title: Ichthyobodo necator (Kinetoplastida)--a complex of sibling species.
abstract: Ichthyobodo necator is a parasitic flagellate that attacks fishes, causing disease problems in freshwater worldwide. Findings of similar flagellates in strictly marine fishes have indicated that ichthyobodiosis may be caused by more than 1 flagellate species. We obtained partial small subunit rDNA (ssu rDNA) sequences of 14 Ichthyobodo isolates originating from fishes in Norway, Japan, Singapore, South Africa and Brazil, and identified 8 strains or species, including 2 species infecting cultured salmon in Norway. An Ichthyobodo species isolated from the skin of Atlantic salmon parr in freshwater is suggested to represent L. necator sensu stricto, while another species, showing particular affinity for the gills, infects salmon in both fresh- and seawater. Atlantic cod is infected with a marine Ichthyobodo species unrelated to those infecting salmonids; 2 cyprinids originating from different parts of the world had related Ichthyobodo strains/species, and 2 isolates from unrelated North and South American fishes were also closely related. The phylogenetic relationships of the Ichthyobodo isolates is described, and the implications of the molecular findings on past and future morphological studies of Ichthyobodo spp. are discussed.
authors.affiliation: Department of Fisheries and Marine Biology, University of Bergen, 5020 Bergen, Norway.
authors.forename: Jan Arvid
authors.initials: JA
authors.lastname: Todal
authors.forename: Egil
authors.initials: E
authors.lastname: Karlsbakk
authors.forename: Trond E
authors.initials: TE
authors.lastname: Isaksen
authors.forename: Heidrun
authors.initials: H
authors.lastname: Plarre
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Urawa
authors.forename: Anna
authors.initials: A
authors.lastname: Mouton
authors.forename: Erik
authors.initials: E
authors.lastname: Hoel
authors.forename: Christian W R
authors.initials: CW
authors.lastname: Koren
authors.forename: Are
authors.initials: A
authors.lastname: Nylund
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004275:DNA, Ribosomal / Q000235:genetics; D005393:Fish Diseases / Q000469:parasitology*; D005399:Fishes; D005843:Geography; D016830:Kinetoplastida / Q000145:classification* / Q000235:genetics*; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D011528:Protozoan Infections / Q000235:genetics; D011529:Protozoan Infections, Animal; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D004275:DNA, Ribosomal