DAO 105:139-148 (2013)  -  doi:10.3354/dao02626

Parasitic infection by larval helminths in Antarctic fishes: pathological changes and impact on the host body condition index

Mario Santoro1,2,*, Simonetta Mattiucci1, Thierry Work3, Roberta Cimmaruta2, Valentina Nardi1,2, Paolo Cipriani1, Bruno Bellisario2, Giuseppe Nascetti

1Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Piazzale Aldo Moro, 00185 Rome, Italy
2Department of Ecological and Biological Sciences, Tuscia University, Viale dell’Università sn 01100 Viterbo, Italy
3US Geological Survey, National Wildlife Health Center, Honolulu Field Station, PO Box 50167, Honolulu, Hawaii 96850, USA

ABSTRACT: We examined pathological changes and relationship between body condition index (BCI) and parasitic infection in 5 species of fish, including 42 icefish Chionodraco hamatus (Channichtyidae), 2 dragonfish Cygnodraco mawsoni (Bathydraconidae), 30 emerald rock cod Trematomus bernacchii, 46 striped rock cod T. hansoni and 9 dusty rock cod T. newnesi (Nototheniidae) from the Ross Sea, Antarctica. All parasites were identified by a combination of morphology and mtDNA cytochrome-oxidase-2 sequence (mtDNA cox2) analysis, except Contracaecum osculatum s.l., for which only the latter was used. Five larval taxa were associated with pathological changes including 2 sibling species (D and E) of the C. osculatum species complex and 3 cestodes including plerocercoids of a diphyllobothridean, and 2 tetraphyllidean forms including cercoids with monolocular and bilocular bothridia. The most heavily infected hosts were C. hamatus and C. mawsoni, with C. hamatus most often infected by C. osculatum sp. D and sp. E and diphyllobothrideans, while C. mawsoni was most often infected with tetraphyllidean forms. Histologically, all fish showed varying severity of chronic inflammation associated with larval forms of helminths. Diphyllobothrideans and C. osculatum spp. were located in gastric muscularis or liver and were associated with necrosis and mild to marked fibrosis. Moderate multifocal rectal mucosal chronic inflammation was associated with attached tetraphyllidean scolices. C. hamatus showed a strong negative correlation between BCI and parasite burden.


KEY WORDS: Diphyllobothridean · Tetraphyllidean · Contracaecum osculatum s.l. · Antarctic fish · Ross Sea · Pathology


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Cite this article as: Santoro M, Mattiucci S, Work T, Cimmaruta R and others (2013) Parasitic infection by larval helminths in Antarctic fishes: pathological changes and impact on the host body condition index. Dis Aquat Org 105:139-148

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