Cystidicola farionis




Rev 10/25/2022

Swimbladder Nematode Classification Hosts
Morphology and Anatomy Life Cycle
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           Cystidicola farionis Fischer, 1798



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Morphology and Anatomy:



Ref: Leiper, 1908



Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:


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Commonly found in the swimbladder of salmonid fish in Europe and North America.

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 Swimbladder parasites of fish.
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Biology and Ecology:


The trehalose level of Cystidicola farionis from the swimbladdedr of European smelt was almost four times higher in adult nematodes than in larvae. In contrast, the activity of both enzymes (trehalose 6-phosphate synthase, TPS and trehalose 6-phosphate phosphatase, TPP) involved in the synthesis of trehalose was higher in larvae than in adults under optimal conditions.

 The optimum pH for TPS isolated from larvae and adults was pH 7.0. The optimum pH for TPP from larvae and adults was pH 7.0 and pH 8.0, respectively. The optimal temperature was 20 °C, and Mg2+ ions were an activator for trehalose-synthetizing enzymes from both sources.

The dynamic transformation of trehalose in the nematode developing inside the swim bladder of the smelt appears to be an important metabolic pathway in the nematode survival strategy. (Dmitrijyuk et al., 2022).

Cystidicola sp in the fish swimbldder (photograph from


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Life Cycle:

Fish are the definitive host. Nematode eggs are ingested by amphipods and juveniles develop the infective third-stage juvenils in the intermediate hosts. Development to the third stage may take as long as 7 weeks in water temperatures below 15C. Third-stage larvae of C. fcrrionis grew considerably in the intermediate hosts and the gonads became well developed. Similar development has been reported in other cystidicolids (Smith and Lanketer, 1979). Infection of the definitive host occurs when amphipods are consumed by fish.

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters
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Ecosystem Functions and Services:


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Dmitrijyuk, M., Szczotko, M., Kubiak, K., Dziekonska-Rynko, J., Cichoka, J., Hliwa, P., Mierzejewska, K. 2022. Cystidicola farionis, a Swim Bladder Parasite of European Smelt: Characterization of the Nematode Trehalose Strategy. Int. Jour. Env. Public Health 19:6430;

Ko, R.C.; Anderson, R.C. 1969. A revision of the genus Cystidicola Fischer, 1798 (Nematoda: Spiruroidea) of the swim bladder of fishes.. Journal of the Fisheries Research Board of Canada. 26:849-864.

Leiper, R.T. 1908. Note on the anatomy of Cystidicola farionis. Prasitology 1:193-194

Smith, J.D., Lankester, M.W. 1979. Development of swim bladder nematodes (Cystidicola spp.) in their intermediate hosts. Can. J. Zool. 57:1736-1744.


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Copyright 1999 by Howard Ferris.
Revised: October 25, 2022.