| a comparison of two methods for colorimetric in situ hybridization using paraffin-embedded tissue sections and digoxigenin-labeled hybridization probes. | two methods for colorimetric in situ dna probe hybridization (cish) assays on paraffin-embedded tissue sections were compared. the heated method used heat (90-100°c) to denature dna in the sample prior to probe hybridization, while the unheated method used a standard hybridization temperature of 42°c. both procedures were tested on tissue samples that harbored the mollusk protozoan pathogens perkinsus marinus, p. chesapeaki, or haplosporidium nelsoni, the protozoan and bacterial fish pathogens m ... | 2013 | 23697605 |
| 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 |
| biostatic activity of piscine serum and mucus on myxozoan fish infective stages. | since the basis of host specificity in myxozoa, i.e. the differential disposition and extinction of erroneously penetrated myxozoan infective stages in non-susceptible fish hosts, remains puzzling, we aimed to explore the role of the innate immune system in this issue. in a comparative incubation challenge of actinospore sporoplasms of the freshwater parasite species myxobolus cerebralis, henneguya nuesslini and myxobolus pseudodispar to isolates of host and non-host muci and blood sera, we meas ... | 2012 | 22951229 |
| morphological and molecular confirmation of myxobolus cerebralis myxospores infecting wild‑caught and cultured trout in north carolina (se usa). | we used microscopy and molecular biology to provide the first documentation of infections of myxobolus cerebralis (myxozoa: myxobolidae), the etiological agent of whirling disease, in trout (salmonidae) from north carolina (usa) river basins. a total of 1085 rainbow trout oncorhynchus mykiss, 696 brown trout salmo trutta, and 319 brook trout salvelinus fontinalis from 43 localities across 9 river basins were screened. myxospores were observed microscopically in pepsin-trypsin digested heads of r ... | 2017 | 29160217 |
| the impact of tetracapsuloides bryosalmonae and myxobolus cerebralis co-infections on pathology in rainbow trout. | myxozoan parasites pose emerging health issues for wild and farmed salmonid fish. rainbow trout (oncorhynchus mykiss) is a particularly susceptible species to tetracapsuloides bryosalmonae (malacosporea), the etiological agent of proliferative kidney disease (pkd), and to myxobolus cerebralis (myxosporea), the etiological agent of whirling disease (wd). the objective of this study was to investigate the impact of myxozoan co-infections on the pathogenesis of pkd and wd in the rainbow trout. | 2017 | 28946913 |
| 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 |
| temporal expression patterns of rainbow trout immune-related genes in response to myxobolus cerebralis exposure. | infection of salmonids by the myxozoan parasite myxobolus cerebralis can cause whirling disease, which is responsible for high mortalities in rainbow trout hatcheries and natural populations in the united states. although considerable research has provided insight into disease pathology, host invasion, and inheritance patterns of resistance, the causal genetic variants and molecular mechanisms underlying host resistance or susceptibility remain elusive. a previous study found that expression cha ... | 2013 | 23867493 |
| reduced myxobolus cerebralis actinospore production in a colorado reservoir may be linked to changes in tubifex tubifex population structure. | elucidating the dynamics of a parasitic infection requiring two hosts in a natural ecosystem can be a daunting task. myxobolus cerebralis (mc), the myxozoan parasite that causes whirling disease in some salmonids, was detected in the colorado river upstream of windy gap reservoir (wgr) in 1988. subsequently, whirling disease was implicated in the decline of wild rainbow trout oncorhynchus mykiss in the river when wgr was identified as a point source of mc triactinomyxons (tams). between 1997 and ... | 2013 | 23944286 |
| whirling disease revisited: pathogenesis, parasite biology and disease intervention. | whirling disease (wd) is an ecologically and economically debilitating disease of rainbow trout oncorhynchus mykiss caused by the actinosporean spores of the parasite myxobolus cerebralis. m. cerebralis has a complex, 2-host life cycle alternating between salmonid fish and the oligochaete host tubifex tubifex. the parasite alternates between 2 spore forms as transmission stages: an actinosporean triactinomyxon spore that is produced in the oligochaete host and a myxosporean spore that develops i ... | 2015 | 25993890 |
| parental genetic diversity of brown trout (salmo trutta m. fario) brood stock affects offspring susceptibility to whirling disease. | whirling disease, caused by the myxozoan parasite myxobolus cerebralis, has high economical and ecological importance worldwide. susceptibility to the disease varies considerably among salmonid species. in brown trout (salmo trutta) the infection is usually subclinical with low mortality, which increases the risk of parasite dissemination, especially when farm fish are used for stocking natural habitats. the influence of intraspecific genetic differences (especially the level of homozygosity) on ... | 2015 | 25886048 |
| agent of whirling disease meets orphan worm: phylogenomic analyses firmly place myxozoa in cnidaria. | myxozoa are microscopic obligate endoparasites with complex live cycles. representatives are myxobolus cerebralis, the causative agent of whirling disease in salmonids, and the enigmatic "orphan worm" buddenbrockia plumatellae parasitizing in bryozoa. originally, myxozoa were classified as protists, but later several metazoan characteristics were reported. however, their phylogenetic relationships remained doubtful. some molecular phylogenetic analyses placed them as sister group to or even with ... | 2013 | 23382916 |
| myxobolus neurotropus infecting rainbow trout in alaska, a new geographic record. | the alaska department of fish and game fish pathology laboratory received a rainbow trout oncorhynchus mykiss from the alaska peninsula that was suspected of having whirling disease based on the display of aberrant swimming behavior and a deformed spine. we tested for myxobolus cerebralis using standard pepsin-trypsin digest and molecular procedures, which yielded negative results. however, many oval shaped myxospores were observed in brain smears and were confirmed to be those of the morphologi ... | 2012 | 23066815 |
| spatial and temporal variation of whirling disease risk in montana spring creeks and rivers. | spring creeks are important spawning and rearing areas for wild trout, but the stable flows, cool temperatures, and high nutrient levels that characterize these unique habitats may also make them highly susceptible to establishment and proliferation of the whirling disease pathogen myxobolus cerebralis. we evaluated the spatial and temporal dynamics in whirling disease risk by using sentinel rainbow trout oncorhynchus mykiss fry in nine different spring creeks and their conjoining rivers or rese ... | 2012 | 23025590 |
| laboratory and hatchery-scale evaluation of sand filters and their efficacy at controlling whirling disease infection. | in two separate tests rapid sand filtration was evaluated as a means of removing the waterborne triactinomyxon actinospores (tams) of myxobolus cerebralis, the causative agent of salmonid whirling disease, from contaminated water. in the first test we independently evaluated two sizes of sandblast sands: #4010 (effective size, (es) = 250 μm) and #4060 (es = 300 μm). the product number relates to the sand's size composition, and each had a different effective size. effective size is defined by th ... | 2006 | 26599157 |
| a rnai-based therapeutic proof of concept targets salmonid whirling disease in vivo. | myxobolus cerebralis is a cnidarian-myxozoan parasite that causes salmonid whirling disease. m. cerebralis alternates between two hosts: (1) a vertebrate salmonid and (2) an invertebrate oligochaete, tubifex tubifex. there is no successful treatment for salmonid whirling disease. myxsp-1 is a m. cerebralis serine protease implicated in whirling disease pathogenesis. we hypothesized that short-interfering rna (sirna)-induced rna interference (rnai) can silence myxsp-1 in the invertebrate host and ... | 2017 | 28575083 |
| accelerated deactivation of myxobolus cerebralis myxospores by susceptible and non-susceptible tubifex tubifex. | in the 1990s, the tubifex tubifex aquatic oligochaete species complex was parsed into 6 separate lineages differing in susceptibility to myxobolus cerebralis, the myxozoan parasite that can cause whirling disease (wd). lineage iii t. tubifex oligochaetes are highly susceptible to m. cerebralis infection. lineage i, iv, v and vi oligochaetes are highly resistant or refractory to infection and may function as biological filters by deactivating m. cerebralis myxospores. we designed a 2-phased labor ... | 2016 | 27596858 |
| survival and reproduction of myxobolus cerebralis-resistant rainbow trout introduced to the colorado river and increased resistance of age-0 progeny. | myxobolus cerebralis caused severe declines in rainbow trout populations across colorado following its introduction in the 1980s. one promising approach for the recovery of colorado's rainbow trout populations has been the production of rainbow trout that are genetically resistant to the parasite. we introduced one of these resistant crosses, known as the gr×crr (cross between the german rainbow [gr] and colorado river rainbow [crr] trout strains), to the upper colorado river. the abundance, sur ... | 2014 | 24811066 |
| whirling disease dynamics: an analysis of intervention strategies. | whirling disease (wd), a severe and widespread disease of salmonids, is caused by the myxosporean parasite myxobolus cerebralis. it is further characterized by a unique two-host life cycle, utilizing the oligochaete tubifex tubifex as an intermediate host. m. cerebralis is an invasive species that has been affecting populations in the united states including epidemics that killed in excess of 90% of populations in colorado and montana streams within the past 20 years. currently, there is no know ... | 2014 | 24439792 |
| effects of habitat alteration on the epizootiology of myxobolus cerebralis, the causative agent of salmonid whirling disease. | whirling disease, caused by the myxozoan parasite myxobolus cerebralis , is a serious health threat to salmonid fish and its control remains problematic. the parasite has a 2-host life cycle involving a salmonid and the aquatic oligochaete tubifex tubifex . a commonly used strategy to control parasites that requires an obligatory invertebrate host is to eliminate or reduce the host population size to a point where parasite transmission can no longer occur. large numbers of t. tubifex are frequen ... | 2014 | 24383542 |
| using real-time pcr and bayesian analysis to distinguish susceptible tubificid taxa important in the transmission of myxobolus cerebralis, the cause of salmonid whirling disease. | aquatic oligochaetes have long been appreciated for their value in assessing habitat quality because they are ubiquitous sediment-dwelling filter feeders. many oligochaete taxa are also important in the transmission of fish diseases. distinguishing resistant and susceptible taxa is important for managing fish disease, yet challenging in practice. tubifex tubifex (oligochaeta: tubificidae) is the definitive host for the complex life-cycle parasite, myxobolus cerebralis, the causative agent of sal ... | 2013 | 23474394 |
| genomic insights into the evolutionary origin of myxozoa within cnidaria. | the myxozoa comprise over 2,000 species of microscopic obligate parasites that use both invertebrate and vertebrate hosts as part of their life cycle. although the evolutionary origin of myxozoans has been elusive, a close relationship with cnidarians, a group that includes corals, sea anemones, jellyfish, and hydroids, is supported by some phylogenetic studies and the observation that the distinctive myxozoan structure, the polar capsule, is remarkably similar to the stinging structures (nemato ... | 2015 | 26627241 |
| assessment of the long-term viability of the myxospores of myxobolus cerebralis as determined by production of the actinospores by tubifex tubifex. | while whirling disease was first observed in rainbow trout oncorhynchus mykiss in 1893, the complete life cycle of myxobolus cerebralis (mc), the causative agent of the disease, was not understood until 1984, when it was shown to involve two obligate hosts, a salmonid fish and the aquatic oligochaete tubifex tubifex (tt). the viability of the triactinomyxon (tam) actinospores produced by tt has been well studied, and is known to be temperature dependent and measured in days and weeks. assertions ... | 2015 | 26306333 |
| 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 |
| invasion and initial replication of ultraviolet irradiated waterborne infective stages of myxobolus cerebralis results in immunity to whirling disease in rainbow trout. | myxobolus cerebralis is a microscopic metazoan parasite (phylum myxozoa: myxosporea) associated with salmonid whirling disease. there are currently no vaccines to minimise the serious negative economical and ecological impacts of whirling disease among populations of salmonid fish worldwide. uv irradiation has been shown to effectively inactivate the waterborne infective stages or triactinomyxons of m. cerbralis in experimental and hatchery settings but the mechanisms by which the parasite is co ... | 2012 | 22580732 |
| rapid natural selection for resistance to an introduced parasite of rainbow trout. | introduced species and infectious diseases both independently pose challenges for the preservation of existing biodiversity. however, native species or disease hosts are by no means 'unarmed' when faced with novel environmental challenges, provided that adequate adaptive genetic variation exists to mount effective evolutionary responses. in this study, we examined the consequences of the recently introduced parasite and causative agent of whirling disease (myxobolus cerebralis) in a wild rainbow ... | 2008 | 25567635 |