Characterization of Cryptocaryon irritans, a parasite isolated from marine fishes in Taiwan

• Published in: Diseases of aquatic organisms Vol. 54; no. 2; pp. 147 - 156
• Main Authors: YAMBOT, Apolinario V, SONGL, Yen-Ling, SUNG, Hung-Hung
• Format: Journal Article
• Language: English
• Published: Oldendorf Inter-Research 31.03.2003
• Subjects: Animals; Animals, Wild; Aquaculture; Base Sequence; Biological and medical sciences; Brackish; Ciliophora - classification; Ciliophora - genetics; Ciliophora - isolation & purification; Ciliophora Infections - parasitology; Ciliophora Infections - pathology; Ciliophora Infections - veterinary; Cryptocaryon irritans; cryptocaryoniasis; DNA, Protozoan - chemistry; DNA, Protozoan - genetics; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; Fish Diseases - parasitology; Fish Diseases - pathology; Fishes; Fundamental and applied biological sciences. Psychology; Genetic Variation; Genetics of eukaryotes. Biological and molecular evolution; Gills - parasitology; Gills - pathology; Marine; Molecular Sequence Data; Phylogeny; Population genetics, reproduction patterns; Protozoa; rRNA 18S; rRNA 5.8S; Sequence Alignment; Sequence Analysis, DNA; Taiwan; Asia; Taiwan; ISEW, Taiwan; Geography; Brackish water environment; Host parasite relation; Protozoal disease; Lates calcarifer; Genetic variability; Ribosomal DNA; Phylogeny; 18S-RNA; Population genetics; Marine environment; Pisces; Intraspecific comparison; 5.8S-RNA; Protozoa; Cryptocaryon irritans; Nucleotide sequence; rDNA sequence; Parasite; Host; Zoopathogen; Parasitosis; Infection; Variants; Vertebrata; Characteristics; Isolate; Ciliata
• ISSN: 0177-5103; 1616-1580
• DOI: 10.3354/dao054147

The ciliated protozoan parasite Cryptocaryon irritans infecting marine fishes in Taiwan is described. Developmental characteristics and sequences of the ribosomal DNA regions such as part of 18 S, the entire first internal transcribed spacer, and part of 5.8 S of various Taiwan isolates of C. irritans were investigated. A total of 5 isolates was obtained from different fish-host species and localities, the majority from cultured fish species. C. irritans from Taiwan is able to shift its developmental characteristics, i.e. from non-adherent to adherent tomonts, from individualistic to aggregate-forming tomonts, from infection of the gills only to infection of the gills and body. Thus, it is not possible to classify strains of C. irritans on the basis of these parameters. Premature tomonts that developed from dead fishes were able to produce theronts that could infect fish host. Isolates from Pingtung and the USA had identical nucleotide sequences while an isolate from Malaysia was identical to an Israel isolate. Percentage variation among pairs of Taiwan isolates showed a higher degree of variation than isolate sequences listed in GenBank. Sequence analysis revealed highly aberrant isolates in Taiwan, and a phylogenetic tree distinguished a marine and a low-salinity variant. C. irritans from marine fishes in Taiwan, therefore, display some characteristics not previously reported. Since manipulation of salinity in brackishwater ponds and marine cage sites is not feasible, there is a need to develop new strategies for the control and prevention of cryptocaryoniasis.