito-fauna could be used as bioindicators of polycyclic aromatic hydrocarbon contamination (Pothuluri & Cerniglia, 1994;Sures, 2004;Palm, 2011;Abdelsalam et al, 2015).…”