| molecular data implicate bryozoans as hosts for pkx (phylum myxozoa) and identify a clade of bryozoan parasites within the myxozoa. | proliferative kidney disease (pkd), a condition associated with high mortality in salmonid fish, represents an abnormal immune response to the presence of an enigmatic myxozoan, which has been designated simply as pkx organism because its generic and specific status are obscure. phylogenetic analyses of partial sequences of the 18s rdna of pkx and of myxozoan parasites infecting the bryozoans cristatella mucedo, pectinatella magnifica and plumatella rugosa, including the previously named tetraca ... | 1999 | 10633916 |
| ecology, development and pathogenicity of buddenbrockia plumatellae schröder, 1910 (myxozoa, malacosporea) (syn. tetracapsula bryozoides) and establishment of tetracapsuloides n. gen. for tetracapsula bryosalmonae. | buddenbrockia plumatellae, an enigmatic worm-like myxozoan, was observed as continuously writhing free and attached 'worms' and as free mature spores in the coelom of the freshwater bryozoans plumatella fungosa, hyalinella punctata, and fredericella sp. 'worm' numbers could double every three days. 'worms' and spores could be expelled from colonies by external pressure. some mature 'worms' exited actively, entraining release of free spores, and gradually ceased movement outside the host. bryozoa ... | 2002 | 12188218 |
| evaluation of malacosporean life cycles through transmission studies. | myxozoans, belonging to the recently described class malacosporea, parasitise freshwater bryozoans during at least part of their life cycle, but no complete malacosporean life cycle is known to date. one of the 2 described malacosporeans is tetracapsuloides bryosalmonae, the causative agent of salmonid proliferative kidney disease. the other is buddenbrockia plumatellae, so far only found in freshwater bryozoans. our investigations evaluated malacosporean life cycles, focusing on transmission fr ... | 2004 | 15460855 |
| sacculogenesis of buddenbrockia plumatellae (myxozoa) within the invertebrate host plumatella repens (bryozoa) with comments on the evolutionary relationships of the myxozoa. | members of the phylum myxozoa are obligate parasites, primarily of aquatic organisms. their phylogeny has remained problematic, with studies placing them within either the bilateria or cnidaria. the discovery that the enigmatic buddenbrockia plumatellae is a myxozoan that possesses distinct bilaterian features appeared to have finally resolved the debate. b. plumatellae is described as a triploblastic 'worm-like' organism, within which typical myxozoan malacospores form. using em we examined the ... | 2007 | 17434518 |
| origin and evolution of a myxozoan worm. | buddenbrockia plumatellae is an active, muscular, worm-shaped parasite of freshwater bryozoans. this rare and enigmatic animal has been assigned to the myxozoa on the basis of 18s ribosomal dna sequences and the presence of malacosporean spores. here we report cloning of four homologous protein-coding genes from buddenbrockia worms, the putatively conspecific sac-shaped parasite originally described as tetracapsula bryozoides and the related sac-shaped parasite tetracapsuloides bryosalmonae, the ... | 2007 | 21669756 |
| structural integrity and viability of fredericella sultana statoblasts infected with tetracapsuloides bryosalmonae (myxozoa) under diverse treatment conditions. | fredericella sultana is an invertebrate host of tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease in salmonids. the bryozoan produces seed-like statoblasts to facilitate its persistence during unfavourable conditions. statoblasts from infected bryozoans can harbor t. bryosalmonae and give rise to infected bryozoan colonies when conditions improve. we aimed in the present study to evaluate the integrity and viability of t. bryosalmonae-infected statoblasts after a ... | 2017 | 28381233 |
| sequence and expression analysis of two t helper master transcription factors, t-bet and gata3, in rainbow trout oncorhynchus mykiss and analysis of their expression during bacterial and parasitic infection. | the polarization of naïve cd4+ t cells to t helper (th)1 or th2 cells is specified by two master transcription factors, t-bet and gata3, and is an essential feature of mammalian adaptive immune responses to pathogens and the development of long-lasting immunity. we report here the cloning of rainbow trout oncorhynchus mykiss t-bet and gata3, to allow the future evaluation of the existence of th1 and th2 cells in salmonid fish. the trout t-bet translation shares high amino acid identities to othe ... | 2010 | 20633655 |
| comparison of the susceptibility of brown trout (salmo trutta) and four rainbow trout (oncorhynchus mykiss) strains to the myxozoan tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (pkd). | differences in susceptibility to the myxozoan parasite tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (pkd), between four strains of rainbow trout (oncorhynchus mykiss) and brown trout (salmo trutta) were evaluated. fish were exposed to water enzootic for the parasite in the field for 5 days and were subsequently transferred to the laboratory. relative parasite load was determined after 2, 3 and 4 weeks post-exposure (wpe) by quantitative real-time pcr (qpcr) ... | 2009 | 19683396 |
| an assessment of the variation in the prevalence of renal myxosporidiosis and hepatitis in wild brown trout, salmo trutta l., within and between rivers in south-west england. | the prevalence of renal myxosporidiosis in wild brown trout, salmo trutta, in seven river catchments in south-west england was investigated. three hundred and twenty-seven fish were sampled from 16 sites, of which 54 (16.5%) were found, by histological examination of the kidney, to be infected with tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease. no t. bryosalmonae infected fish were found in one river catchment, in other catchments the prevalence ranged from 2 ... | 2008 | 18681903 |
| sporogony of tetracapsuloides bryosalmonae in the brown trout salmo trutta and the role of the tertiary cell during the vertebrate phase of myxozoan life cycles. | tetracapsuloides bryosalmonae is the myxozoan that causes the commercially and ecologically important proliferative kidney disease of salmonid fish species. immunohistochemistry and electron microscopy were used to examine the development of this parasite within the kidney of the brown trout salmo trutta. the main replicative phase of t. bryosalmonae is a cell doublet composed of a primary cell and a single secondary cell. engulfment of one secondary cell by another to form a secondary-tertiary ... | 2008 | 18549518 |
| transmission of tetracapsuloides bryosalmonae (myxozoa: malacosporea) to fredericella sultana (bryozoa: phylactolaemata) by various fish species. | tetracapsuloides bryosalmonae is a myxozoan parasite of salmonids and freshwater bryozoans, which causes proliferative kidney disease (pkd) in the fish host. to test which fish species are able to transmit t. bryosalmonae to bryozoans, an infection experiment was conducted with 5 pkd-sensitive fish species from different genera. rainbow trout oncorhynchus mykiss, brown trout salmo trutta, brook trout salvelinus fontinalis, grayling thymallus thymallus and northern pike esox lucius were cohabitat ... | 2008 | 18500029 |
| severe mortality in wild atlantic salmon salmo salar due to proliferative kidney disease (pkd) caused by tetracapsuloides bryosalmonae (myxozoa). | extensive mortality in atlantic salmon fry was reported in the river aelva from 2002 to 2004. dead fish were collected in late summer 2006, and live fish were sampled by electrofishing in september the same year. at autopsy and in histological sections, the fish kidneys were found to be pale and considerably enlarged. proliferative lesions with characteristic pkx cells were seen in a majority of the fish. dna from kidney samples of diseased fish was subjected to pcr and sequencing, and the ampli ... | 2007 | 18062470 |
| transmission of tetracapsuloides bryosalmonae (myxozoa: malacosporea), the causative organism of salmonid proliferative kidney disease, to the freshwater bryozoan fredericella sultana. | proliferative kidney disease (pkd), caused by the malacosporean parasite tetracapsuloides bryosalmonae, causes significant losses among salmonids in western europe and north america. the role of salmonid fish in the life-cycle of this parasite has been conjectured upon for over a quarter of a century. to examine whether fish can transmit the infection to bryozoans, the known invertebrate host, water containing parasitized brown trout salmo trutta was pumped into tanks containing colonies of fred ... | 2006 | 16948873 |
| loop-mediated isothermal amplification: an emerging technology for detection of fish and shellfish pathogens. | fish and shellfish diseases are a constant threat to the sustainability and economic viability of aquaculture. early diagnosis plays a vital role in management of fish and shellfish diseases. traditionally, various biochemical and serological tests have been used for fish disease diagnosis. however, the time and expertise required for such diagnoses makes it difficult for aquaculturists to easily adopt them under production conditions. polymerase chain reaction and probe-based nucleic acid detec ... | 2005 | 16302951 |
| development of tetracapsuloides bryosalmonae (myxozoa: malacosporea) in bryozoan hosts (as examined by light microscopy) and quantitation of infective dose to rainbow trout (oncorhynchus mykiss). | the myxozoan parasite tetracapsuloides bryosalmonae is the causative agent of proliferative kidney disease (pkd), a highly damaging disease of cultured salmonid fish. within this study, phylactolaemate bryozoans were collected from a river known to be endemic for pkd and subsequently cultured in the laboratory. sequential developmental stages of t. bryosalmonae were studied by light microscopy within the living bryozoan colonies, allowing the identification of stages attached to host peritoneum, ... | 2006 | 16154706 |
| the morphology of tetracapsuloides bryosalmonae (myxozoa: malacosporea) spores released from fredericella sultana (bryozoa: phylactolaemata). | | 2005 | 15892757 |
| molecular studies on the seasonal occurrence and development of five myxozoans in farmed salmo trutta l. | five myxozoan species, tetracapsuloides bryosalmonae, sphaerospora truttae, chloromyxum schurovi, chloromyxum truttae and a myxobolus species were detected in farmed brown trout, salmo trutta l. from central scotland. using pcr and in situ hybridization, this study investigated the seasonal occurrence and tissue location of these species in young of the year brown trout. c. schurovi, c. truttae and myxobolus sp. were first detected in brown trout in april, 2 months before t. bryosalmonae and s. ... | 2006 | 16216135 |
| 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 |
| 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 |
| patterns of occurrence and 18s rdna sequence variation of pkx (tetracapsula bryosalmonae), the causative agent of salmonid proliferative kidney disease. | recent progress in understanding the etiology of proliferative kidney disease (pkd) includes the identification of freshwater bryozoans as the natural hosts of the myxozoan parasite that causes the disease in salmonid fish and formal description of the parasite as tetracapsula bryosalmonae. this paper presents data on patterns of occurrence of t. bryosalmonae and sequence variation among isolates. t. bryosalmonae infects bryozoans that range from primitive to more derived genera within the phyla ... | 2001 | 11318568 |
| review of myxosporea of importance in salmonid fisheries and aquaculture in british columbia. | several myxosporean parasites are of importance in fisheries and aquaculture in british columbia. the pkx organism and ceratomyxa shasta noble, 1950 cause disease and mortality, kudoa thyrsites (gilchrist, 1924) and henneguya salminicola ward, 1919 are of importance because they infect somatic muscle, cause unsightly cysts and soft flesh, and thus reduce the market value of the fish. myxobolus arcticus pugachev et khokhlov, 1979, an apparently non-pathogenic species, along with h. salminicola, i ... | 1994 | 8050752 |
| pkx, the causative agent of proliferative kidney disease (pkd) in pacific salmonid fishes and its affinities with the myxozoa. | proliferative kidney disease (pkd), caused by an unclassified protozoan (pkx), is reported from pacific salmon, oncorhynchus tshawytscha (walbaum) and o. kisutch (walbaum), and steelhead trout, salmo gairdneri richardson, held at the mad river hatchery in california, usa. the cumulative mortality attributed to the disease was 95, 13, and 18% respectively. the mortalities were greatest at mean water temperatures of 12-14 degrees c during july 1983. the ultrastructure of the pkx organism and its a ... | 1985 | 4009511 |
| vertical transmission of tetracapsuloides bryosalmonae (myxozoa), the causative agent of salmonid proliferative kidney disease. | the freshwater bryozoan, fredericella sultana, is the main primary host of the myxozoan endoparasite, tetracapsuloides bryosalmonae which causes proliferative kidney disease (pkd) of salmonid fish. because spores that develop in bryozoan colonies are infectious to fish, bryozoans represent the ultimate source of pkd. bryozoans produce numerous seed-like dormant stages called statoblasts that enable persistence during unfavourable conditions and achieve long-distance dispersal. the possibility th ... | 2014 | 24229733 |
| fate of tetracapsuloides bryosalmonae (myxozoa) after infection of brown trout salmo trutta and rainbow trout oncorhynchus mykiss. | tetracapsuloides bryosalmonae (myxozoa) is the causative agent of proliferative kidney disease in salmonids. we assessed differences in intensity of t. bryosalmonae infection between brown trout salmo trutta and rainbow trout oncorhynchus mykiss from the clinical phase of infection onwards. specific pathogen-free fish were exposed to t. bryosalmonae spores under controlled laboratory conditions and sampled at 6, 8, 10, 12, 14, and 17 wk post exposure (wpe), and the transmission of t. bryosalmona ... | 2013 | 24270019 |
| persistence of tetracapsuloides bryosalmonae (myxozoa) in chronically infected brown trout salmo trutta. | proliferative kidney disease (pkd) is a widespread disease of farmed and wild salmonid populations in europe and north america, caused by the myxozoan parasite tetracapsuloides bryosalmonae. limited studies have been performed on the epidemiological role in spread of the disease played by fish that survive infection with t. bryosalmonae. the aim of the present study was to evaluate the persistence of t. bryosalmonae developmental stages in chronically infected brown trout salmo trutta up to 2 yr ... | 2014 | 25144116 |
| differential modulation of host genes in the kidney of brown trout salmo trutta during sporogenesis of tetracapsuloides bryosalmonae (myxozoa). | tetracapsuloides bryosalmonae (myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids in europe and north america. in europe, spores of t. bryosalmonae develop in the kidney of infected brown trout salmo trutta and are released via urine to infect the freshwater bryozoan fredericella sultana. the transcriptomes of kidneys of infected and non-infected brown trout were compared by suppressive subtractive hybridization. differential screening and a subsequen ... | 2014 | 25297457 |
| first proliferative kidney disease outbreak in austria, linking to the aetiology of black trout syndrome threatening autochthonous trout populations. | proliferative kidney disease (pkd) was diagnosed in juvenile autochthonous brown trout salmo trutta for the first time in austria during summer 2014. cytology showed tetracapsuloides bryosalmonae sporoblasts, and histology revealed sporogonic (coelozoic) and extrasporogonic (histozoic) stages. analysis of malacosporean ribosomal small subunit revealed that this strain is closely related to european isolates, although its source is unknown. infection and high pathogenicity were reproduced upon a ... | 2016 | 27137070 |
| migrating zooids allow the dispersal of fredericella sultana (bryozoa) to escape from unfavourable conditions and further spreading of tetracapsuloides bryosalmonae. | fredericella sultana (bryozoa: phylactolaemata) is a primary host in the two-host life cycle of the myxozoan parasite tetracapsuloides bryosalmonae, the etiological agent of proliferative kidney disease (pkd) in salmonids. overtly infected f. sultana colonies were collected from river kamp (lower austria), following the first pkd outbreak affecting autochthonous brown trout (salmo trutta) in austria. zooids cultured under unfavourable conditions, e.g. hypertrophication or sudden temperature chan ... | 2016 | 27546864 |
| an epidemiological model for proliferative kidney disease in salmonid populations. | proliferative kidney disease (pkd) affects salmonid populations in european and north-american rivers. it is caused by the endoparasitic myxozoan tetracapsuloides bryosalmonae, which exploits freshwater bryozoans and salmonids as hosts. incidence and severity of pkd in brown trout populations have recently increased rapidly, causing a decline in fish catches and local extinctions in many river systems. pkd incidence and fish mortality are known to be enhanced by warmer water temperatures. theref ... | 2016 | 27596616 |
| conditional persistence and tolerance characterize endoparasite-colonial host interactions. | colonial hosts offer unique opportunities for exploitation by endoparasites resulting from extensive clonal propagation, but these interactions are poorly understood. the freshwater bryozoan, fredericella sultana, and the myxozoan, tetracapsuloides bryosalmonae, present an appropriate model system for examining such interactions. f. sultana propagates mainly asexually, through colony fragmentation and dormant propagules (statoblasts). our study examines how t. bryosalmonae exploits the multiple ... | 2017 | 28290261 |
| parasitism and phenotypic change in colonial hosts. | changes in host phenotype are often attributed to manipulation that enables parasites to complete trophic transmission cycles. we characterized changes in host phenotype in a colonial host–endoparasite system that lacks trophic transmission (the freshwater bryozoan fredericella sultana and myxozoan parasite tetracapsuloides bryosalmonae). we show that parasitism exerts opposing phenotypic effects at the colony and module levels. thus, overt infection (the development of infectious spores in the ... | 2013 | 23965820 |
| complex interaction between proliferative kidney disease, water temperature and concurrent nematode infection in brown trout. | proliferative kidney disease (pkd) is a temperature-dependent disease caused by the myxozoan tetracapsuloides bryosalmonae. it is an emerging threat to wild brown trout salmo trutta fario populations in switzerland. here we examined (1) how pkd prevalence and pathology in young-of-the-year (yoy) brown trout relate to water temperature, (2) whether wild brown trout can completely recover from t. bryosalmonae-induced renal lesions and eliminate t. bryosalmonae over the winter months, and (3) wheth ... | 2013 | 23670077 |
| characterisation of arginase paralogues in salmonids and their modulation by immune stimulation/ infection. | in this study we show that four arginase isoforms (arg1a, arg1b, arg2a, arg2b) exist in rainbow trout (oncorhynchus mykiss) and atlantic salmon (salmo salar). we have characterised these molecules in terms of a) sequence analysis, b) constitutive expression in different tissues, and modulated expression following c) stimulation of head kidney macrophages in vitro, or d) vaccination/infection with yersinia ruckeri and e) parasite infection (agd caused by paramoeba perurans and pkd caused by tetra ... | 2017 | 28025160 |
| establishment of medium for laboratory cultivation and maintenance of fredericella sultana for in vivo experiments with tetracapsuloides bryosalmonae (myxozoa). | the freshwater bryozoan fredericella sultana (blumenbach) is the most common invertebrate host of the myxozoan parasite tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease in salmonid fish. culture media play an important role in hatching of statoblasts and maintaining clean bryozoan colonies for malacosporea research. we developed a novel culture medium, bryozoan medium c (bmc), for the cultivation and maintenance of f. sultana under laboratory conditions. statobl ... | 2013 | 23121384 |
| castrating parasites and colonial hosts. | trajectories of life-history traits such as growth and reproduction generally level off with age and increasing size. however, colonial animals may exhibit indefinite, exponential growth via modular iteration thus providing a long-lived host source for parasite exploitation. in addition, modular iteration entails a lack of germ line sequestration. castration of such hosts by parasites may therefore be impermanent or precluded, unlike the general case for unitary animal hosts. despite these intri ... | 2012 | 22309795 |
| the effects of infection by tetracapsuloides bryosalmonae (myxozoa) and temperature on fredericella sultana (bryozoa). | the myxozoan, tetracapsuloides bryosalmonae, exploits freshwater bryozoans as definitive hosts, occurring as cryptic stages in bryozoan colonies during covert infections and as spore-forming sacs during overt infections. spores released from sacs are infective to salmonid fish, causing the devastating proliferative kidney disease (pkd). we undertook laboratory studies using mesocosm systems running at 10, 14 and 20 degrees c to determine how infection by t. bryosalmonae and water temperature inf ... | 2009 | 19504757 |
| sacculogenesis and sporogony of tetracapsuloides bryosalmonae (myxozoa: malacosporea) within the bryozoan host fredericella sultana (bryozoa: phylactolaemata). | tetracapsuloides bryosalmonae is the myxozoan parasite responsible for proliferative kidney disease (pkd) of salmonid fishes. this disease affects farmed species in north america and western europe where it results in significant economic losses for the rainbow trout industry. the parasite has two hosts in its life cycle, salmonid fish, and freshwater bryozoans. in this study, we describe the development of the parasite at the ultrastructural level within the bryozoan host fredericella sultana. ... | 2007 | 17205353 |
| proliferative, presaccular stages of tetracapsuloides bryosalmonae (myxozoa: malacosporea) within the invertebrate host fredericella sultana (bryozoa: phylactolaemata). | proliferative kidney disease (pkd), caused by the malacosporean parasite, tetracapsuloides bryosalmonae, is a major disease of salmonid culture both in western europe and north america. the fish are infected from spores that develop within freshwater bryozoans and are released into the water column. although sporogenesis has been studied in the bryozoan host and occurs within sacs, the formation of these sacs from presaccular stages has only been hypothesized. examination of infected bryozoans b ... | 2006 | 17152938 |
| temperature-driven proliferation of tetracapsuloides bryosalmonae in bryozoan hosts portends salmonid declines. | proliferative kidney disease (pkd) is an emerging disease of salmonid fishes. it is provoked by temperature and caused by infective spores of the myxozoan parasite tetracapsuloides bryosalmonae, which develops in freshwater bryozoans. we investigated the link between pkd and temperature by determining whether temperature influences the proliferation of t. bryosalmonae in the bryozoan host fredericella sultana. herein we show that increased temperatures drive the proliferation of t. bryosalmonae ... | 2006 | 16903234 |
| transmission of freshwater myxozoans during the asexual propagation of invertebrate hosts. | the phylum myxozoa contains over 1350 species almost all of which are considered to be obligate parasites of aquatic animals. the phylum is composed of two classes, the myxosporea and the malacosporea, species of which are important pathogens responsible for severe economic losses in cultured fisheries. the life cycles of freshwater myxozoa are believed to involve horizontal, indirect transmission, involving an invertebrate (oligochaetes or bryozoans) and a vertebrate host (fish or amphibians). ... | 2006 | 16373070 |
| infection of bryozoans by tetracapsuloides bryosalmonae at sites endemic for salmonid proliferative kidney disease. | laboratory-reared colonies of the bryozoans fredericella sultana and plumatella fungosa were placed upstream of 2 fish farms endemic for salmonid proliferative kidney disease (pkd) to assess rates of infection of bryozoans by tetracapsuloides bryosalmonae, the causative agent of pkd. colonies were deployed in the field for 8 trial periods of 2 wk each throughout the summer of 2001. following each trial, bryozoan colonies were maintained in laboratory culture for 28 d and were regularly monitored ... | 2003 | 14960034 |
| evidence that infectious stages of tetracapsula bryosalmonae for rainbow trout oncorhynchus mykiss are present throughout the year. | proliferative kidney disease (pkd) is a hyperplastic condition of the lymphoid tissue of salmonids infected with the spores of tetracapsula bryosalmonae, a myxozoan parasite formerly designated pkx, which has recently been described as a parasite of several species of bryozoans. the occurrence of pkd is generally associated with seasonal increase in water temperature, with research indicating that transmission of the disease does not occur below 12 to 13 degrees c. this suggested that the infect ... | 2001 | 11592700 |
| persistence, impacts and environmental drivers of covert infections in invertebrate hosts. | persistent covert infections of the myxozoan, tetracapsuloides bryosalmonae, in primary invertebrate hosts (the freshwater bryozoan, fredericella sultana) have been proposed to represent a reservoir for proliferative kidney disease in secondary fish hosts. however, we have limited understanding of how covert infections persist and vary in bryozoan populations over time and space and how they may impact these populations. in addition, previous studies have likely underestimated covert infection p ... | 2017 | 29096700 |
| integrated field, laboratory, and theoretical study of pkd spread in a swiss prealpine river. | proliferative kidney disease (pkd) is a major threat to wild and farmed salmonid populations because of its lethal effect at high water temperatures. its causative agent, the myxozoan tetracapsuloides bryosalmonae, has a complex lifecycle exploiting freshwater bryozoans as primary hosts and salmonids as secondary hosts. we carried out an integrated study of pkd in a prealpine swiss river (the wigger). during a 3-year period, data on fish abundance, disease prevalence, concentration of primary ho ... | 2017 | 29078391 |
| are brown trout salmo trutta fario and rainbow trout oncorhynchus mykiss two of a kind? a comparative study of salmonids to temperature-influenced tetracapsuloides bryosalmonae infection. | proliferative kidney disease (pkd) of salmonids caused by tetracapsuloides bryosalmonae causes high mortalities of wild brown trout (salmo trutta fario) and farmed rainbow trout (oncorhynchus mykiss) at elevated water temperatures. here the aim was to compare the temperature-dependent modulation of t. bryosalmonae in the two salmonid host species, which display different temperature optima. we used a novel experimental set-up in which we exposed brown trout and rainbow trout to an identical quan ... | 2018 | 28914447 |
| telomere length and antioxidant defense associate with parasite-induced retarded growth in wild brown trout. | early growth conditions can have profound impacts on individuals' development, growth and physiology, with subsequent long-term consequences for individuals' fitness and life expectancy. telomere length (tl) has been suggested to indicate both individual fitness and life expectancy in wide range of species, as the telomere attrition rate at early age can be accelerated due to exposure to various stressors, including parasites and inflammatory diseases, which increase production of reactive oxyge ... | 2017 | 28900791 |
| towards an in vitro culture method for the rainbow trout pathogen tetracapsuloides bryosalmonae. | | 2012 | 22924463 |
| temperature-related parasite infection dynamics: the case of proliferative kidney disease of brown trout. | climate change, in particular rising temperature, is suspected to be a major driver for the emergence of many wildlife diseases. proliferative kidney disease of salmonids, caused by the myxozoan tetracapsuloides bryosalmonae, was used to evaluate how temperature dependence of host-parasite interactions modulates disease emergence. brown trout (salmo trutta fario) kept at 12 and 15 °c, were experimentally infected with t. bryosalmonae. parasite development in the fish host and release of spores w ... | 2017 | 28831940 |
| first record of proliferative kidney disease agent tetracapsuloides bryosalmonae in wild brown trout and european grayling in finland. | the myxozoan endoparasite tetracapsuloides bryosalmonae causes temperature-driven proliferative kidney disease (pkd) in salmonid fishes. despite the economic and ecological importance of pkd, information about the distribution of the parasite is still scarce. here, we report for the first time the occurrence of t. bryosalmonae in wild brown trout salmo trutta and european grayling thymallus thymallus populations in finland. we detected t. bryosalmonae at high prevalence in both brown trout and e ... | 2017 | 28627494 |
| what goes around comes around: an investigation of resistance to proliferative kidney disease in rainbow trout oncorhynchus mykiss (walbaum) following experimental re-exposure. | rainbow trout oncorhynchus mykiss surviving proliferative kidney disease (pkd) are reported not to develop the disease upon re-exposure. however, the mechanisms involved in the immune response to re-exposure are unknown. we examined disease susceptibility and the immune response of naive 1+ rainbow trout when first exposed to tetracapsuloides bryosalmonae in comparison with that of 1+ rainbow trout re-exposed to t. bryosalmonae. pkd pathogenesis, parasite burden and transcriptional signatures of ... | 2017 | 28429822 |
| tetracapsuloides bryosalmonae abundance in river water. | tetracapsuloides bryosalmonae is a myxozoan parasite of freshwater bryozoans and salmonids, causing proliferative kidney disease in the latter. to date, detection of the parasite has required collection of hosts and subsequent molecular or histological examination. the release of infectious spores from both hosts offers an opportunity to detect the parasite in water samples. we developed a novel sybr® green quantitative real-time pcr (qpcr) assay for t. bryosalmonae in water samples which provid ... | 2017 | 28425427 |
| characterization of baff and april subfamily receptors in rainbow trout (oncorhynchus mykiss). potential role of the baff / april axis in the pathogenesis of proliferative kidney disease. | proliferative kidney disease (pkd) is a parasitic infection of salmonid fish characterized by hyper-secretion of immunoglobulins in response to the presence of the myxozoan parasite, tetracapsuloides bryosalmonae. in this context, we hypothesized that the baff/april axis, known to play a major role in b cell differentiation and survival in mammals, could be affected by the parasite and consequently be involved in the apparent shift in normal b cell activity. to regulate b cell activity, baff and ... | 2017 | 28323891 |
| comparative study of proliferative kidney disease in grayling thymallus thymallus and brown trout salmo trutta fario: an exposure experiment. | proliferative kidney disease (pkd) is an emerging disease threatening wild salmonid populations, with the myxozoan parasite tetracapsuloides bryosalmonae as the causative agent. species differences in parasite susceptibility and disease-induced mortality seem to exist. the aim of the present study was to compare incidence, pathology and mortality of pkd in grayling thymallus thymallus and brown trout salmo trutta under identical semi-natural conditions. young-of-the-year grayling and brown trout ... | 2017 | 28322206 |
| proliferative kidney disease in rainbow trout (oncorhynchus mykiss) under intensive breeding conditions: pathogenesis and haematological and immune parameters. | proliferative kidney disease (pkd) is an endoparasitic disease of salmonid fish caused by tetracapsuloides bryosalmonae (myxozoa: malacosporea). this study presents a comprehensive view on pkd development in rainbow trout (oncorhynchus mykiss) reared at an intensive fish breeding facility, with focus on mortality, pathology/histopathology, haematological findings and immune functions. diseased and reference fish were sampled monthly and time course of natural infection was followed up from the o ... | 2017 | 28291603 |
| who needs the hotspot? the effect of temperature on the fish host immune response to tetracapsuloides bryosalmonae the causative agent of proliferative kidney disease. | proliferative kidney disease (pkd) of salmonids, caused by tetracapsuloides bryosalmonae may lead to high mortalities at elevated water temperatures. however, it has not yet been investigated how temperature affects the fish host immune response to t. bryosalmonae. we exposed yoy (young of the year) rainbow trout (oncorhynchus mykiss) to t. bryosalmonae at two temperatures (12 °c and 15 °c) that reflect a realistic environmental scenario and could occur in the natural habitat of salmonids. we fo ... | 2017 | 28238860 |
| a survey of the distribution of the pkd-parasite tetracapsuloides bryosalmonae (cnidaria: myxozoa: malacosporea) in salmonids in norwegian rivers - additional information gleaned from formerly collected fish. | the malacosporean tetracapsuloides bryosalmonae was detected in kidneys from atlantic salmon parr in 64 of 91 sampled norwegian rivers. using real-time pcr, this parasite was found to be present in atlantic salmon parr in rivers along the whole coast, from the northernmost and southernmost areas of the country. in addition, t. bryosalmonae was found in kidneys from brown trout parr in 17 of 19 sampled rivers in south-east norway, and in arctic charr sampled in the river risfjordelva, located at ... | 2017 | 27523592 |
| proliferative kidney disease in brown trout: infection level, pathology and mortality under field conditions. | proliferative kidney disease (pkd) is an emerging disease threatening wild salmonid populations. in temperature-controlled aquaria, pkd can cause mortality rates of up to 85% in rainbow trout. so far, no data about pkd-related mortality in wild brown trout salmo trutta fario are available. the aim of this study was to investigate mortality rates and pathology in brown trout kept in a cage within a natural river habitat known to harbor tetracapsuloides bryosalmonae. young-of-the-year (yoy) brown ... | 2015 | 25993888 |
| tetracapsuloides bryosalmonae infection affects the expression of genes involved in cellular signal transduction and iron metabolism in the kidney of the brown trout salmo trutta. | tetracapsuloides bryosalmonae is an enigmatic endoparasite which causes proliferative kidney disease in various species of salmonids in europe and north america. the life cycle of the european strain of t. bryosalmonae generally completes in an invertebrate host freshwater bryozoan and vertebrate host brown trout (salmo trutta) linnaeus, 1758. little is known about the gene expression in the kidney of brown trout during the developmental stages of t. bryosalmonae. in the present study, quantitat ... | 2015 | 25786607 |
| induction of proliferative kidney disease (pkd) in rainbow trout oncorhynchus mykiss via the bryozoan fredericella sultana infected with tetracapsula bryosalmonae. | proliferative kidney disease (pkd) is a serious infection of wild and farmed salmonids, affecting mainly the kidney and spleen but becoming systemic in most susceptible fish hosts. this report deals with the transmission of tetracapsula bryosalmonae canning, curry, feist, longshaw & okamura 1999 from naturally infected bryozoans fredericella sultana blumenbach 1779 to naive rainbow trout oncorhynchus mykiss walbaum 1792, thereby confirming the recent conclusion based on partial 18s rdna sequence ... | 2001 | 11411645 |
| effect of environmental factors and an emerging parasitic disease on gut microbiome of wild salmonid fish. | the gastrointestinal tract (git) of fish supports a dynamic microbial ecosystem that is intimately linked to host nutrient acquisition, epithelial development, immune system priming, and disease prevention, and we are far from understanding the complex interactions among parasites, symbiotic gut bacteria, and host fitness. here, we analyzed the effects of environmental factors and parasitic burdens on the microbial composition and diversity within the git of the brown trout (salmo trutta). we fo ... | 2017 | 29276774 |
| a survey on tetracapsuloides bryosalmonae infections in slovene fresh waters. | slovenia has no history of health problems related to proliferative kidney disease (pkd) either in farmed or in wild fish. however, due to the past molecular evidence for the presence of tetracapsuloides bryosalmonae dna in tissues of some fish from open waters, a survey was conducted on wild salmonids that were primarily sampled for other purposes. in winter 2010-2011, specimens from a total of 244 rainbow trout, oncorhynchus mykiss (walbaum), and brown trout, salmo trutta l., from 30 bodies of ... | 2014 | 23941273 |
| immune gene expression profiling of proliferative kidney disease in rainbow trout oncorhynchus mykiss reveals a dominance of anti-inflammatory, antibody and t helper cell-like activities. | the myxozoan tetracapsuloides bryosalmonae is the causative agent of proliferative kidney disease (pkd) targeting primarily the kidney of infected fish where it causes a chronic lymphoid immunopathology. although known to be associated with suppression of some cellular aspects of innate immunity and a prominent lymphocytic hyperplasia, there remains a considerable knowledge gap in our understanding of the underlying immune mechanisms driving pkd pathogenesis. to provide further insights, the exp ... | 2013 | 23865616 |
| tetracapsuloides bryosalmonae and pkd in juvenile wild salmonids in denmark. | the myxozoan tetracapsuloides bryosalmonae is the causative agent of proliferative kidney disease (pkd), a widespread and serious condition in salmonid fishes in europe and north america. in europe, pkd is primarily reported affecting farmed rainbow trout oncorhynchus mykiss, but limited information exists on the occurrence and effects of t. bryosalmonae in wild salmonids. we investigated the presence of t. bryosalmonae in salmonids in denmark and found that the parasite is common in the dominan ... | 2012 | 23047189 |
| molecular crosstalk between a chemical and a biological stressor and consequences on disease manifestation in rainbow trout. | the aim of the present study was to examine the molecular and organism reaction of rainbow trout, oncorhynchus mykiss, to the combined impact of two environmental stressors. the two stressors were the myxozoan parasite, tetracapsuloides bryosalmonae, which is the etiological agent of proliferative kidney disease (pkd) and a natural stressor to salmonid populations, and 17β-estradiol (e2) as prototype of estrogen-active chemical stressors in the aquatic environment. both stressors, the parasite a ... | 2013 | 22440717 |
| a new class and order of myxozoans to accommodate parasites of bryozoans with ultrastructural observations on tetracapsula bryosalmonae (pkx organism). | tetracapsula bryosalmonae, formerly pkx organism, is a myxozoan parasite that causes proliferative kidney disease in salmonid fish. its primary hosts, in which it undergoes a sexual phase, are phylactolaemate bryozoans. it develops in the bryozoan coelomic cavity as freely floating sacs which contain two types of cells, stellate cells and sporoplasmogenic cells, which become organised as spores. eight stellate cells differentiate as four capsulogenic cells and four valve cells which surround a s ... | 2009 | 11001143 |
| kidney pathology and parasite intensity in rainbow trout oncorhynchus mykiss surviving proliferative kidney disease: time course and influence of temperature. | proliferative kidney disease (pkd) is an endoparasitic disease of salmonids caused by the myxozoan parasite tetracapsuloides bryosalmonae. we recently described the development of the disease from initial infection until manifestation of clinical disease signs in rainbow trout held at 2 water temperatures, 12 and 18°c. the aim of the present study is to investigate whether (1) infected fish surviving the clinical phase would recover from renal pathological changes, (2) whether they would be able ... | 2012 | 22422091 |
| tetracapsuloides bryosalmonae (myxozoa: malacosporea) portal of entry into the fish host. | the portal of entry and the penetration process of the myxozoan parasite tetracapsuloides bryosalmonae are still poorly understood. in the present study, spores of t. bryosalmonae derived from the bryozoan host (malacospores) were activated chemically and mechanically to investigate their reaction after attachment to the fish host in vitro. amoeboid movement of both sporoplasms was shown for the first time. the morphology of malacospores was assessed using scanning electron microscopy (sem). ope ... | 2010 | 20815328 |
| a novel minicollagen gene links cnidarians and myxozoans. | myxozoans are enigmatic endoparasitic organisms sharing morphological features with bilateria, protists and cnidarians. this, coupled with their highly divergent gene sequences, has greatly obscured their phylogenetic affinities. here we report the sequencing and characterization of a minicollagen homologue (designated tb-ncol-1) in the myxozoan tetracapsuloides bryosalmonae. minicollagens are phylum-specific genes encoding cnidarian nematocyst proteins. sequence analysis revealed a cysteine-ric ... | 2011 | 20810433 |
| tetracapsuloides bryosalmonae in spawning pink salmon, oncorhynchus gorbuscha (walbaum), in the quinsam river, british columbia, canada. | | 2010 | 20298450 |
| proliferative kidney disease (pkd) of rainbow trout: temperature- and time-related changes of tetracapsuloides bryosalmonae dna in the kidney. | proliferative kidney disease (pkd) of salmonids, caused by tetracapsuloides bryosalmonae, can lead to high mortalities at elevated water temperature. we evaluated the hypothesis that this mortality is caused by increasing parasite intensity. t. bryosalmonae-infected rainbow trout (oncorhynchus mykiss) were reared at different water temperatures and changes in parasite concentrations in the kidney were compared to cumulative mortalities. results of parasite quantification by a newly developed rea ... | 2009 | 19366483 |
| proliferative kidney disease in rainbow trout: time- and temperature-related renal pathology and parasite distribution. | proliferative kidney disease is a parasitic infection of salmonid fishes caused by tetracapsuloides bryosalmonae. the main target organ of the parasite in the fish is the kidney. to investigate the influence of water temperature on the disease in fish, rainbow trout oncorhynchus mykiss infected with t bryosalmonae were kept at 12 degrees c and 18 degrees c. the number of parasites, the type and degree of lesions in the kidney and the mortality rate was evaluated from infection until full develop ... | 2009 | 19301638 |
| site preference of myxozoans in the kidneys of hungarian fishes. | myxozoans are common parasites of fish kidneys, with most having specific sites of development. five specific sites of development include (1) the lumen of renal tubules, (2) the renal corpuscles followed by location in renal tubules, (3) intracellular location within the tubular epithelium followed by a stage in the lumen of the ducts, (4) haematopoietic tissue with dispersed trophozoites, and (5) haematopoietic tissue with large, localized plasmodia. a coelozoic development preceded by prespor ... | 2007 | 18159672 |
| immunostaining of spores and plasmodia of disparate myxozoan genera with comments on the properties of the sporular mucus envelope. | species of the phylum myxozoa are common parasites of fish and can cause severe losses in cultured species. although a number of myxozoan life-cycles have now been elucidated, little is known about the biology of these organisms in the fish host. monoclonal antibody b4 raised to the myxozoan tetracapsuloides bryosalmonae has been previously noted to react with a number of species infecting fish kidney. we present the results of a survey of 55 myxosporean species that determined that this antibod ... | 2006 | 16454867 |
| severe, chronic proliferative kidney disease (pkd) induced in rainbow trout oncorhynchus mykiss held at a constant 18 degrees c. | proliferative kidney disease (pkd), caused by the myxozoan parasite tetracapsuloides bryosalmonae, is well documented as a seasonal disease of rainbow trout oncorhynchus mykiss. water temperatures influence the course of the infection both within the fish and the invertebrate host, the recovery of fish from the disease being accelerated with decreasing water temperatures. during this study, groups of rainbow trout were held at a constant temperature (18 degrees c) for a sustained period of time ... | 2005 | 16261937 |
| first microsatellite loci of the myxozoan parasite tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (pkd). | proliferative kidney disease (pkd) caused by the myxozoan parasite tetracapsuloides bryosalmonae is a severe parasitic disease of salmonid fish. estimates of genetic variation in parasite populations across europe are currently lacking. we developed the first polymorphic microsatellite markers for t. bryosalmonae using illumina miseq sequence data derived from genomic dna. twelve polymorphic loci were identified from 24 tested loci. allelic variation was low at most loci, ranging from 2 to 6 (av ... | 2015 | 25667341 |
| interaction of tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease, with host proteins in the kidney of salmo trutta. | tetracapsuloides bryosalmonae (myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids which are found in europe and north america. less information about the interactions of t. bryosalmonae proteins with salmonid proteins during parasite development is known. in this study, anti-t. bryosalmonae monoclonal antibody-linked to n-hydroxysuccinimide-activated spin columns were used to purify parasite and host proteins from the kidneys of infected and non-infec ... | 2015 | 25663070 |
| identification of differentially expressed genes of brown trout (salmo trutta) and rainbow trout (oncorhynchus mykiss) in response to tetracapsuloides bryosalmonae (myxozoa). | tetracapsuloides bryosalmonae canning et al., 1999 (myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids in europe and north america. we have shown previously that the development and distribution of the european strain of t. bryosalmonae differs in the kidney of brown trout (salmo trutta) linnaeus, 1758 and rainbow trout (oncorhynchus mykiss) walbaum, 1792, and that intra-luminal sporogonic stages were found in brown trout but not in rainbow trout. we ... | 2015 | 25563603 |
| diversity and evolution of myxozoan minicollagens and nematogalectins. | myxozoa are a diverse group of metazoan parasites with a very simple organization, which has for decades eluded their evolutionary origin. their most prominent and characteristic feature is the polar capsule: a complex intracellular structure of the myxozoan spore, which plays a role in host infection. striking morphological similarities have been found between myxozoan polar capsules and nematocysts, the stinging structures of cnidarians (corals, sea anemones and jellyfish) leading to the sugge ... | 2014 | 25262812 |
| proliferative kidney disease (pkd) agent tetracapsuloides bryosalmonae in brown trout populations in estonia. | proliferative kidney disease (pkd) caused by the myxozoan parasite tetracapsuloides bryosalmonae is a serious parasitic disease threatening both farmed and wild salmonid populations, but very little is currently known about the distribution of the parasite in the baltic sea region. in this study we (1) report the development of a novel multiplex pcr method for fast and reliable screening of t. bryosalmonae; (2) use this multiplex pcr method to show that the pkd agent t. bryosalmonae is widesprea ... | 2014 | 24991741 |
| diversification and repeated morphological transitions in endoparasitic cnidarians (myxozoa: malacosporea). | malacosporeans are a poorly known myxozoan clade that uniquely demonstrates a tissue level of organisation. thus, when exploiting their invertebrate hosts (freshwater bryozoans) they occur as non-motile sacs or vermiform stages capable of active swimming. we combine phylogenetic analyses of ssu and lsu rdna with morphological observations to substantially enhance understanding of malacosporean diversification. the phylogenetic analyses incorporate the widest taxon sampling and geographic cover t ... | 2014 | 24675700 |
| [coincidental appearance of pkd and sphaerospora sp. (myxosporidia) in stock of salmo gairdneri (osteichthyes)]. | for the first time in europe simultaneous occurrence of pkx and sphaerospora sp. is recorded in salmo gairdneri. myxosporidian (?) forms hitherto not described have been observed in the kidney interstitium and the epithelium of the renal tubules, sporadically also in the swimbladder wall and the intestinal wall, besides the typical pkx organism in the kidney interstitium. sporogonic stages and spores of a sphaerospora species have been found in the lumen of the renal tubules. neither the exact i ... | 1988 | 3202329 |
| 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 |
| malacosporean-like spores in urine of rainbow trout react with antibody and dna probes to tetracapsuloides bryosalmonae. | tetracapsuloides bryosalmonae is the myxozoan parasite causing proliferative kidney disease (pkd) of salmonid fishes in europe and north america. the complete life cycle of the parasite remains unknown despite recent discoveries that the stages infectious for fish develop in freshwater bryozoans. during the course of examinations of the urine of rainbow trout (oncorhynchus mykiss) with or recovering from pkd we identified spores with features similar to those of t. bryosalmonae found in the bryo ... | 2004 | 14610667 |
| [pkd: the proliferative kidney disease in fish]. | the present study gives an overview about the knowledge and the diagnostic possibilities of the proliferative kidney disease (pkd) in fishes. this disease is responsible for economically significant losses in farmed fish and severe reductions in wild fish populations in europe and north america. pkd is affecting mainly salmonid species. in swiss rivers the proliferative kidney disease pictures the highest percentage of diseases among brown trouts. the main symptom of pkd is a massive proliferati ... | 2003 | 14593933 |
| development and release of a malacosporean (myxozoa) from plumatella repens (bryozoa: phylactolaemata). | during an experiment to transmit tetracapsula bryosalmonae canning, curry, feist, longshaw et okamura, 1999 to a laboratory-cultured bryozoan, plumatella repens l. a previously undescribed malacosporean species was noted. this parasite produced sacs of spores in the host that reached 1.2 mm in length. the spores released from the sacs appeared similar in size to the two species of tetracapsula previously described although slight differences in form were noted. release of spores from the bryozoa ... | 2002 | 11993548 |
| rapid diagnosis of tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (pkd) in salmonid fish by a novel dna amplification method, loop-mediated isothermal amplification (lamp). | a new molecular diagnostic assay was developed for detection of tetracapsuloides bryosalmonae the causative agent of proliferative kidney disease (pkd) in salmonid fish using a loop-mediated isothermal amplification method (lamp). the pkd-lamp assay amplifies the t. bryosalmonae dna extracted from infected kidney, under constant temperature of 65 degrees c within 1 h. the required equipment for dna amplification is only a water bath. the amplification products were detected visually by using syb ... | 2005 | 15895254 |
| the phylogeography of salmonid proliferative kidney disease in europe and north america. | salmonid proliferative kidney disease (pkd) is caused by the myxozoan tetracapsuloides bryosalmonae. given the serious and apparently growing impact of pkd on farmed and wild salmonids, we undertook a phylogeographic study to gain insights into the history of genealogical lineages of t. bryosalmonae in europe and north america, and to determine if the global expansion of rainbow trout farming has spread the disease. phylogenetic analyses of internal transcribed spacer 1 sequences revealed a clad ... | 2004 | 15306294 |
| localization of carbohydrate terminals on tetracapsuloides bryosalmonae using lectin histochemistry and immunogold electron microscopy. | tetracapsuloides bryosalmonae is the myxozoan parasite that causes the commercially important proliferative kidney disease (pkd) in salmonid aquaculture. previous studies on the binding of lectins to t. bryosalmonae identified griffonia simplificola agglutinin i (gs i) as useful for parasite identification. this lectin was also implicated as recognizing antigenic structures on the parasite. here, we examine the histochemical staining and ultrastructural localization of a panel of 21 lectins on t ... | 2004 | 14986938 |
| the expression of immune-regulatory genes in rainbow trout, oncorhynchus mykiss, during a natural outbreak of proliferative kidney disease (pkd). | proliferative kidney disease (pkd) is a parasitic infection of salmonid fish characterized by an apparently abnormal immune response to the presence of the myxozoan parasite, tetracapsuloides bryosalmonae. in order to examine the nature of the immune response at the molecular level, the expression of a range of immune regulatory genes, including cytokines and cyclooxygenase (cox)-2 was examined in naive unexposed fish and in naive fish exposed to parasite-infected water at three points during th ... | 2003 | 14667176 |