Ichthyobodo salmonis sp. n. (Ichthyobodonidae, Kinetoplastida), an euryhaline ectoparasite infecting Atlantic salmon ( Salmo salar L.)

• Published in: Parasitology
• Main Authors: ISAKSEN, TROND E., KARLSBAKK, EGIL, WATANABE, KUNINORI, NYLUND, ARE
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2011
• Subjects: Infectious Diseases; Animal Science and Zoology; Parasitology; Todal; Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1017/s0031182011000916; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0031182011000916

SUMMARY Phylogenetic analyses of SSU rDNA sequences have previously revealed the existence of 2 Ichthyobodo species able to infect Atlantic salmon ( Salmo salar L.). Ichthyobodo necator sensu stricto (s.s.) is assumed to be a freshwater parasite, while a genetically distinct but undescribed species, Ichthyobodo sp. II sensu Todal et al . (2004) have been detected on Atlantic salmon in both fresh- and seawater. In the present study a morphological description of Ichthyobodo sp. II from the gills of salmon reared in fresh-, brackish- and seawater is presented, using both light- and electron microscopy. Comparative morphometry show that Ichthyobodo sp. II from both freshwater and seawater displays a different cell shape, and is significantly smaller than I. necator s.s. Also, ultrastructural characteristics distinguish these two species, notably differences in the attachment region and the presence of spine-like surface projections in Ichthyobodo sp. II. Based on both unique SSU rDNA sequences and morphological characteristics, we conclude that Ichthyobodo sp. II. represents a novel species for which we propose the name Ichthyobodo salmonis sp. n.