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Lack of Protection following Re‐Exposure of Chinook Salmon to Ceratonova shasta (Myxozoa)
Author(s) -
Hurst C. N.,
Bartholomew J. L.
Publication year - 2015
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1080/08997659.2014.970716
Subject(s) - chinook wind , biology , myxozoa , virulence , parasite hosting , genotype , oncorhynchus , zoology , fish <actinopterygii> , fishery , gene , genetics , world wide web , computer science
The recent identification of multiple genotypes of the salmonid parasite Ceratonova shasta with different virulence levels in Chinook Salmon Oncorhynchus tshawytscha suggests that it is possible to immunize fish against subsequent infection and disease. We hypothesized that exposure of Chinook Salmon to the less‐virulent parasite genotype (II) prior to the more virulent parasite genotype (I) would decrease disease and/or result in fewer mature parasites compared with fish only infected with the more virulent genotype. To test this hypothesis, fish were challenged in a combination of field and laboratory exposures, and we measured infection prevalence, percent morbidity, and mature parasite production. Neither mortality nor mature parasite production were reduced when fish were exposed to genotype II prior to genotype I compared with fish exposed only to genotype I, suggesting that protection against C. shasta using a less‐virulent genotype of the parasite does not occur. Received June 9, 2014; accepted September 19, 2014