title: A new myxozoan from feral goldfish (Carassius auratus).
abstract: In February 2004, a mass die-off of common goldfish Carassius auratus L., presumptively caused by bacterial coldwater disease (Flavobacterium psychrophilum), occurred at Fern Ridge Reservoir, Oregon. A range of size classes was affected, but all mature fish were female and all fish were infected with a single myxozoan, Chloromyxum auratum n. sp. No histological changes were observed associated with the parasite. Infection was represented by mictosporic plasmodia and free-floating spores in the gall bladder. Parasite spores were nearly spherical, 13.6 microm long x 12.6 microm wide x 13.1 microm thick, and possessed 4 equal-sized polar capsules. Spores had a coglike appearance in apical view because of distinct ridges 2.1 microm high protruding from the valve cells. There were 6-9 extrasutural ridges per valve (15-20 ridges per spore), aligned along the longitudinal axis, with some branching, and convergence at both poles. Morphologically, spores identified most closely with Chloromyxum cristatum Léger, 1906; however, 18S rDNA sequence data indicated only 97.5% similarity over 2,076 bp with Chloromyxum cyprini, the only synonym of C. cristatum for which DNA data are available; additional sequence data may reveal the other synonyms to be distinct species. This is the first record of a species of Chloromyxum from goldfish.
authors.affiliation: Center for Fish Disease Research, Department of Microbiology, Oregon State University, Nash Hall 220, Corvallis, Oregon 97331, USA.
authors.forename: Sascha L
authors.initials: SL
authors.lastname: Hallett
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Atkinson
authors.forename: Richard A
authors.initials: RA
authors.lastname: Holt
authors.forename: Craig R
authors.initials: CR
authors.lastname: Banner
authors.forename: Jerri L
authors.initials: JL
authors.lastname: Bartholomew
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001483:Base Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000302:isolation & purification; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D005393:Fish Diseases / Q000453:epidemiology / Q000469:parasitology*; D005618:Fresh Water; D005704:Gallbladder / Q000469:parasitology; D005705:Gallbladder Diseases / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D006054:Goldfish / Q000469:parasitology*; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D008969:Molecular Sequence Data; D009922:Oregon / Q000453:epidemiology; D011529:Protozoan Infections, Animal / Q000453:epidemiology / Q000469:parasitology*; D017422:Sequence Analysis, DNA / Q000662:veterinary; D033761:Spores, Protozoan / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure
chemical_list: D016054:DNA, Protozoan