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

Diseases of Aquatic Organisms

By:
, , , , , , ,
DOI: 10.3354/dao02626

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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.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Parasitic infection by larval helminths in Antarctic fishes: pathological changes and impact on the host body condition index
Series title:
Diseases of Aquatic Organisms
DOI:
10.3354/dao02626
Volume
105
Issue:
2
Year Published:
2013
Language:
English
Publisher:
Inter-Research
Contributing office(s):
National Wildlife Health Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
139
Last page:
148