Publications

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
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
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
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
[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