학술논문
Production of Ceratonova shasta Myxospores from Salmon Carcasses: Carcass Removal Is Not a Viable Management Option.
Document Type
Academic Journal
Author
Foott JS; a U.S. Fish and Wildlife Service , California-Nevada Fish Health Center , 24411 Coleman Fish Hatchery Road, Anderson , California 96007 , USA.; Stone R; a U.S. Fish and Wildlife Service , California-Nevada Fish Health Center , 24411 Coleman Fish Hatchery Road, Anderson , California 96007 , USA.; Fogerty R; a U.S. Fish and Wildlife Service , California-Nevada Fish Health Center , 24411 Coleman Fish Hatchery Road, Anderson , California 96007 , USA.; True K; a U.S. Fish and Wildlife Service , California-Nevada Fish Health Center , 24411 Coleman Fish Hatchery Road, Anderson , California 96007 , USA.; Bolick A; a U.S. Fish and Wildlife Service , California-Nevada Fish Health Center , 24411 Coleman Fish Hatchery Road, Anderson , California 96007 , USA.; Bartholomew JL; b Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA.; Hallett SL; b Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA.; Buckles GR; b Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA.; Alexander JD; b Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA.
Source
Publisher: Wiley Country of Publication: United States NLM ID: 9884881 Publication Model: Print Cited Medium: Print ISSN: 0899-7659 (Print) Linking ISSN: 08997659 NLM ISO Abbreviation: J Aquat Anim Health Subsets: MEDLINE
Subject
Language
English
ISSN
0899-7659
Abstract
Severe infection by the endemic myxozoan parasite, Ceratonova (synonym, Ceratomyxa) shasta, has been associated with declines in and impaired recovery efforts of populations of fall-run Chinook Salmon Oncorhynchus tshawytscha in the Klamath River, California. The parasite has a complex life cycle involving a polychaete worm host as well as a salmon host. Myxospore transmission of this parasite, from salmon to polychaete, is a life cycle step during which there is a potential for applied disease management. A 3-year data set on prevalence, intensity, and spore characteristics of C. shasta myxospores was obtained from adult Chinook Salmon carcasses surveyed in the main stem of the Klamath River and three of its tributaries, Bogus Creek and the Shasta and Trinity rivers. Annual prevalence of myxospore detection in salmon intestines ranged from 22% to 52%, and spore concentration values per intestinal scraping ranged from 3.94 × 10(2) to 1.47 × 10(7) spores. A prevalence of 7.3% of all carcasses examined produced >5.0 × 10(5) spores, and these carcasses with "high" spore counts accounted for 76-95% of the total spores in a given spawning season. Molecular analysis of visually negative carcasses showed that 45-87% of these samples had parasite DNA, indicating they contained either low spore numbers or presporogonic stages of the parasite. Myxospores were rarely found in carcasses of freshly spawned adults but were common in decomposed carcasses of both sexes. The date of collection or age (based indirectly on FL) did not influence detection. The longer prespawn residence time for spring-run Chinook Salmon compared with that for fall-run Chinook Salmon in the Trinity River was associated with higher spore loads. The dye exclusion method for assessing spore viability in fresh smears indicated an inverse relationship in spore integrity and initial spore concentration. A carcass-removal pilot project in Bogus Creek for 6 weeks in the fall of 2008 (907 carcasses removed) and 2009 (1,799 carcasses removed) failed to measurably influence the DNA quantity of C. shasta in targeted waters. Combined with the high numbers of carcasses that contributed myxospores, we therefore deemed that this labor-intensive approach is not a viable management option to reduce the infectivity of C. shasta in Chinook Salmon in the Klamath River. Received January 23, 2015; accepted September 28, 2015.