Ciliates Associated with Sea Cucumbers


Category 4 (Negligible Regulatory Significance in Canada)

Common, generally accepted names of the organism or disease agent

Ciliates of sea cucumbers

Scientific name or taxonomic affiliation

Unidentified species of ciliates have been observed in close association with sea cucumbers.

Geographic distribution

Probably ubiquitous but each species may have a limited geographic.

Host species

Parastichopis californicus, Cucumaria frondosa and probably other species of holothurians.

Impact on the host

Numerous ciliates were observed free in the lumen and closely associated with the epithelial lining of the respiratory tree of two P. californicus maintained for about 6 months in a display tank, Departure Bay, British Columbia, Canada. Many ciliates similar in morphology to Type A from the intestinal tract of sea urchins were detected in the intestinal tract of 1 in 60 C. frondosa from Passamquoddy Bay, New Brunswick, Canada. There was no apparent host response nor tissue damage associated with any of the ciliates.

Diagnostic techniques

Histology: Ciliates adjacent to the epithelial surface with no evidence of tissue damage.

Figure 1. Section through two ciliates in the lumen of the respiratory tree of Parastichopis californicus from a display tank in British Columbia, Canada. Haematoxylin and eosin stain.

Figure 2. Cross section in the region of the macronucleus of two ciliates (arrows) closely associated with the epithelium of the respiratory tree of the same Parastichopis californicus featured in Fig. 1. Haematoxylin and eosin stain.

Methods of control

Prevention and control impractical. These ciliates are ubiquitous.


MacCallum, G.S., J. Blackbourn, S.E. McGladdery, S.M. Bower and J.T. Davidson. 2001. Disease issues relevant to the culture of shellfish in Atlantic and Pacific Canada. Bulletin of the Aquaculture Association of Canada 101-3: 5-12.

Citation Information

Bower, S.M. (2004): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Ciliates Associated with Sea Cucumbers.

Date last revised: June 2004
Comments to Susan Bower

Date modified: