first record of viral erythrocytic necrosis and ceratomyxa shasta noble, 1950 (myxozoa: myxosporea) in feral pink salmon (oncorhynchus gorbuscha walbaum). 19853999250
review of myxosporea of importance in salmonid fisheries and aquaculture in british columbia.several myxosporean parasites are of importance in fisheries and aquaculture in british columbia. the pkx organism and ceratomyxa shasta noble, 1950 cause disease and mortality, kudoa thyrsites (gilchrist, 1924) and henneguya salminicola ward, 1919 are of importance because they infect somatic muscle, cause unsightly cysts and soft flesh, and thus reduce the market value of the fish. myxobolus arcticus pugachev et khokhlov, 1979, an apparently non-pathogenic species, along with h. salminicola, i ...19948050752
the life cycle of ceratomyxa shasta, a myxosporean parasite of salmonids, requires a freshwater polychaete as an alternate host.the actinosporean life stage of ceratomyxa shasta, a myxozoan parasite of salmonids, and the annelid worm that serves as its alternate host were identified in laboratory transmission experiments and their roles were confirmed using molecular techniques. infection by the parasite occurred in susceptible fish that were either exposed to or force fed the freshwater polychaete, manayunkia speciosa, infected with the actinosporean. these observations were confirmed using the polymerase chain reaction ...19979379291
molecular characterization of the myxosporean associated with parasitic encephalitis of farmed atlantic salmon salmo salar in ireland.during seasonal epizootics of neurologic disease and mass mortality in the summers of 1992, 1993 and 1994 on a sea-farm in ireland, atlantic salmon salmo salar smolts suffered from encephalitis associated with infection by a neurotropic parasite. based on ultrastructural studies, this neurotropic parasite was identified as an intercellular presporogonic multicellular developmental stage of a histozoic myxosporean, possibly a myxobolus species. in order to generate sequence data for phylogenetic ...199910228877
development of a polymerase chain reaction diagnostic assay for ceratomyxa shasta, a myxosporean parasite of salmonid fish.a diagnostic procedure based on the polymerase chain reaction (pcr) was developed for the myxosporean parasite ceratomyxa shasta. three sets of oligonucleotide primers were designed to specifically amplify c. shasta ribosomal rna genes and several parameters of the assay were tested and optimised. a simple protocol for the processing of fish tissue samples was also developed. in a single round, 20 microliters volume reaction the optimised procedure allows the detection of 50 fg of purified c. sh ...199910349552
recent advances in our knowledge of the the last few years two factors have helped to significantly advance our understanding of the myxozoa. first, the phenomenal increase in fin fish aquaculture in the 1990s has lead to the increased importance of these parasites; in turn this has lead to intensified research efforts, which have increased knowledge of the development, diagnosis. and pathogenesis of myxozoans. the hallmark discovery in the 1980s that the life cycle of myxobolus cerebralis requires development of an actinosporean s ...200111456316
the occurrence and mechanisms of innate immunity against parasites in fish.parasitic infections in teleost fish are limited by constitutive innate defence mechanisms that render the host refractory or reduce the severity of infection. controlled challenge trials using naive animals provide indirect evidence of innate immunity as well as identifying the host range or specificity of a parasite, often when specific details of defence mechanism(s) are lacking. examples of parasites for which innate immunity may be inferred from cross-infectivity studies include gyrodactylu ...200111602199
mapping multiple genetic loci associated with ceratomyxa shasta resistance in oncorhynchus mykiss.ceratomyxa shasta is enzootic to some rivers of the pacific northwest and california, and has caused extensive mortalities of salmonids, the only known host of the actinosporean stage of the pathogen. mortalities from c. shasta are induced by severe inflammation and necrosis of the intestinal tract, and no therapeutants have been discovered for the treatment of ceratomyxosis. inheritance studies by previous investigators suggested that c. shasta resistance is genetically controlled, but none hav ...200314598990
monitoring ceratomyxa shasta infection during a hatchery rearing cycle: comparison of molecular, serological and histological methods.the prevalence of ceratomyxa shasta infection in production stocks of steelhead oncorhynchus mykiss and cutthroat trout o. clarki was monitored using a parasite-specific polymerase chain reaction (pcr) assay. for all 4 stocks of fish followed through their 1 yr rearing cycle, c. shasta infection was detected despite their genetic resistance to the disease and the treatment of the incoming water with ozone. infection was confirmed using serological methods and standard histological procedures, ex ...200415648834
application of a real-time pcr assay to detect and quantify the myxozoan parasite ceratomyxa shasta in river water samples.ceratomyxa shasta is a virulent pathogen of salmonid fishes that is enzootic in the pacific northwest of north america. current parasite detection methods involve sentinel fish exposures that are laborious and time-consuming. as a substitute, a filtering protocol and a quantitative real-time taqman polymerase chain reaction (qpcr) assay were developed to detect and enumerate parasite spores in river water. fluorescence was detected from both the myxospore and actinospore stages of the parasite b ...200616956058
involvement of manayunkia speciosa (annelida: polychaeta: sabellidae) in the life cycle of parvicapsula minibicornis, a myxozoan parasite of pacific salmon.a coelomic myxozoan infection was detected in freshwater polychaetes, manayunkia speciosa from the klamath river, oregon/california, a site enzootic for the myxozoan parasites ceratomyxa shasta and parvicapsula minibicornis. the tetractinomyxon type actinospores had a near-spherical spore body 7.9 x 7.1 microm, with 3 spherical, protruding polar capsules, no valve cell processes, and a binucleate sporoplasm. parvicapsula minibicornis-specific primers parvi1f and parvi2r amplified dna from infect ...200616995391
distribution and habitat characteristics of manayunkia speciosa and infection prevalence with the parasite ceratomyxa shasta in the klamath river, oregon-california.a survey for manayunkia speciosa, the freshwater polychaete host for the myxozoan parasite ceratomyxa shasta, was conducted from 2003 to 2005 as part of an integrated study of the epizootiology of ceratomyxosis in klamath river salmonids. substrata samples (n = 257) were collected in a variety of habitats from klamath lake to the mouth of the klamath river to document occurrence and relative abundance of the polychaete by habitat type and to estimate the prevalence of c. shasta within selected p ...200717436945
longevity of ceratomyxa shasta and parvicapsula minibicornis actinospore infectivity in the klamath river.infectious ceratomyxa shasta and parvicapsula minibicornis actinospores were present in klamath river samples collected in april, may, and june 2005. juvenile chinook salmon oncorhynchus tshawytscha exposed to river water maintained at the ambient klamath river temperature for 0, 4, 24, 72, and 168 h (7 d) developed asymptomatic infections from both parasites. elevated water temperature (18 degrees c) in june may have reduced actinospore viability, as both c. shasta and p. minibicornis infection ...200718201047
surveillance for ceratomyxa shasta in the puget sound watershed, washington.discovery of fish exhibiting clinical signs of ceratomyxosis in washington state prompted concern over the potential impact of the myxozoan parasite ceratomyxa shasta on native stocks of steelhead oncorhynchus mykiss (anadromous rainbow trout). to investigate these concerns, a survey of 16 freshwater systems within the puget sound watershed, including lake washington, was conducted by sentinel exposure of susceptible fish (cutthroat trout o. clarkii and rainbow trout). fish were exposed for 7 d ...200718201052
distribution and abundance of the salmonid parasite parvicapsula minibicornis (myxozoa) in the klamath river basin (oregon-california, u.s.a.).the distribution and abundance of the myxosporean parasite parvicapsula minibicornis in the klamath river mirrored that of ceratomyxa shasta, with which it shares both its vertebrate and invertebrate host. assay of fish held at sentinel sites and water samples collected from those sites showed that parasite prevalence was highest below iron gate dam, which is the barrier to anadromous salmon passage. above this barrier parasite levels fluctuated, with the parasite detected in the free-flowing ri ...200718286810
the effects of water velocity on the ceratomyxa shasta infectious cycle.ceratomyxa shasta is a myxozoan parasite identified as a contributor to salmon mortality in the klamath river, usa. the parasite has a complex life cycle involving a freshwater polychaete, manayunkia speciosa and a salmonid. as part of ongoing research on how environmental parameters influence parasite establishment and replication, we designed a laboratory experiment to examine the effect of water flow (velocity) on completion of the c. shasta infectious cycle. the experiment tested the effect ...200918803584
ceratomyxa (myxozoa: bivalvulida): robust taxon or genus of convenience?the genus ceratomyxa (myxozoa: myxosporea: bivalvulida) contains parasites that typically infect the gall bladders of marine teleosts. species of this genus have also been recorded from elasmobranchs, while the best known species (ceratomyxa shasta) is a systemic pathogen of fresh water salmonid fishes. here we characterise 10 new species of ceratomyxa from marine teleosts using morphometric and rdna sequence data. a phylogeny of all ceratomyxa species for which ssrdna sequence is available was ...200919460381
chronological development of ceratomyxa shasta in the polychaete host, manayunkia speciosa.the life cycle from release of myxospore sporoplasm to mature actinospore for the myxozoan parasite ceratomyxa shasta in the freshwater polychaete host is described. infection was initiated through exposure to lab-infected waters. mature myxospores were present in the gut of segment 4 by 2 hr post-exposure (pe). migration of early developmental stages occurred from the gut epithelium, through the nervous system, and into the epidermis. once the parasite reached the epidermis, development typical ...200919650688
disparate infection patterns of ceratomyxa shasta (myxozoa) in rainbow trout (oncorhynchus mykiss) and chinook salmon (oncorhynchus tshawytscha) correlate with internal transcribed spacer-1 sequence variation in the parasite.ceratomyxa shasta is a virulent myxosporean parasite of salmon and trout in the pacific northwest of north america. the parasite is endemic in the klamath river, oregon/california, where a series of dams prevent movement of fish hosts between the upper and lower parts of the basin. ceratomyxa shasta exhibits a range of infection patterns in different fish species above and below the dams. we hypothesised that the variations in infection and disease are indicators that different strains of the pa ...201019895812
effects of ceratomyxa shasta dose on a susceptible strain of rainbow trout and comparatively resistant chinook and coho salmon.ceratomyxa shasta infects salmon and trout, causing ceratomyxosis, a disease characterized by parasite proliferation in the intestine and death. we used laboratory challenges to investigate the infective dose for 3 fish species: a susceptible strain of rainbow trout oncorhynchus mykiss and comparatively resistant chinook o. tshawytscha and coho salmon o. kisutch. for susceptible rainbow trout, we determined the outcome of infection under conditions of varying parasite dose, fish size, and parasi ...200919899347
invasion of ceratomyxa shasta (myxozoa) and comparison of migration to the intestine between susceptible and resistant fish hosts.the myxozoan parasite ceratomyxa shasta infects salmonids causing ceratomyxosis, a disease elicited by proliferation of the parasite in the intestine. this parasite is endemic to the pacific northwest of north america and salmon and trout strains from endemic river basins show increased resistance to the parasite. it has been suggested that these resistant fish (i) exclude the parasite at the site of invasion and/or (ii) prevent establishment in the intestine. using parasites pre-labeled with a ...201020385137
spatial, temporal and host factors structure the ceratomyxa shasta (myxozoa) population in the klamath river basin.the myxozoan parasite ceratomyxa shasta is a virulent pathogen of salmonid fish in the klamath river, oregon/california, usa. we previously defined four principal genotypes of the parasite (o, i, ii, iii) based on a trinucleotide repeat (atc)(0-3) in internal transcribed spacer region 1 sequences. genotypes occur in sympatry and show marked host preference: i in chinook salmon (oncorhynchus tschawytscha) and ii in non-native rainbow trout (o. mykiss). in the present study, we sequenced the paras ...201020601174
mortality threshold for juvenile chinook salmon oncorhynchus tshawytscha in an epidemiological model of ceratomyxa shasta.the myxozoan parasite ceratomyxa shasta is a significant pathogen of juvenile chinook salmon oncorhynchus tshawytscha in the klamath river, california, usa. this parasite requires 2 hosts to complete its life cycle: a freshwater polychaete (manayunkia speciosa) and a salmonid. the complex life cycle and large geographic area where infection occurs make it difficult to monitor and manage ceratomyxosis. we present a model for ceratomyxosis-induced mortality in o. tshawytscha, from which parameters ...201021290897
relationship between temperature and c. shasta-induced mortality in klamath river salmonids.abstract water temperature influences almost every biological and physiological process of salmon, including disease resistance. in the klamath river (california), current thermal conditions are considered sub-optimal for juvenile salmon. in addition to borderline temperatures, these fish must contend with the myxozoan parasite ceratomyxa shasta, a significant cause of juvenile salmonid mortality in this system. this paper presents 2 studies, conducted from 2007-2010, that examine thermal e ...201122129468
Morphological and genetic analysis of three new species of Ceratomyxa Thélohan, 1892 (Myxozoa: Myxosporea) from carcharhinid sharks off Australia.Three new species of Ceratomyxa Thélohan, 1892 are described from the gall-bladders of two species of carcharhinid sharks collected off Heron and Lizard Islands on the Great Barrier Reef, Australia. Ceratomyxa carcharhini n. sp. and C. melanopteri n. sp. are described from Carcharhinus melanopterus (Quoy & Gaimard), and Ceratomyxa negaprioni n. sp. is described from Negaprion acutidens (Rüppell). These species are the first ceratomyxids reported from Australian elasmobranchs, and this is the fir ...201121898200
relationship between temperature and c. shasta-induced mortality in klamath river salmonids.abstract water temperature influences almost every biological and physiological process of salmon, including disease resistance. in the klamath river (california), current thermal conditions are considered sub-optimal for juvenile salmon. in addition to borderline temperatures, these fish must contend with the myxozoan parasite ceratomyxa shasta, a significant cause of juvenile salmonid mortality in this system. this paper presents 2 studies, conducted from 2007-2010, that examine thermal e ...201122176348
sensitivity and specificity of histology for diagnoses of four common pathogens and detection of nontarget pathogens in adult chinook salmon (oncorhynchus tshawytscha) in fresh water.histology is often underutilized in aquatic animal disease screening and diagnostics. the agreement between histological classifications of infection and results using diagnostic testing from the american fisheries society's blue book was conducted with 4 common salmon pathogens: aeromonas salmonicida, renibacterium salmoninarum, ceratomyxa shasta, and nanophyetus salmincola. adult chinook salmon (oncorhynchus tshawytscha) in oregon were evaluated, and agreement between tests was calculated. liv ...201323536613
a survey of microparasites present in adult migrating chinook salmon (oncorhynchus tshawytscha) in south-western british columbia determined by high-throughput quantitative polymerase chain reaction.microparasites play an important role in the demography, ecology and evolution of pacific salmonids. as salmon stocks continue to decline and the impacts of global climate change on fish populations become apparent, a greater understanding of microparasites in wild salmon populations is warranted. we used high-throughput, quantitative pcr (ht-qrt-pcr) to rapidly screen 82 adult chinook salmon from five geographically or genetically distinct groups (mostly returning to tributaries of the fraser r ...201728188649
mapping rainbow trout immune genes involved in inflammation reveals conserved blocks of immune genes in teleosts.we report the genetic map location of 14 genes involved in the inflammatory response to salmonid bacterial and viral pathogens, which brings the total number of immune genes mapped in rainbow trout (rt, oncorhynchus mykiss) to 61. these genes were mapped as candidate genes that may be involved in resistance to bacterial kidney disease, as well as candidates for known qtl for resistance to infectious hematopoietic necrosis virus, infectious pancreatic necrosis virus and ceratomyxa shasta. these q ...201323013476
identification of a novel ccr7 gene in rainbow trout with differential expression in the context of mucosal or systemic mammals, ccr7 is the chemokine receptor for the ccl19 and ccl21 chemokines, molecules with a major role in the recruitment of lymphocytes to lymph nodes and peyer's patches in the intestinal mucosa, especially naïve t lymphocytes. in the current work, we have identified a ccr7 orthologue in rainbow trout (oncorhynchus mykiss) that shares many of the conserved features of mammalian ccr7. the receptor is constitutively transcribed in the gills, hindgut, spleen, thymus and gonad. when leukocyte ...201222858409
erection of ceratonova n. gen. (myxosporea: ceratomyxidae) to encompass freshwater species c. gasterostea n. sp. from threespine stickleback (gasterosteus aculeatus) and c. shasta n. comb. from salmonid fishes.ceratonova gasterostea n. gen. n. sp. is described from the intestine of freshwater gasterosteus aculeatus l. from the klamath river, california. myxospores are arcuate, 22.4 ± 2.6 μm thick, 5.2 ± 0.4 μm long, posterior angle 45° ± 24°, with 2 sub-spherical polar capsules, diameter 2.3 ± 0.2 μm, which lie adjacent to the suture. its ribosomal small subunit sequence was most similar to an intestinal parasite of salmonid fishes, ceratomyxa shasta (97%, 1,671/1,692 nucleotides), and distinct from a ...201424754344
molecular evidence of undescribed ceratonova sp. (cnidaria: myxosporea) in the freshwater polychaete, manayunkia speciosa, from western lake erie.we used pcr to screen pooled individuals of manayunkia speciosa from western lake erie, michigan, usa for myxosporean parasites. amplicons from positive pcrs were sequenced and showed a ceratonova species in an estimated 1.1% (95% ci=0.46%, 1.8%) of m. speciosa individuals. we sequenced 18s, its1, 5.8s, its2 and most of the 28s rdna regions of this ceratonova sp., and part of the protein-coding ef2 gene. phylogenetic analyses of ribosomal and ef2 sequences showed the lake erie ceratonova sp. is ...201627150245
evolutionary origin of ceratonova shasta and phylogeny of the marine myxosporean order to clarify the phylogenetic relationships among the main marine myxosporean clades including newly established ceratonova clade and scrutinizing their evolutionary origins, we performed large-scale phylogenetic analysis of all myxosporean species from the marine myxosporean lineage based on three gene analyses and statistical topology tests. furthermore, we obtained new molecular data for ceratonova shasta, c. gasterostea, eight ceratomyxa species and one myxodavisia species. we describ ...201525797924
capture severity, infectious disease processes and sex influence post-release mortality of sockeye salmon bycatch.bycatch is a common occurrence in heavily fished areas such as the fraser river, british columbia, where fisheries target returning adult pacific salmon (oncorhynchus spp.) en route to spawning grounds. the extent to which these encounters reduce fish survival through injury and physiological impairment depends on multiple factors including capture severity, river temperature and infectious agents. in an effort to characterize the mechanisms of post-release mortality and address fishery and mana ...201728852514
myxobolus arcticus and parvicapsula minibicornis infections in sockeye salmon oncorhynchus nerka following downstream migration in british columbia.factors influencing the health of sockeye salmon oncorhynchus nerka in british columbia, canada, are important for fisheries management and conservation. juvenile salmon originating from the fraser river were screened for 3 enzootic parasites (myxobolus arcticus, parvicapsula minibicornis, ceratonova shasta) and the bacterium renibacterium salmoninarum. fish were collected from the strait of georgia in 2010, 2011 and 2012 and genotyped to stock of origin. trends in infection status were estimate ...201729044039
functional and proteomic analysis of ceratonova shasta (cnidaria: myxozoa) polar capsules reveals adaptations to parasitism.myxozoa is a diverse, speciose group of microscopic parasites, recently placed within the phylum cnidaria. myxozoans are highly reduced in size and complexity relative to free-living cnidarians, yet they have retained specialized organelles known as polar capsules, akin to the nematocyst stinging capsules of free-living species. whereas in free-living cnidarians the stinging capsules are used for prey capture or defense, in myxozoans they have the essential function of initiating the host infect ...201728827642
production of ceratonova shasta myxospores from salmon carcasses: carcass removal is not a viable management option.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 ...201627064587
immunity to gastrointestinal microparasites of intestinal parasites cause direct mortalities and also morbidity, poor growth, higher susceptibility to opportunistic pathogens and lower resistance to stress. this review is focused on microscopic parasites (protozoa and metazoa) that invade the gastrointestinal tract of fish. intracellular parasites (mainly microsporidia and apicomplexa) evoke almost no host immune reaction while they are concealed in the cytoplasmic and nuclear compartments, and can even use fish cells (macrophages) as t ...201626828391
lack of protection following re-exposure of chinook salmon to ceratonova shasta (myxozoa).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 ...201525494609
transmission and persistence of ceratonova shasta genotypes in chinook salmon.ceratonova shasta is a myxozoan parasite of salmon and trout transmitted by waterborne actinospores. based on dna sequence data and host specificity, 4 distinct parasite genotypes are recognized. genotypes i and ii are common in the lower reaches of the klamath river, oregon-california, but only infection by genotype i causes mortality in chinook salmon. we conducted sentinel fish exposures and determined genotype composition in river water during exposure, and in fish gills, intestine, and tank ...201424945751
post-mortem sporulation of ceratomyxa shasta (myxozoa) after death in adult chinook salmon.ceratomyxa shasta (myxozoa) is a common gastrointestinal pathogen of salmonid fishes in the pacific northwest of the united states. we have been investigating this parasite in adult chinook salmon ( oncorhynchus tshawytscha ) in the willamette river, oregon. in prior work, we observed differences in the pattern of development of c. shasta in adult salmon compared to juvenile salmon. adult salmon consistently had large numbers of prespore stages in many of the fish that survived to spawn in the f ...201424725089
defenses of susceptible and resistant chinook salmon (oncorhynchus tshawytscha) against the myxozoan parasite ceratomyxa shasta.we investigated intra-specific variation in the response of salmon to infection with the myxozoan ceratomyxa shasta by comparing the progress of parasite infection and measures of host immune response in susceptible and resistant chinook salmon oncorhynchus tshawytscha at days 12, 25 and 90 post exposure. there were no differences in invasion of the gills indicating that resistance does not occur at the site of entry. in the intestine on day 12, infection intensity and ig(+) cell numbers were hi ...201424412163
biology and mucosal immunity to myxozoans.myxozoans are among the most abundant parasites in nature. their life cycles involve two hosts: an invertebrate, usually an annelid, and a vertebrate, usually a fish. they affect fish species in their natural habitats but also constitute a menace for fish aquaculture. using different strategies they are able to parasitize and cause damage in multiple organs, including mucosal tissues, which they use also as portals of entry. in fish, the main mucosal sites include the intestine, skin and gills. ...201423994774
estimation of transmission dynamics of the ceratomyxa shasta actinospore to the salmonid host.transmission dynamics of the actinospore stage of ceratomyxa shasta to the salmonid host were investigated under field and laboratory conditions. the number of parasites transmitted and the transmission rate were compared between 2 different exposure durations and also among different water velocities, by means of field exposures. under laboratory conditions, the number of parasites transmitted and the transmission rates were compared across a broader range of water velocities and also at differ ...201323506996
predicted redistribution of ceratomyxa shasta genotypes with salmonid passage in the deschutes river, oregon.a series of dams on the deschutes river, oregon, act as migration barriers that segregate the river system into upper and lower basins. proposed fish passage between basins would reunite populations of native potamodromous fish and allow anadromous fish of deschutes river origin access to the upper basin. we assessed the potential redistribution of host-species-specific genotypes (o, i, ii, iii) of the myxozoan parasite ceratomyxa shasta that could occur with fish passage and examined the influe ...201223146111
ceratomyxa shasta genotypes cause differential mortality in their salmonid hosts.ceratomyxa shasta is a myxozoan parasite of salmonid fish. in natural communities, distinct genotypes of the parasite are associated with different salmonid hosts. to test the hypothesis that genotypes of c. shasta cause differential mortality, the polychaete host was experimentally infected with different parasite genotypes. genotype i was obtained from chinook salmon, oncorhynchus tshawytscha, and genotype ii from either coho salmon, o. kisutch, or rainbow trout, o. mykiss, we then challenged ...201222808922
relationship between temperature and ceratomyxa shasta -induced mortality in klamath river salmonids.water temperature influences almost every biological and physiological process of salmon, including disease resistance. in the klamath river (california), current thermal conditions are considered sub-optimal for juvenile salmon. in addition to borderline temperatures, these fish must contend with the myxozoan parasite ceratomyxa shasta , a significant cause of juvenile salmonid mortality in this system. this paper presents 2 studies, conducted from 2007 to 2010, that examine thermal effects on ...201222746389
density of the waterborne parasite ceratomyxa shasta and its biological effects on salmon.the myxozoan parasite ceratomyxa shasta is a significant pathogen of juvenile salmonids in the pacific northwest of north america and is limiting recovery of chinook (oncorhynchus tshawytscha) and coho (o. kisutch) salmon populations in the klamath river. we conducted a 5-year monitoring program that comprised concurrent sentinel fish exposures and water sampling across 212 river kilometers of the klamath river. we used percent mortality and degree-days to death to measure disease severity in fi ...201222407689
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