title: Variability in triactinomyxon production from Tubifex tubifex populations from the same mitochondrial DNA lineage infected with Myxobolus cerebralis, the causative agent of whirling disease in salmonids.
abstract: Myxobolus cerebralis, the causative agent of whirling disease, infects both salmonid fish and an aquatic oligochaete, Tubifex tubifex. Although M. cerebralis has been detected in river drainages throughout the United States, disease severity among wild fish populations has been highly variable. Tubifex tubifex populations have been genetically characterized using sequences from the 16S mitochondrial DNA (mtDNA) gene, the 18S ribosomal RNA gene, the internal transcribed spacer region 1 (ITS1), and randomly amplified polymorphic DNA (RAPD). Our earlier work indicated that large differences in compatibility between the parasite and populations of T. tubifex may play a substantial role in the distribution of whirling disease and resulting mortality in different watersheds. In the present study, we examined 4 laboratory populations of T. tubifex belonging to 16S mtDNA lineage III and 1 population belonging to 16S mtDNA lineage I for triactinomyxon (TAM) production after infection with M. cerebralis myxospores. All 4 16S mtDNA lineage III populations produced TAMs, but statistically significant differences in TAM production were observed. Most individuals in the 16S mtDNA lineage III-infected populations produced TAMs. The 16S mtDNA lineage I population produced few TAMs. Further genetic characterization of the 16S mtDNA lineage III populations with RAPD markers indicated that populations producing similar levels of TAMs had more genetic similarity.
authors.affiliation: US Geological Survey, Western Fisheries Research Center, Seattle, Washington 98115, USA. charlotte_rasmussen@usgs.gov
authors.forename: Charlotte
authors.initials: C
authors.lastname: Rasmussen
authors.forename: Julie
authors.initials: J
authors.lastname: Zickovich
authors.forename: James R
authors.initials: JR
authors.lastname: Winton
authors.forename: Billie L
authors.initials: BL
authors.lastname: Kerans
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003063:Cnidaria / Q000502:physiology*; D021901:DNA, Intergenic / Q000737:chemistry; D004272:DNA, Mitochondrial / Q000032:analysis*; D005393:Fish Diseases / Q000469:parasitology; D009835:Oligochaeta / Q000235:genetics* / Q000469:parasitology*; D010273:Parasitic Diseases, Animal / Q000469:parasitology; D019105:Random Amplified Polymorphic DNA Technique; D012487:Salmonidae / Q000469:parasitology; D013170:Spores / Q000502:physiology
chemical_list: D021901:DNA, Intergenic; D004272:DNA, Mitochondrial