Studies on lesions caused by plerocercoids of Triaenophorus nodulosmin some fish of an alpine lake, the Königssee |
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| Authors: | R W Hoffmann J Meder M Klein † K Osterkornj ‡ R D Negele § |
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| Institution: | Institut für Zoologie und Hydrobiologie, University of Munich, FRG;Bayer, Landesanstalt für Fischerei, Starnberg, FRG;Institut für Tierzucht und Tierhygiene, University of Munich, FRG;Bayer, Landesanstalt für Wasserforschung, Munich, FRG |
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| Abstract: | Lesions caused by plerocercoids of Triaenophorus nodulosus in the second intermediate hosts were studied in fish of an alpine lake, the Königssee. Four species (Arctic charr, Salvelinus alpinus; minnow, Phoxinus phoxinus; burbot, Lota lota: perch, Percafluviatilis) could be shown to be affected, whereas seven other fish species did not have macroscopical or histological signs of invasion. The capsules of T. nodulosus plerocercoids were usually located in liver tissue. Whereas only living parasites were found in charr and minnow, dead and destroyed plerocercoids could be demonstrated additionally in burbot and perch.
The histological picture is characterized by capsules surrounded by connective tissue and by fresh or older migration routes in charr and minnow. Furthermore, larvae migrating through the biliary ductules were found regularly in charr. In burbot and perch, different stages of destruction of the parasitic larvae took place. The ability to reject the parasite by immunological reactions seems to depend on the species of host. Even if heavy changes in the liver tissue could be demonstrated, no negative influences on condition and growth of affected fish could be established. |
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