| effects of whirling disease on selected hematological parameters in rainbow trout. | hematological responses to whirling disease in rainbow trout (oncorhynchus mykiss) were investigated. two-mo-old fingerling rainbow trout were exposed to cultured triactinomyxon spores of myxobolus cerebralis at 9,000 spores/fish in december, 1997. twenty-four wks post-exposure, fish were taken from infected and uninfected groups for peripheral blood and cranial tissue sampling. histological observations on cranial tissues confirmed m. cerebralis infection in all exposed fish. differences in hem ... | 2001 | 11310892 |
| ultraviolet irradiation inactivates the waterborne infective stages of myxobolus cerebralis: a treatment for hatchery water supplies. | the effects of ultraviolet (uv) irradiation on the viability of the waterborne triactinomyxon stages of myxobolus cerebralis were evaluated by vital staining and the infectivity for juvenile rainbow trout oncorhynchus mykiss. a dose of 1300 mws cm-2 was required to inactivate 100% of the triactinomyxons held under a static collimated beam of uv as determined by vital staining. juvenile rainbow trout were protected from infections with m. cerebralis when exposed to 14,000 or 1400 triactinomyxon s ... | 2000 | 10986645 |
| myxobolus cerebralis infection in rainbow trout (oncorhynchus mykiss) and brown trout (salmo trutta) exposed under natural stream conditions. | from early april into mid-june 1977, sequential groups of juvenile rainbow trout (oncorhynchus mykiss) and brown trout (salmo trutta) were each exposed for 10 days to the parasite myxobolus cerebralis by immersion in a stream inhabited by infected wild trout. following incubation in a m. cerebralis-free facility, trout were subsequently killed, and heads and gill arches were examined by routine histologic methods. a grading scale to quantify lesion severity was developed and applied. percentage ... | 2000 | 10907859 |
| comparative susceptibility of rainbow trout oncorhynchus mykiss and brown trout salmo trutta to myxobolus cerebralis, the cause of salmonid whirling disease. | the susceptibility of rainbow trout oncorhynchus mykiss and brown trout salmo trutta to myxobolus cerebralis, the cause of salmonid whirling disease, was assessed following dosed exposures to the infectious stages (triactinomyxons). parallel groups of age-matched brown trout and rainbow trout were exposed to 10, 100, 1000 or 10,000 triactinomyxons per fish for 2 h and then placed in aquaria receiving single pass 15 degrees c well water. severity of infection was evaluated by presence of clinical ... | 1999 | 10546047 |
| detection of early developmental stages of myxobolus cerebralis in fish and tubificid oligochaete hosts by in situ hybridization. | the myxosporean and actinosporean spores of myxobolus cerebralis develop through many stages in their respective hosts, salmonid fishes and a tubificid oligochaete. using a modified, non-radioactive in situ hybridization protocol, the parasite, which exhibits radically different structural forms during its development in each host, could be specifically detected in paraffin-embedded tissues of both fish and oligochaetes. our study aims to demonstrate the application of the technique for detectio ... | 1999 | 10540957 |
| effect of water temperature on the development, release and survival of the triactinomyxon stage of myxobolus cerebralis in its oligochaete host. | the development of the triactinomyxon stage of myxobolus cerebralis and release of mature spores from tubifex tubifex were shown to be temperature dependent. in the present work, the effect of temperature over a range of 5-30 degrees c on the development and release of the triactinomyxon stages of m. cerebralis was studied. infected t. tubifex stopped releasing triactinomyxon spores 4 days after transfer from 15 degrees c to 25 degrees c or 30 degrees c. transmission electron microscopic examina ... | 1999 | 10428640 |
| comparison of 18s and its-1 rdna sequences of selected geographic isolates of myxobolus cerebralis. | myxobolus cerebralis, the myxosporean parasite-causing salmonid whirling disease, was first reported among rainbow trout (oncorhynchus mykiss) in germany in 1903. the parasite was reported for the first time in north america in 1958 among hatchery-reared trout in the eastern usa, presumably arriving with frozen trout shipments from europe. a comparison of 18s and its-1 ribosomal dna sequences was conducted to identify potential strain differences between selected geographic isolates of this para ... | 1999 | 10404274 |
| relationships among members of the genus myxobolus (myxozoa: bilvalvidae) based on small subunit ribosomal dna sequences. | sequences representing approximately 1,700 base pairs of the 18s rrna gene from 10 different species in the genus myxobolus were found to group them into 3 clusters that showed little correlation with spore morphology and size or host specificity, criteria currently used for both higher and lower taxonomic placements in the myxozoa. of the phenotypic criteria examined, tissue tropism was most correlated with the rrna groupings observed. spores of similar size and shape (myxobolus cerebralis vs. ... | 1999 | 10207366 |
| whirling disease: host specificity and interaction between the actinosporean stage of myxobolus cerebralis and rainbow trout oncorhynchus mykiss. | scanning electron microscopic studies were conducted on rainbow trout oncorhynchus mykiss in the first 60 min after their exposure to the triactinomyxon spores of myxobolus cerebralis. the results demonstrated that as early as 1 min post exposure the whole process, from the attachment of the triactinomyxon spores to the complete penetration of their sporoplasm germs, had occurred. the triactinomyxon spores sought out the secretory openings of mucous cells of the epidermis, the respiratory epithe ... | 1999 | 10073310 |
| whirling disease: re-emergence among wild trout. | whirling disease of rainbow trout is caused by myxobolus cerebralis, a myxozoan parasite possessing a life cycle well adapted to the natural environments where salmonid fish are found. whirling disease was first described in europe in 1898 among farmed rainbow trout but recent occurrences have been devastating to wild trout in north america. the disease is considered a major threat to survival of wild rainbow trout in the intermountain west of the united states. difficulties in containing the sp ... | 1998 | 9914926 |
| a nested polymerase chain reaction for the detection of genomic dna of myxobolus cerebralis in rainbow trout oncorhynchus mykiss. | a nested polymerase chain reaction (pcr) test was developed to amplify a segment of the 18s rrna gene from myxobolus cerebralis, the agent causing whirling disease in salmonid fish. the pcr amplifies a 415 bp amplicon that was identified by dideoxynucleotide terminated sequencing to be identical to the known 18s rdna sequence of m. cerebralis. there was no amplification of genomic dna from 4 other myxosporean parasites of salmonid fish from the genus myxobolus including m. arcticus, m. insidiosu ... | 1998 | 9828408 |
| determination of nuclear dna concentration in cells of myxobolus cerebralis and triactinomyxon spores, the causative agent of whirling disease. | myxobolus cerebralis (myxozoa: myxosporea) has a complex two-host life cycle, which begins when waterborne triactinomyxon spores released from the infected oligochaete tubifex tubifex contact a susceptible trout. upon contact the triactinomyxon spores attach to the fish and release their sporoplasm cells into the epidermis. at approximately 50 days postinfection, sporogenesis begins, resulting in a large number of m. cerebralis spores in the cartilage of infected fish 6 weeks later. the spores o ... | 1998 | 9766896 |
| myxobolus cerebralis in tubifex tubifex from a whirling disease epizootic in montana. | aquatic oligochaetes from a whirling disease enzootic area in southwest montana were examined for infection with myxobolus cerebralis. anterior portions of oligochaetes were preserved for specific identification, whereas dna was purified from posterior portions. the purified dna was used in a nested polymerase chain reaction (pcr) assay specific for m. cerebralis small-subunit ribosomal dna. naturally infected oligochaetes were identified by a resulting 415-bp fragment of amplified parasite dna. ... | 1998 | 9714199 |
| light and electron microscopic studies on the chronological development of myxobolus cerebralis to the actinosporean stage in tubifex tubifex. | whirling disease caused by myxobolus cerebralis has become the most widely known disease of salmonids in the 1990s. in the last 5 years we have studied many aspects regarding the host-pathogen relationship of this parasite. the parasite's histozoic development causes significant damage to cartilage and induces cns symptoms by pressure on the brain and spinal cord. myxobolus cerebralis has a two-host life-cycle involving a salmonid fish and a tubificid oligochaete. two different stages of sporogo ... | 1998 | 9504346 |
| small subunit ribosomal rna sequences unite alternate actinosporean and myxosporean stages of myxobolus cerebralis the causative agent of whirling disease in salmonid fish. | the alternating myxosporean and actinosporean stages of the myxozoan parasite myxobolus cerebralis (hofer 1903) from its salmonid fish and aquatic oligochaete hosts, respectively, were compared for sequence homology of the small subunit (18s) ribosomal rna genes. a 99.8% similarity between the sequences of these two stages was substantially greater than that of m. cerebralis compared to two other myxobolus sp. from salmonid fish. our results are the first molecular evidence confirming the altern ... | 1997 | 9183708 |
| [new details of the life cycle of myxobolus cerebralis according to the literature]. | the article comprises new details of the life cycle of myxobolus cerebralis, the parasite of the skeleton of salmonids. although this species has been known since 1903, its complete life cycle has remained unknown till now or it has comprised mistaken details. recently el matbouli et al. (1995) have described the life cycle of this parasite with numerous new data. m. cerebralis provokes in salmonids (especially in rainbow trouts) the whirling disease and heavy economical losses. therefore the ar ... | 1996 | 9012131 |
| evaluation of five diagnostic methods for the detection and quantification of myxobolus cerebralis. | diagnostic methods were used to identify and quantify myxobolus cerebralis, a myxozoan parasite of salmonid fish. in this study, 7-week-old, pathogen-free rainbow trout (oncorhynchus mykiss) were experimentally infected with m. cerebralis and at 7 months postinfection were evaluated with 5 diagnostic assays: 1) pepsin-trypsin digest (ptd) to detect and enumerate spores found in cranial cartilage, 2) 2 different histopathology grading scales that provide a numerical score for severity of microsco ... | 2004 | 15152834 |
| [new data on some parasitic invasions in fish]. | the author gives a review of new literature data from the 80-ties. the following problems are considered: etiology of swim bladder inflammation in carp (sbi), development of parasites of the class myxosporea, overgrowth of parasitic kidney disease (pkd) in salmonid fishes, details of development of myxobolus cerebralis and ichthyophtirius multifiliis, and the new systematics of the diplozoidae. | 1989 | 2699131 |
| new trends in parasitic infections of cultured freshwater fish. | the 1980s are characterized by the appearance of new fish parasitoses, the clarification of the aetiology of diseases and new insights into the process of infection and the development of important parasites, especially myxosporidians. two phaerosporoses have entered into the foreground: swimbladder inflammation (sbi) caused by sphaerospora renicola in common carp and proliferative kidney disease (pkd) in salmonids. both diseases must be reported in the german democratic republic (gdr). the conn ... | 1989 | 2669320 |
| factors influencing the distribution of myxobolus cerebralis, the causative agent of whirling disease, in the cache la poudre river, colorado. | oligochaetes, triactinomyxons (tams), and age-0 trout were sampled in the upper cache la poudre river, colorado, to determine the distribution of myxobolus cerebralis during 1997 and 1998. densities of the intermediate host, the oligochaete tubifex tubifex, were 3.5 orders of magnitude higher in the m. cerebralis-infected poudre rearing unit (pru) trout rearing ponds than at any of the river sampling reaches. oligochaetes, including t. tubifex, were rare in the river (1 oligochaete m(-2)), excep ... | 2002 | 12093042 |
| evaluation of nested polymerase chain reaction, pepsin/trypsin digest, and histology for the detection of myxobolus cerebralis in salmonid fishes of indiana and michigan. | the objectives of this study were to survey fish from state hatcheries in indiana and michigan and to compare the nested polymerase chain reaction (pcr) test with pepsin/trypsin digest (ptd) and histopathology for the diagnosis of whirling disease (wd). one group of 40 and 9 groups of 60 fish heads, for a total of 580 samples, were submitted from hatcheries in indiana and michigan. these samples were examined for myxozoan spores using histopathology, ptd, and pcr tests. the heads were hemisectio ... | 2002 | 12033684 |
| 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 ... | 2001 | 11602199 |
| comparison of single-round polymerase chain reaction (pcr) and pepsin-trypsin digest (ptd) methods for detection of myxobolus cerebralis. | single-round polymerase chain reaction (pcr) and pepsin-trypsin digest (ptd) methods were compared for the detection of myxobolus cerebralis. parallel tests were conducted on a total of 1743 free-ranging and 400 hatchery-reared salmonids. concurrent results were found in 84.6% of the free-ranging fish samples, and 83.5% of the hatchery samples. pcr identified m. cerebralis more frequently than did ptd, and did so in many geographic locations previously considered free of the parasite. average my ... | 2001 | 11463097 |
| recent advances in our knowledge of the myxozoa. | in 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 ... | 2001 | 11456316 |
| molecular phylogeny of tubificid oligochaetes with special emphasis on tubifex tubifex (tubificidae). | tubifex tubifex is a cosmopolitan freshwater oligochaete whose presence has been studied as a health indicator of the aquatic environment and as a host for several myxozoan parasites of fish. unfortunately, current morphological criteria used to distinguish tubifex spp. (tubificidae) are inadequate. we therefore developed mitochondrial 16s ribosomal dna markers to examine phylogenetic relationships among aquatic oligochaetes and to distinguish species of tubifex that might serve as hosts for a p ... | 2001 | 11341804 |
| the effects of myxobolus cerebralis myxospore dose on triactinomyxon production and biology of tubifex tubifex from two geographic regions. | the aquatic oligochaete tubifex tubifex is an obligate host of myxobolus cerebralis, the causative agent of salmonid whirling disease. tubifex tubifex can become infected by ingesting myxospores of m. cerebralis that have been released into sediments upon death and decomposition of infected salmonids. infected worms release triactinomyxons into the water column that then infect salmonids. how the dose of myxospores ingested by t. tubifex influences parasite proliferation and the worm host are no ... | 2001 | 11318561 |
| persistent infection of myxobolus cerebralis, the causative agent of salmonid whirling disease, in tubifex tubifex. | the objective of this study was to quantify and determine the periodicity in the release of the triactinomyxon (tam) stage of myxobolus cerebralis, the causative agent of salmonid whirling disease, by its aquatic oligochaete host tubifex tubifex. for this, 24 individual t. tubifex (infected as a group at 15 c) were examined daily for the release of m. cerebralis tams, and the number of waterborne tams released by each worm was quantified. the duration of the infection in these worms was also mon ... | 2001 | 11227872 |
| response of rainbow trout oncorhynchus mykiss to exposure to myxobolus cerebralis above and below a point source of infectivity in the upper colorado river. | we exposed 9 wk old rainbow trout oncorhynchus mykiss to ambient levels of myxobolus cerebralis infectious stages at 4 sites of suspected differing infectivity in the colorado river. exposure was estimated by periodic filtration of river water at each exposure location. after a 32 d exposure, the fish were held in the colorado river at a common site for over a year. resulting infection was evaluated by the presence of clinical signs (whirling behavior, cranial deformity/exophthalmia, and black t ... | 2002 | 12113302 |
| validation of a single round polymerase chain reaction assay for identification of myxobolus cerebralis myxospores. | validation of a single round pcr-based assay to confirm as myxobolus cerebralis myxospores obtained from pepsin-trypsin digest preparations is described. the assay is a modification of a pcr assay published previously, based on the amplification of a segment of the gene encoding the 18s ribosomal subunit of m. cerebralis. the sensitivity, specificity and upper and lower detection limits were determined using known m. cerebralis and non-m. cerebralis myxospores and m. cerebralis-free fish. the se ... | 2002 | 12113304 |
| prevalence and susceptibility of infection to myxobolus cerebralis, and genetic differences among populations of tubifex tubifex. | the prevalence of infection and susceptibility of the aquatic oligochaete tubifex tubifex to myxobolus cerebralis, was examined in 2 studies on the upper colorado river, colorado, usa, where whirling disease occurs in wild trout populations. in the first study, the prevalence of infection ranged from 0.4 to 1.5%, as determined by counting the number of t. tubifex releasing triactinomyxons of m. cerebralis directly following their collection from the field. the susceptibility of those t. tubifex ... | 2002 | 12363083 |
| study of the tail fin rays of rainbow trout (oncorhynchus mykiss) infected with the parasite myxobolus cerebralis. | a light, transmission and scanning microscope study of the rays (lepidotrichia) forming the tail fin of rainbow trout (oncorhynchus mykiss) fingerlings infected with the parasite myxobolus cerebralis showed that triactinomyxon adherence to the tail fin of host fingerlings occurred 10 min after infection. after 2 h of exposure, it was possible to observe triactinomyxon spores in the epidermis. although the characteristic symptoms of the disease, such as a black tail and a change in tail morpholog ... | 2002 | 12408363 |
| physical and chemical effects on viability of the myxobolus cerebralis triactinomyxon. | various chemical and physical methods for destroying the triactinomyxon (tam) stage of the myxozoan parasite myxobolus cerebralis were tested. the fluorescent stains propidium iodide and fluorescein diacetate were used as indicators of viability. physical variables tested included freezing, drying, high temperature, sonication, and pressure of 6.2 x 10(7) pa (9000 psi). chemicals evaluated included chlorine bleach, povidone-iodine, and hydrogen peroxide. freezing or drying for 1 h was effective ... | 2003 | 12650246 |
| effects of water temperature and substrate type on spore production and release in eastern tubifex tubifex worms infected with myxobolus cerebralis. | eastern tubifex tubifex worms were exposed to myxobolus cerebralis spores at 9, 13, 17, and 20 c in 1-l jars that contained sand, mud, or leaf litter as substrata. beginning 60 days after exposure, water from each jar was filtered daily and examined for the presence of waterborne triactinomyxon spores (tams). on discovering a single tam from an experimental jar, 48 t. tubifex worms from that jar were placed individually into 24-well plates. spores released from individual infected t. tubifex wor ... | 2003 | 12659298 |
| detection of myxozoan parasites in oligochaetes imported as food for ornamental fish. | to determine the potential for dissemination of myxozoan parasites by transfer of their alternate oligochaete hosts, shipments of tubificid worms obtained from an overseas commercial aquarium supplier were screened for actinospore stages of myxozoan parasites. at least 7 different triactinomyxon types were identified. the morphological characteristics of the actinospores recovered from these tubificids shared characteristics with triactinomyxons characterized in other surveys, particularly from ... | 2003 | 12659308 |
| detection of early stages of myxobolus cerebralis in fin clips from rainbow trout (orynchus mykiss). | a nested polymerase chain reaction (pcr) assay was used to detect early stages of myxobolus cerebralis in caudal and adipose fin samples from rainbow trout (rt). to determine sensitivity, groups of 10 rt were exposed to 2,000 m. cerebralis triactinomyxons/fish for 1 hour at 15 degrees c and subsequently moved to clean recirculating water. fish were held for 2 and 6 hours and 1, 2, 3, 5, 7, 10, 30, and 60 days before sampling by nonlethal fin biopsy. nested pcr performed on fin clips showed that ... | 2006 | 16789717 |
| susceptibility of two strains of rainbow trout (one with suspected resistance to whirling disease) to myxobolus cerebralis infection. | the susceptibility of 2 strains of rainbow trout oncorhynchus mykiss, 1 from north america (tl) and 1 from germany (gr), to myxobolus cerebralis (the cause of salmonid whirling disease) was assessed following exposure to the infectious stages (triactinomyxons). two laboratory experiments were conducted with age-matched rainbow trout of each strain. at the beginning of the study, the 2 trout strains were aged ca. 570 degree-days in expt 1, and ca. 999 degree-days in expt 2. in both experiments, r ... | 2003 | 12887253 |
| histologic study of head cartilage degeneration in rainbow trout (oncorhynchus mykiss) infected with the parasite myxobolus cerebralis. | a light microscopy study of head cartilage tissue in rainbow trout alevins (oncorhynchus mykiss) infected with the parasite myxobolus cerebralis showed that, regardless of the presence or absence of whirling disease symptoms such as black tail and whirling swimming due to altered tail and spine morphology, some fish presented large amounts of spores lodged in the head after three months of infection. the spores were located in regions where the cartilage was extensively destroyed. | 2003 | 12974324 |
| evaluation of a range of doses of ultraviolet irradiation to inactivate waterborne actinospore stages of myxobolus cerebralis. | the ability of a range of doses of ultraviolet irradiation (uv) to inactivate the waterborne actinospore or triactinomyxon stages (tams) of myxobolus cerebralis was evaluated by infectivity for juvenile rainbow trout oncorhynchus mykiss. tams were uv-irradiated using a low pressure mercury vapour lamp collimated beam apparatus. all doses 40, 80, 120 and 160 mj cm(-2) were found to completely inactivate the tams as demonstrated by the absence of microscopic lesions, myxospores and parasite dna de ... | 2007 | 17432040 |
| whirling disease of salmonid fish: life cycle, biology, and disease. | myxobolus cerebralis is the myxozoan parasite responsible for causing whirling disease in salmonid fish. although the parasite was first described nearly 100 yr ago, it received relatively little attention until the discovery of its 2-host life cycle in the mid 1980s. this was the first, complete, myxozoan life cycle to be described, and it was greeted with some skepticism because it united 2 stages of m. cerebralis that were previously classified in 2 separate taxa. in the last decade, there ha ... | 2003 | 14533670 |
| relative quantification of immune-regulatory genes in two rainbow trout strains, oncorhynchus mykiss, after exposure to myxobolus cerebralis, the causative agent of whirling disease. | expression of immune-regulatory genes that code for cyclooxigenase-2 (cox-2), transforming growth factor beta (tgf-beta), and two isoforms of interleukin-1beta (il-1beta1 and il-1beta2) was studied in susceptible and non-susceptible rainbow trout strains for 200 days after exposure to myxobolus cerebralis. expression of cox-2, il-1beta1, and il-1beta2 increased 5 min post exposure (p.e.) and was always more elevated in the susceptible strain than in the non-susceptible strain. in both strains, e ... | 2007 | 17530478 |
| sds-page and western blot analysis of triactinomyxon spores of myxobolus cerebralis, the cause of whirling disease in salmonid fish. | | 2003 | 14653320 |
| efficacy of passive sand filtration in reducing exposure of salmonids to the actinospore of myxobolus cerebralis. | the aquatic oligochaete tubifex tubifex parasitized by myxobolus cerebralis releases triactinomyxon (tam) actinospores that can infect some species of salmonids and cause salmonid whirling disease. silica sand was tested as a filtration medium for removal of tams from water containing the parasite. laboratory tests indicated sand filtration removed > 99.99% of tams. in 2 different field tests, groups of 1 mo old rainbow trout oncorhynchus mykiss were exposed for 2 wk to filtered and unfiltered w ... | 2003 | 14735924 |
| myxobolus cerebralis: identification of a cathepsin z-like protease gene (myxcp-1) expressed during parasite development in rainbow trout, oncorhynchus mykiss. | cysteine proteases are essential to the biological function of parasitic organisms and are gaining interest as the target of chemotherapeutics aimed at their control. we report a cysteine protease gene from the myxozoan myxobolus cerebralis, the cause of whirling disease in salmonid fish. the mature gene (myxcp-1) encodes a 248-amino acid polypeptide that includes catalytic residues similar to the papain family of cysteine proteases. myxcp-1 features a propeptide region and sequence insertions t ... | 2003 | 14990313 |
| comparative susceptibility of atlantic salmon, lake trout and rainbow trout to myxobolus cerebralis in controlled laboratory exposures. | the susceptibility of lake trout salvelinus namaycush, rainbow trout oncorhynchus mykiss and atlantic salmon salmo salar to myxobolus cerebralis, the causative agent of whirling disease, was compared in controlled laboratory exposures. a total of 450 (225 for each dose) fry for each species were exposed to a low (200 spores per fish) or high (2000 spores per fish) dose of the infective triactinomyxon. at 22 wk post-exposure, 60 fish from each group, as well as controls for each species, were exa ... | 2004 | 15038448 |
| myxobolus cerebralis internal transcribed spacer 1 (its-1) sequences support recent spread of the parasite to north america and within europe. | molecular approaches for resolving relationships among the myxozoa have relied mainly on small subunit (ssu) ribosomal dna (rdna) sequence analysis. this region of the gene is generally used for higher phylogenetic studies, and the conservative nature of this gene may make it inadequate for intraspecific comparisons. previous intraspecific studies of myxobolus cerebralis based on molecular analyses reported that the sequence of ssu rdna and the internal transcribed spacer (its) were highly conse ... | 2004 | 15460854 |
| real-time quantitative polymerase chain reaction (qpcr) to identify myxobolus cerebralis in rainbow trout oncorhynchus mykiss. | this study describes the development of a taqman real-time quantitative polymerase chain reaction (qpcr) technique using the heat-shock protein 70 (hsp 70) and 18s ribosomal dna (18s rdna) sequences to identify myxobolus cerebralis and attempt to quantify infection severity within rainbow trout fry oncorhynchus mykiss. rainbow trout for this study were exposed to m. cerebralis under natural river conditions and examined for infection by histology, polymerase chain reaction (pcr) and qpcr analysi ... | 2004 | 15521319 |
| phylogenetic comparison of the myxosporea based on an actin cdna isolated from myxobolus cerebralis. | the full-length actin gene from myxobolus cerebralis (mceract-1), the first characterized from representatives in the phylum myxozoa, encodes a 378-amino acid polypeptide with an estimated molecular weight of 41,580-da. a phylogenetic comparison found m. cerebralis to branch outside the metazoans. this finding contrasts with previous reports that suggest an evolutionary affinity of the myxozoa with either the bilateria or cnidaria. | 2004 | 15666723 |
| differential propagation of the metazoan parasite myxobolus cerebralis by limnodrilus hoffmeisteri, ilyodrilus templetoni, and genetically distinct strains of tubifex tubifex. | whirling disease, caused by the parasite myxobolus cerebralis, has infected rainbow trout (oncorhynchus mykiss) and other salmonid fish in the western united states, often with devastating results to native populations but without a discernible spatial pattern. the parasite develops in a complex 2-host system in which the aquatic oligochaete tubifex tubifex is an obligate host. because substantial differences in whirling disease severity in different areas of north america did not seem explainab ... | 2004 | 15715230 |
| tubifex tubifex from alaska and their susceptibility to myxobolus cerebralis. | although widespread throughout the continental united states, myxobolus cerebralis, the myxozoan parasite that causes whirling disease in salmonids, has not been reported from the state of alaska. as part of a risk assessment for the introduction and establishment of m. cerebralis into alaska, the distribution of the invertebrate host tubifex tubifex was surveyed, and its genetic composition and susceptibility to the parasite were determined. many oligochaetes, but no t. tubifex, were collected ... | 2007 | 18314677 |
| effects of fish age versus size on the development of whirling disease in rainbow trout. | we examined the effects of both fish age and size on the development of resistance to whirling disease in erwin strain rainbow trout. previously, we demonstrated that juvenile rainbow trout became resistant to development of the disease when first exposed to triactinomyxons of the parasite myxobolus cerebralis at about 9 wk post-hatch when raised at 12 degrees c, but ages and sizes of fish used in that experiment were confounded (ryce ekn, zale av, macconnell e [2004] dis aquat org 59:225-233). ... | 2005 | 15759802 |
| lectin blot studies on proteins of myxobolus cerebralis, the causative agent of whirling disease. | it is known that myxobolus cerebralis antigens, both surficial and secreted, are key modulators for, or targets of, host immune system compounds. we undertook sds-page glycoprotein characterisation of m. cerebralis developmental stages isolated from infected rainbow trout and western blot analyses using selected biotin-labelled plant lectins (gsa-i, pha-e, sja, gsa-ii) and anti-triactinomyxon polyclonal antibodies. glycoproteins were isolated with lectin-affinity chromatography, and prominent ba ... | 2005 | 16119891 |
| characterisation of carbohydrate-binding sites in developmental stages of myxobolus cerebralis. | glycans and lectins (carbohydrate-binding molecules) form a mutual recognition system, which enables parasitic organisms to attach themselves to the host cells and/or take part in the migration of their developmental stages into the target tissue. the aim of the present study was to identify and characterise the potential binding activity of glycoconjugates in different developmental stages of myxobolus cerebralis, the causative agent of whirling disease in salmonids. the binding patterns of 13 ... | 2005 | 16211413 |
| polar filament discharge of myxobolus cerebralis actinospores is triggered by combined non-specific mechanical and chemical cues. | this study presents initial evidence for the requirement of both chemical and mechanical stimuli to discharge polar capsules of myxobolus cerebralis actinospores, the causative agent of salmonid whirling disease. the obligate need for combined discharge triggers was concluded from data obtained in a before/after experimental set-up carried out with individual locally immobilized actinospores. homogenized rainbow trout mucus as chemostimulus and tangency of the apical region of the spores to achi ... | 2005 | 16255819 |
| development of a rapid assay for the diagnosis of myxobolus cerebralis in fish and oligochaetes using loop-mediated isothermal amplification. | a loop-mediated isothermal amplification assay was developed for the rapid detection of myxobolus cerebralis in both fish and oligochaete hosts. the assay was optimized to amplify parasitic dna by incubation with bst dna polymerase and a set of six specially constructed primers at 65 degrees c for 60 min. the amplification products were detected visually using sybr green i dye which gave identical results to gel electrophoresis analysis. parasite dna was detected from infected oligochaetes, and ... | 2005 | 16266328 |
| the effect of cohabitation of tubifex tubifex (oligochaeta: tubificidae) populations on infections to myxobolus cerebralis (myxozoa: myxobolidae). | the competitive interactions between susceptible and resistant tubifex tubifex (oligochaeta: tubificidae) exposed to myxobolus cerebralis (myxozoa: myxobolidae) infections were investigated in two laboratory trials. competition was assessed by the total parasite production over the course of the trials in mixed and pure cultures of m. cerebralis exposed worms, and by the genetic analyses of worms from the control and experimental groups at the beginning and end of the experiments. mixed cultures ... | 2006 | 16321396 |
| construction and screening of a cdna library from the triactinomyxon spores of myxobolus cerebralis, the causative agent of salmonid whirling diseases. | the zap express cdna library was constructed using mrna extracted from the triactinomyxon spores of myxobolus cerebralis. first-strand cdna was synthesized using moloney murine leukaemia virus reverse transcriptase. following second-strand cdna synthesis, the double-stranded cdna was digested with xho i restriction enzyme, cdna fragments less than 400 bp were removed and the remaining cdna was ligated with the lambda zap express vector. the recombinants were packaged in vitro using gigapack iii ... | 2006 | 16388692 |
| interactions among two strains of tubifex tubifex (oligochaeta: tubificidae) and myxobolus cerebralis (myxozoa). | host-parasite interactions influence host population growth, host evolution and parasite success. we examined the interactions among myxobolus cerebralis, the parasite that causes salmonid whirling disease, and resistant and susceptible strains of the oligochaete host tubifex tubifex. strains of t. tubifex with diverse genotypes often coexist in nature and have variable susceptibilities to m. cerebralis infection. further, parasite proliferation differs by several orders of magnitude among t. tu ... | 2006 | 16532604 |
| evaluation of quantitative real-time pcr for rapid assessments of the exposure of sentinel fish to myxobolus cerebralis. | pathogen-free rainbow trout (oncorhynchus mykiss) aged 735 degree days were experimentally exposed to a low dose of infectious myxobolus cerebralis (20 triactinomyxons fish(-1)). three time periods were chosen for sampling that included 10 days (d), 67 d, and 5 months (mo) post exposure. five diagnostic assays were used: (1) conventional single-round polymerase chain reaction (pcr), (2) nested pcr, (3) real-time taqman pcr, (4) pepsin-trypsin digest, and (5) histopathology. m. cerebralis was det ... | 2006 | 16555100 |
| risk of myxobolus cerebralis infection to rainbow trout in the madison river, montana, usa. | myxobolus cerebralis, the parasite that causes salmonid whirling disease, has had detrimental effects on several salmonid populations in the intermountain west, including the rainbow trout in the madison river, montana, usa. the goal of this study was to examine relationships among characteristics of the environment, tubifex tubifex (the alternate host) populations, and rainbow trout whirling disease risk in the madison river. environmental characteristics were measured in side channels of the m ... | 2006 | 16711061 |
| propagation of the myxozoan parasite myxobolus cerebralis by different geographic and genetic populations of tubifex tubifex: an oregon perspective. | tubifex tubifex are obligate invertebrate hosts in the life cycle of myxobolus cerebralis, the myxozoan parasite that causes whirling disease in salmonid fishes. this exotic parasite is established to varying degrees across oregon's columbia river system (pacific northwest, usa) and characteristics of local t. tubifex populations likely play a role in the pattern of disease occurrence. to better understand these patterns, we collected t. tubifex from three oregon river basins (willamette, deschu ... | 2009 | 19583968 |
| epizootiology of myxobolus cerebralis, the causative agent of salmonid whirling disease in the rock creek drainage of west-central montana: 2004-2008. | whirling disease, caused by the myxozoan parasite myxobolus cerebralis , remains a serious health threat to salmonid fish in the western united states. a previously published study on the epizootiology of whirling disease in the rock creek watershed of west-central montana, conducted from 1998 to 2003, showed that the intensity of m. cerebralis infections in sentinel trout increased significantly throughout the drainage and that the range of m. cerebralis had expanded considerably. in addition, ... | 2010 | 19891515 |
| myxobolus cerebralis infection patterns in yellowstone cutthroat trout after natural exposure. | salmonid species and sub-species exhibit a range of susceptibility to myxobolus cerebralis infection. little is known about lesion severity and location, or time required for m. cerebralis myxospores to develop in yellowstone cutthroat trout oncorhynchus clarki bouvieri. in 2002 we performed three 10 d exposures of yellowstone cutthroat trout fry in pelican creek, an m. cerebralis-positive tributary to yellowstone lake. at 90 and 150 d post-exposure we examined the fish for clinical signs, for i ... | 2006 | 17058600 |
| isolation of a subtilisin-like serine protease gene (myxsubtsp) from spores of myxobolus cerebralis, the causative agent of whirling disease. | proteases play important roles in parasite life cycles and host-parasite interactions. they are pathogenesis factors of many pathogenic organisms and are hence potential targets for chemotherapeutic treatment of disease. we identified a subtilisin-like serine protease gene, myxsubtsp, expressed by myxobolus cerebralis. after pcr with subtilisin-like serine protease primers, the gene was cloned, sequenced and aligned against the ncbi database. its corresponding amino acid sequence included the pu ... | 2007 | 17330744 |
| epizootiology of myxobolus cerebralis, the causative agent of salmonid whirling disease in the rock creek drainage of west-central montana. | whirling disease, caused by the myxozoan parasite myxobolus cerebralis, remains a health threat to salmonid fish in the western united states. although various aspects of this host-parasite system have been studied, investigations examining the overall epizootiology of whirling disease in an ecosystem are lacking. therefore, in june 1998, studies were initiated in the rock creek watershed of west-central montana and continued through 2003 to assess the intensity of infection in trout using senti ... | 2007 | 17436949 |
| expanded geographical distribution of myxobolus cerebralis: first detections from alaska. | the parasite responsible for salmonid whirling disease, myxobolus cerebralis, was introduced to the usa in 1958. it has since spread across the country causing severe declines in wild trout populations, but has never been documented from alaska. however, while assessing the risk of introduction of m. cerebralis into the state, we detected the parasite using a species-specific polymerase chain reaction (pcr) assay. testing of 180 hatchery rainbow trout, oncorhynchus mykiss (walbaum), by pepsin tr ... | 2007 | 17640251 |
| myxozoan transmission via actinospores: new insights into mechanisms and adaptations for host invasion. | various mechanisms that enable and improve transmission success of myxozoan actinospore stages towards fish hosts are described, based upon a combination of experimental data and functional analysis of morphological characters. for this purpose, laboratory-reared actinospores of myxobolus cerebralis, myxobolus parviformis, henneguya nuesslini and myxobolus pseudodispar were employed to exemplarily investigate aspects of host attachment and invasion. the process of polar filament discharge of m. ... | 2007 | 17662162 |
| effects of fish age and parasite dose on the development of whirling disease in rainbow trout. | we determined the ages at which juvenile rainbow trout oncorhynchus mykiss became resistant to the effects of whirling disease following exposure to a range of parasite doses. heretofore, the development and severity of whirling disease in salmonids was known to be generally dependent on the age or size of fish when first exposed to the triactinomyxon spores of myxobolus cerebralis; larger, older individuals tended to be less diseased. however, no systematic determination had been made of the ex ... | 2004 | 15264719 |
| identification of a serine protease gene expressed by myxobolus cerebralis during development in rainbow trout oncorhynchus mykiss. | serine proteases have been recognized as key factors in parasite physiology and disease development. we have identified a serine protease gene from myxobolus cerebralis, myxsp-1, the myxozoan parasite causing whirling disease in salmonid fishes. the amino acid sequence, as deduced from the cdna sequence, included a catalytic residue arrangement similar to that of the chymotrypsin family of serine proteases. a real-time taqman polymerase chain reaction (pcr) analysis revealed differences in the t ... | 2004 | 15264720 |
| extensive release of an antigen associated with the sporogonic stages of myxobolus cerebralis (myxozoa: myxosporea) is detected by a heterologous antibody raised to tetracapsuloides bryosalmonae (myxozoa: malacosporea). | monoclonal antibody b4 (mab b4) was previously developed to the myxozoan parasite tetracapsuloides bryosalmonae canning, curry, feist, longshaw et okamura, 1999, the causative agent of proliferative kidney disease of salmonids, here we describe the reaction of mab b4 against myxobolus cerebralis hofer, 1903, the parasite that causes 'whirling disease' in salmonids. tissues examined were collected from experimentally infected rainbow trout oncorhynchus mykiss (walbaum) and the aquatic oligochaete ... | 2004 | 15357400 |
| effects of water flow on the infection dynamics of myxobolus cerebralis. | myxobolus cerebralis, the myxozoan parasite responsible for whirling disease in salmonid fishes, has a complex life-cycle involving an invertebrate host and 2 spore stages. water flow rate is an environmental variable thought to affect the establishment and propagation of m. cerebralis; however, experimental data that separates flow effects from those of other variables are scarce. to compare how this parameter affected parasite infection dynamics and the invertebrate and vertebrate hosts, dead, ... | 2008 | 18053292 |
| discovery of genes implicated in whirling disease infection and resistance in rainbow trout using genome-wide expression profiling. | whirling disease, caused by the pathogen myxobolus cerebralis, afflicts several salmonid species. rainbow trout are particularly susceptible and may suffer high mortality rates. the disease is persistent and spreading in hatcheries and natural waters of several countries, including the u.s.a., and the economic losses attributed to whirling disease are substantial. in this study, genome-wide expression profiling using cdna microarrays was conducted for resistant hofer and susceptible trout lodge ... | 2008 | 18218127 |
| use of site occupancy models to estimate prevalence of myxobolus cerebralis infection in trout. | empirical estimates of pathogen prevalence in samples of fish may underestimate true prevalence because available detection techniques are incapable of perfect detection. trout of several species were collected from enzootic (myxobolus cerebralis, causative agent in whirling disease) habitats, and individual fish were examined for presence of the parasite two or six times by one of four methods: pepsin-trypsin digest (brown trout salmo trutta), plankton centrifuge (brown trout), polymerase chain ... | 2007 | 18236627 |
| a packed-bed filtration system for collection of myxobolus cerebralis triactinomyxons. | information on the distribution and abundance of myxobolus cerebralis triactinomyxons in natural systems is limited because direct and accurate sampling methods for this life stage have not been developed. existing methods are based on indirect measures of triactinomyxon densities and are therefore confounded. direct estimation of triactinomyxon concentrations would more exactly pinpoint the ambient infection risk to wild fish and allow evaluation of management strategies designed to mitigate th ... | 2007 | 18333480 |
| a new species of myxozoan (myxosporea) from the brain and spinal cord of rainbow trout (oncorhynchus mykiss) from idaho. | a new species of myxosporea, myxobolus neurotropus n. sp., is described from the brain and spinal cord of rainbow trout (oncorhynchus mykiss) from duncan creek, owyhee county, idaho. spores are oval, have 2 pyriform polar capsules, and possess a thick spore wall (sutural rim) with a short intracapsular offshoot. the mean spore dimensions are length 11.8 microm, width 10.8 microm, and thickness 8.8 microm. this myxozoan is compared to other described myxobolus species found in cranial tissues of ... | 2008 | 18372644 |
| 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. | 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), an ... | 2008 | 18605778 |
| differences in viability and reactivity of actinospores of three myxozoan species upon ageing. | little is known about the viability of myxozoan actinospore stages after harvest from laboratory cultures of infected oligochaete worms. the viability and reactivity of actinospores of three myxozoan species was evaluated after short-term storage at 4 degrees c and 12 degrees c. two methods of determining actinospore viability were compared: differential fluorescent staining and direct microscopic observation of morphological indicators of spore integrity. spore reactivity was quantified by meas ... | 2008 | 18666413 |
| effects of freezing, drying, ultraviolet irradiation, chlorine, and quaternary ammonium treatments on the infectivity of myxospores of myxobolus cerebralis for tubifex tubifex. | the effects of freezing, drying, ultraviolet irradiation (uv), chlorine, and a quaternary ammonium compound on the infectivity of the myxospore stage of myxobolus cerebralis (the causative agent of whirling disease) for tubifex tubifex were examined in a series of laboratory trials. freezing at either -20 degrees c or -80 degrees c for a period of 7 d or 2 months eliminated infectivity as assessed by the absence of production of the actinospore stage (triactinomyxons [tams]) from t. tubifex cult ... | 2008 | 18783133 |
| potential for dissemination of the nonnative salmonid parasite myxobolus cerebralis in alaska. | myxobolus cerebralis, the myxozoan parasite responsible for whirling disease in salmonids, was first introduced into the united states in 1958 and has since spread across the country, causing severe declines in wild trout populations in the intermountain western united states. the recent detection of the parasite in alaska is further evidence of the species' capability to invade and colonize new habitat. this study qualitatively assesses the risk of further spread and establishment of m. cerebra ... | 2008 | 18942590 |
| differentially expressed parasite genes involved in host recognition and invasion of the triactinomyxon stage of myxobolus cerebralis (myxozoa). | the host recognition and invasion process of myxobolus cerebralis actinospores (triactinomyxon, tam) was studied on a genetic level. a small-scale in vitro assay was developed to activate a large number of tams simultaneously, and to monitor the host invasion in the absence of live fish. the transcriptomes of non-activated and in vitro-activated tams were compared by suppressive subtractive hybridization (ssh) to identify parasite genes involved in the host invasion process. differential screeni ... | 2009 | 19195410 |
| myxobolus cerebralis (myxozoa), the causative agent of whirling disease, reduces fecundity and feeding activity of tubifex tubifex (oligochaeta). | myxobolus cerebralis is the causative agent of whirling disease that has significant economical and ecological impacts on trout populations. although intensive studies have been conducted to understand its effects on and interactions with its fish host, only limited information is available about how and to what extent m. cerebralis affects its oligochaete host, tubifex tubifex. we investigated the effects of m. cerebralis on survival, growth, reproduction, and feeding activity of t. tubifex. ma ... | 2009 | 19284888 |
| the life cycle of myxobolus lentisuturalis (myxozoa: myxobolidae), from goldfish (carassius auratus auratus), involves a raabeia-type actinospore. | we studied a natural infection of the oligochaete branchiura sowerbyi beddard, 1892 with the raabeia-type actinosporean stage of myxobolus lentisuturalis dyková, fiala et nie, 2002 which infected goldfish carassius auratus auratus (l.) in italy, using molecular analysis of the ssu rrna gene. the existence of intraoligochaete development shows that this parasite follows the life-cycle pattern described by wolf and markiw (1984) for myxobolus cerebralis. histological examinations of the goldfish i ... | 2009 | 19391327 |
| in vivo exposure of susceptible and non-susceptible fish species to myxobolus cerebralis actinospores reveals non-specific invasion behaviour. | due to controversial previous results, it has been unclear whether myxobolus cerebralis (myxosporea, myxozoa) is able to specifically choose a salmonid host by selective attachment and penetration. using a novel in vivo tracking assay that employs fluorescence staining of actinospore sporoplasms, we demonstrate a lack of host specificity of m. cerebralis actinospores during their initial invasion reactions. fish were experimentally exposed to stained actinospores that could be detected as emitte ... | 2009 | 19476282 |
| expression of immune-regulatory genes, arginase-2 and inducible nitric oxide synthase (inos), in two rainbow trout (oncorhynchus mykiss) strains following exposure to myxobolus cerebralis. | the present endeavor was conducted to evaluate the role of activated macrophage in the susceptibility of two different rainbow trout (oncorhynchus mykiss) strains, a susceptible american (t) and a more resistant german (h), to infection with myxobolus cerebralis. arginase-2 and inducible nitric oxide synthase (inos) genes were used as references to the alternative and classical pathway of macrophage activation. the expression level of both genes was measured using quantitative real-time polymera ... | 2010 | 19894064 |
| effect of cadmium on the susceptibility of tubifex tubifex to myxobolus cerebralis (myxozoa), the causative agent of whirling disease. | environmental pollutants alter a wide range of host-parasite interactions in various ways. in some cases, pollution leads to a significant increase in parasite abundance, causing epidemics of parasitic diseases. in other cases, toxicants restrict the transmission success of parasites, resulting in reduction of their abundance. however, very little is known regarding whether and to what extent aquatic pollution affects myxozoan obligate parasites commonly found in fish. we investigated the effect ... | 2010 | 20391913 |
| the effects of myxobolus cerebralis on apache and gila trout in laboratory exposures. | whirling disease has been implicated in salmonid population declines in several western states. to determine the risk of a species or strain of salmonid to whirling disease it is critical to establish its relative susceptibility to myxobolus cerebralis infection. gila trout oncorhynchus gilae and apache trout oncorhynchus gilae apache were exposed to various doses of m. cerebralis triactinomyxons (tams) in laboratory experiments. in trials conducted in consecutive years, fish were exposed to tam ... | 2010 | 20848882 |
| a major effect quantitative trait locus for whirling disease resistance identified in rainbow trout (oncorhynchus mykiss). | whirling disease, caused by the pathogen myxobolus cerebralis, leads to skeletal deformation, neurological impairment and under certain conditions, mortality of juvenile salmonid fishes. the disease has impacted the propagation and survival of many salmonid species over six continents, with particularly negative consequences for rainbow trout. to assess the genetic basis of whirling disease resistance in rainbow trout, genome-wide mapping was initiated using a large outbred f(2) rainbow trout fa ... | 2010 | 21048672 |
| analysis of rainbow trout oncorhynchus mykiss epidermal mucus and evaluation of semiochemical activity for polar filament discharge in myxobolus cerebralis actinospores. | as myxozoan actinospores are stimulated by fish epidermal mucus to attach to their hosts via extrusion of filaments from specialized organelles, the polar capsules, mucus components were tested for discharge triggering activity on myxobolus cerebralis actinospores. using various methodological approaches, a selective exclusion of candidate substances based on experimental outcome is provided and the physiochemical traits of the putative agents are explored to create a basis for the isolation of ... | 2010 | 21078020 |
| no shot in the dark: myxozoans chemically detect fresh fish. | this work reports the discovery of an hitherto unknown chemical recognition trait enabling a parasitic life cycle in aquatic habitats. we believe this is the first record of a natural, host-derived chemical molecule identified as a recognition cue for the phylum myxozoa. the actinospores of these parasites attach to fish hosts via polar filaments that are extruded upon mechanical stimulation after preceding recognition of a chemical trigger contained in surface mucus. our goal was to identify th ... | 2010 | 21087611 |
| inosine-arginine salt as a promising agent for in vitro activation of waterborne fish-pathogenic myxozoan actinospores. | mucus-derived nucleosides serve as key host cues for myxozoan actinospore fish host recognition, but to date their use for experimental actinospore activation in the laboratory or application in disease prevention has not progressed very far. one obstacle has been the low solubility of pure inosine and guanosine. to overcome this, we used inosine-arginine salt (ino-arg), which incorporates both high activation properties and high solubility. we tested its efficacy both in microassays directly ob ... | 2014 | 24991742 |
| sequence analysis of omnramp alpha and quantitative expression of nramp homologues in different trout strains after infection with myxobolus cerebralis. | salmonid whirling disease caused by the metazoan parasite myxobolus cerebralis is an ongoing problem in wild and farmed rainbow trout oncorhynchus mykiss populations. rainbow trout from different strains vary in susceptibility to the parasite. identification of underlying mechanisms could be a starting point for improved control of the disease. we conducted infection trials using 2 rainbow trout strains and brown trout salmo trutta fario, a species not susceptible to the parasite, to investigate ... | 2007 | 17803108 |
| arrested development of the myxozoan parasite, myxobolus cerebralis, in certain populations of mitochondrial 16s lineage iii tubifex tubifex. | laboratory populations of tubifex tubifex from mitochondrial (mt)16s ribosomal dna (rdna) lineage iii were generated from single cocoons of adult worms releasing the triactinomyxon stages (tams) of the myxozoan parasite, myxobolus cerebralis. subsequent worm populations from these cocoons, referred to as clonal lines, were tested for susceptibility to infection with the myxospore stages of m. cerebralis. development and release of tams occurred in five clonal lines, while four clonal lines showe ... | 2008 | 17891544 |
| characterization of glycans in the developmental stages of myxobolus cerebralis (myxozoa), the causative agent of whirling disease. | glycans and sugar-binding molecules (lectins) form an interactive recognition system, which may enable parasitic organisms to adhere to host cells and migrate into target tissues. the aim of the present study was to analyse surface-associated glycans in the developmental stages of myxobolus cerebralis (hofer), the causative agent of whirling disease. a panel of biotin-labelled plant lectins was used to detect a broad spectrum of glycan motifs with high specificity. binding sites were detected hi ... | 2007 | 17958607 |
| the parasite that causes whirling disease, myxobolus cerebralis, is genetically variable within and across spatial scales. | understanding the genetic structure of parasite populations on the natural landscape can reveal important aspects of disease ecology and epidemiology and can indicate parasite dispersal across the landscape. myxobolus cerebralis (myxozoa: myxosporea), the causative agent of whirling disease in the definitive host tubifex tubifex, is native to eurasia and has spread to more than 25 states in the usa. the small amounts of data available to date suggest that m. cerebralis has little genetic variabi ... | 2011 | 22151695 |
| the effects of myxobolus cerebralis on the physiological performance of whirling disease resistant and susceptible strains of rainbow trout. | the development of rainbow trout oncorhynchus mykiss strains that are resistant to whirling disease has shown promise as a management tool for populations in areas where myxobolus cerebralis is present. however, the physiological effects of the disease on characteristics necessary for fish survival in natural river conditions have not been tested in many of these strains. five rainbow trout strains were evaluated for their swimming ability and growth characteristics in relation to m. cerebralis ... | 2011 | 22372244 |
| genetic basis of differences in myxospore count between whirling disease-resistant and susceptible strains of rainbow trout. | we used a quantitative genetics approach and estimated broad sense heritability (h2b) of myxospore count and the number of genes involved in myxospore formation to gain a better understanding of how resistance to myxobolus cerebralis, the parasite responsible for whirling disease, is inherited in rainbow trout oncorhynchus mykiss. an m. cerebralis-resistant strain of rainbow trout, the german rainbow (gr), and a wild, susceptible strain of rainbow trout, the colorado river rainbow (crr), were sp ... | 2012 | 23269384 |
| counter-insurgents of the blue revolution? parasites and diseases affecting aquaculture and science. | aquaculture is the fastest-growing segment of food production and is expected to supply a growing portion of animal protein for consumption by humans. because industrial aquaculture developed only recently compared to industrial agriculture, its development occurred within the context of a growing environmental awareness and acknowledgment of environmental issues associated with industrial farming. as such, parasites and diseases have become central criticisms of commercial aquaculture. this foc ... | 2014 | 25260074 |
| myxobolus cerebralis (hofer) infection risk in native cutthroat trout oncorhynchus clarkii (richardson) and its relationships to tributary environments in the yellowstone lake basin. | conservation of native species is challenged by the introduction of non-native pathogens and diseases into aquatic and terrestrial environments worldwide. in the yellowstone lake basin, yellowstone national park, the invasive parasite causing salmonid whirling disease myxobolus cerebralis (hofer) has been identified as one factor contributing to population declines of native yellowstone cutthroat trout oncorhynchus clarkii bouvieri (jordan & gilbert). in 2002 and 2003, we examined relationships ... | 2015 | 24953674 |
| susceptibility to myxobolus cerebralis among tubifex tubifex populations from ten major drainage basins in colorado where cutthroat trout are endemic. | establishment of myxobolus cerebralis (mc) resulted in declines of wild rainbow trout oncorhynchus mykiss populations in streams across colorado during the 1990s. however, the risk for establishment and spread of this parasite into high-elevation habitats occupied by native cutthroat trout o. clarkii was unknown. beginning in 2003, tubificid worms were collected from all major drainages where cutthroat trout were endemic and were assayed by quantitative pcr to determine the occurrence and distri ... | 2014 | 24689955 |
| analysis of regional scale risk of whirling disease in populations of colorado and rio grande cutthroat trout using a bayesian belief network model. | introduction and spread of the parasite myxobolus cerebralis, the causative agent of whirling disease, has contributed to the collapse of wild trout populations throughout the intermountain west. of concern is the risk the disease may have on conservation and recovery of native cutthroat trout. we employed a bayesian belief network to assess probability of whirling disease in colorado river and rio grande cutthroat trout (oncorhynchus clarkii pleuriticus and oncorhynchus clarkii virginalis, resp ... | 2014 | 24660663 |
| comparison of hatchery and field performance between a whirling-disease-resistant strain and the ten sleep strain of rainbow trout. | a whirling-disease-resistant strain of rainbow trout oncorhynchus mykiss (grhl strain) derived from a backcross of an f1 hybrid of two strains (german strain x harrison lake strain) with german strain females, was compared with the ten sleep (ts) strain of rainbow trout. the grhl strain had consistently superior growth and feed conversion in two consecutive hatchery trials. hatching and mortality rates were similar between strains. both strains were stocked into two utah reservoirs (hyrum, porcu ... | 2012 | 22838082 |