Cystidicola farionis		Contents		Rev 02/20/2024
Swimbladder Nematode		Classification		Hosts
		Morphology and Anatomy		Life Cycle
Return to Cystidicola Menu		Economic Importance		Damage
		Distribution		Management
Return to Cystidicolidae Menu		Feeding		References
		Go to Nemaplex HomePage		Go to Dictionary of Terminol;ogy

Classification:

Chromadorea

  Chromadoria

   Rhabditida

Spirurina

              Habronematoidea

               Cystidicolidae

           Cystidicola farionis Fischer, 1798

Synonyms:

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Morphology and Anatomy:

• Cuticle thin, without transverse striation.
• Mouth aperture spherical with two hook-like teeth
• Buccal cavity cylindrical with thick wall
• Esophagus long and narrow, 2.7mm long with slender center section encircled by nerve ring,

Female:

• . Body not coiled, 22-26 mm long.
• Vulva near mid body; vagina extends posteriorly which opens into two uteri.  One uterus extends backwards and then reflexes; the other extends forwards and then reflexes.
• Both ovaries are in short coils
• Females oviparous, eggs with thick shells and a tuft of filaments ate each pole.

Male:

• Coiled in posterior region, about 14mm long

• Nerrow caudal alae supported by genital papillae

• Monorchis, anteriorly directed testyis

• Two spicules, unequal size; long one is slender and about 750um long, shprt one about 160um long.

• Cloaca surrounded by narrow bursa. supported by papillae; 9 pairs precaudal, 5 single postcloacal in ech side of bursa 

Ref: Leiper, 1908

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Distribution:

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

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Feeding:

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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 fishpathogens.net)

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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.

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Ecosystem Functions and Services:

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Management:

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References:

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;  https://doi.org/10.3390/ijerph19116430

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: February 20, 2024.