title: Proliferative renal myxosporidiosis in spawning coho salmon (Oncorhynchus kisutch) in British Columbia and Washington.
abstract: An unidentified myxosporean parasite (CKX) is described from the kidney of approximately 80% of spawning coho salmon Oncorhynchus kisutch (Walbaum) in British Columbia, Canada and Washington, United States of America. Morphological features were described using light and electron microscopy. Sequencing of polymerase chain reaction (PCR) amplified 18S ribosomal RNA gene and in situ hybridisation were used to further characterise CKX. The parasite occurred with a focal distribution within tubule epithelial cells, the tubule lumen and the interstitium as primary cells containing from one to at least 16 secondary cells. Luminal stages were degenerate and sporogony was not observed. In situ hybridisation using a digoxygenin-labelled DNA probe confirmed CKX to be the source of DNA used in PCR analyses. CKX 18S rDNA sequences were most similar (97%) to those of Sphaerospora oncorhynchi. Phylogenetic analysis revealed similarities among the 18S rDNA sequences of CKX, S. oncorhynchi and Myxidium lieberkuehni. CKX is hypothesised to be the abortive extrasporogonic development of a Sphaerospora sp. or Myxidium sp. occurring in immune-incompetent spawning and senescent salmon.
authors.affiliation: Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9T 6N7, Canada. joness@pac.dfo-mpo.gc.ca
authors.forename: Simon
authors.initials: S
authors.lastname: Jones
authors.forename: Gina
authors.initials: G
authors.lastname: Prosperi-Porta
authors.forename: Sheila
authors.initials: S
authors.lastname: Dawe
authors.forename: Janice
authors.initials: J
authors.lastname: Blackbourn
authors.forename: Kimberley
authors.initials: K
authors.lastname: Taylor
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Lowe
authors.forename: Andrea
authors.initials: A
authors.lastname: Osborn
mesh_terms: D000818:Animals; D001483:Base Sequence; D001955:British Columbia / Q000453:epidemiology; D017931:DNA Primers; D056890:Eukaryota / Q000235:genetics* / Q000648:ultrastructure; D005393:Fish Diseases / Q000469:parasitology* / Q000473:pathology; D006652:Histological Techniques / Q000662:veterinary; D017403:In Situ Hybridization / Q000662:veterinary; D007674:Kidney Diseases / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D008854:Microscopy, Electron / Q000662:veterinary; D008969:Molecular Sequence Data; D017684:Oncorhynchus kisutch; D010802:Phylogeny; D011529:Protozoan Infections, Animal / Q000453:epidemiology* / Q000473:pathology; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000662:veterinary; D014861:Washington / Q000453:epidemiology
chemical_list: D017931:DNA Primers; D012337:RNA, Ribosomal, 18S