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development of a diagnostic pcr to detect neoparamoeba perurans, agent of amoebic gill disease.the recent description of neoparamoeba perurans as an aetiological agent of amoebic gill disease (agd) advanced our understanding of the condition and has forced a re-evaluation of methods used for the diagnosis of agd. currently, there are no tools available that are both specific for n. perurans and suitable for a routine diagnostic procedure. therefore, in this study we describe an assay to detect n. perurans. the assay, which utilizes pcr to amplify the n. perurans 18s rrna gene, was shown t ...200818353020
impact and control of protozoan parasites in maricultured fishes.aquaculture, including both freshwater and marine production, has on a world scale exhibited one of the highest growth rates within animal protein production during recent decades and is expected to expand further at the same rate within the next 10 years. control of diseases is one of the most prominent challenges if this production goal is to be reached. apart from viral, bacterial, fungal and metazoan infections it has been documented that protozoan parasites affect health and welfare and the ...201523448656
administration of recombinant attachment protein (r22c03) of neoparamoeba perurans induces humoral immune response against the parasite in atlantic salmon (salmo salar).this study investigated the use of a recombinant protein of neoparamoeba perurans, the causative agent of amoebic gill disease (agd), as an immunogen to generate systemic and mucosal antibody responses against the parasite. genes encoding n. perurans homologs of mannose-binding protein (mbp) from acanthamoeba spp. have been identified. from these, a neoparamoeba mbp - like est has been identified and produced as a recombinant fusion protein. attachment of n. perurans to the gill might be reduced ...201424721287
differentially expressed proteins in gill and skin mucus of atlantic salmon (salmo salar) affected by amoebic gill disease.the external surfaces of fish, such as gill and skin, are covered by mucus, which forms a thin interface between the organism and water. amoebic gill disease (agd) is a parasitic condition caused by neoparamoeba perurans that affects salmonids worldwide. this disease induces excessive mucus production in the gills. the host immune response to agd is not fully understood, and research tools such as genomics and proteomics could be useful in providing further insight. gill and skin mucus samples w ...201424979223
effects of single and repeated infections with neoparamoeba perurans on antibody levels and immune gene expression in atlantic salmon (salmo salar).amoebic gill disease (agd) is the main health problem for the salmon industry in tasmania, australia and is now reported in most salmon producing countries. antibody and gene expression responses to the pathogen, neoparamoeba perurans, have been studied independently following primary exposure; however, the effects of sequential reinfection, which can often occur during net-pen culture of salmon, remain unclear. the association between the transcription of immunoglobulin (ig) and their systemic ...201525433137
immunity to amoeba.amoebic infections in fish are most likely underestimated and sometimes overlooked due to the challenges associated with their diagnosis. amoebic diseases reported in fish affect either gills or internal organs or may be systemic. host response ranges from hyperplastic response in gill infections to inflammation (including granuloma formation) in internal organs. this review focuses on the immune response of atlantic salmon to neoparamoeba perurans, the causative agent of amoebic gill disease (a ...201423921258
first record of amoebic gill disease caused by neoparamoeba perurans in south africa. 201423763465
changes in the interbranchial lymphoid tissue of atlantic salmon (salmo salar) affected by amoebic gill disease.the interbranchial lymphoid tissue (ilt) was recently described in the gills of salmonids. this study examined changes in the ilt during a parasitic infection in marine environment, using amoebic gill disease (agd) as a model. atlantic salmon (salmo salar) experimentally infected with neoparamoeba perurans were sampled at 0, 3, 7, 14 and 28 days post challenge. transversal sections of three areas of the gills (dorsal, medial and ventral) were histologically assessed for morphological and cellula ...201425451002
vaccination with recombinant protein (r22c03), a putative attachment factor of neoparamoeba perurans, against agd in atlantic salmon (salmo salar) and implications of a co-infection with yersinia ruckeri.amoebic gill disease (agd) affects salmonids during the marine grow-out phase in the tasmanian industry and in other major salmonid producing countries. during the period post-transfer to seawater, the bacterial condition yersiniosis can also cause high levels of mortality in atlantic salmon grown in tasmania, in addition to the hatchery outbreaks. the recombinant protein r22c03, a mannose-binding protein-like (mbp-like) similar to attachment factors of other amoebae, was tested as a vaccine can ...201525804487
neoparamoeba perurans loses virulence during clonal culture.amoebic gill disease affects farmed salmonids and is caused by neoparamoeba perurans. clonal cultures of this amoeba have been used for challenge experiments, however the effect of long-term culture on virulence has not been investigated. here we show, using in vitro and in vivo methods, that a clone of n. perurans which was virulent 70 days after clonal culture lost virulence after 3 years in clonal culture. we propose that this is related either to the lack of attachment to the gills or the ab ...201526008963
in vitro cultured neoparamoeba perurans causes amoebic gill disease in atlantic salmon and fulfils koch's postulates.amoebic gill disease (agd) in marine farmed atlantic salmon is of growing concern worldwide and remains a significant health issue for salmon growers in australia. until now the aetiological agent, neoparamoeba perurans, has not been amenable to in vitro culture and therefore koch's postulates could not be fulfilled. the inability to culture the amoeba has been a limiting factor in the progression of research into agd and required the maintenance of an on-going laboratory-based infection to supp ...201222549025
which th pathway is involved during late stage amoebic gill disease?amoebic gill disease (agd) is an emerging disease in north european atlantic salmon (salmo salar linnaeus 1758) aquaculture caused by the amoeba paramoeba perurans. the host immune response to agd infection is still not well understood despite past attempts to investigate host-pathogen interactions. with the significant increase in our knowledge of cytokine genes potentially involved in th responses in recent years, we examined their involvement in this disease using atlantic salmon post-smolts ...201526166456
involvement of contractile vacuoles in the osmoregulation process of the marine parasitic amoeba neoparamoeba perurans. 201626332530
morphological diversity of paramoeba perurans trophozoites and their interaction with atlantic salmon, salmo salar l., gills.amoebic gill disease (agd) caused by the ectoparasite paramoeba perurans affects several cultured marine fish species worldwide. in this study, the morphology and ultrastructure of p. perurans in vitro and in vivo was investigated using scanning and transmission electron microscopy (sem and tem, respectively). amoebae cultures contained several different morphologies ranging from a distinct rounded cell structure and polymorphic cells with pseudopodia of different lengths and shapes. sem studies ...201626775899
hydrogen peroxide treatment in atlantic salmon induces stress and detoxification response in a daily manner.daily variation in the absorption, metabolism and excretion of toxic substances will ultimately determine the actual concentration to which the cells and tissues are exposed. in aquaculture, atlantic salmon (salmo salar) can be frequently exposed to hydrogen peroxide (h2o2) to treat topical skin and gill infections, particularly in relation to parasitic infections (e.g. sea lice lepeophtheirus salmonis and amoebic gill disease caused by neoparamoeba perurans). it is well accepted that the time o ...201627058450
generation of paramoeba perurans clonal cultures using flow cytometry and confirmation of virulence.amoebic gill disease (agd) in farmed atlantic salmon is caused by the amoeba paramoeba perurans. the recent establishment of in vitro culture techniques for p. perurans has provided a valuable tool for studying the parasite in detail. in this study, flow cytometry was used to generate clonal cultures from single-sorted amoeba, and these were used to successfully establish agd in experimental atlantic salmon. the clonal cultures displayed differences in virulence, based on gill scores. the p. per ...201727524425
pcr survey for paramoeba perurans in fauna, environmental samples and fish associated with marine farming sites for atlantic salmon (salmo salar l.).amoebic gill disease (agd) caused by the amoeba paramoeba perurans is an increasing problem in atlantic salmon aquaculture. in the present pcr survey, the focus was to identify reservoir species or environmental samples where p. perurans could be present throughout the year, regardless of the infection status in farmed atlantic salmon. a total of 1200 samples were collected at or in the proximity to farming sites with agd, or with history of agd, and analysed for the presence of p. perurans. no ...201627594383
amoebic gill infection in coho salmon oncorhynchus kisutch farmed in korea.about 70% mortality occurred in cultured coho salmon oncorhynchus kisutch at a marine farm in the south sea of korea in 2014. diseased fish showed greyish or pale patches on the gills, with no internal signs of disease. no bacteria or viruses were isolated from diseased fish, but numerous amoebae were found on the gills. histopathological examinations revealed extensive hyperplastic epithelium and lamellar fusion in the gills. numerous amoebae were seen between gill filaments. the amoebae had a ...201627596862
pseudocyst formation in the marine parasitic amoeba neoparamoeba perurans: a short-term survival strategy to abrupt salinity variation. 201628000922
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 ...201728025160
a review of infectious gill disease in marine salmonid fish.infectious gill diseases of marine salmonid fish present a significant challenge in salmon-farming regions. infectious syndromes or disease conditions affecting marine-farmed salmonids include amoebic gill disease (agd), proliferative gill inflammation (pgi) and tenacibaculosis. pathogens involved include parasites, such as neoparamoeba perurans, bacteria, such as piscichlamydia salmonis and tenacibaculum maritimum, and viruses, such as the atlantic salmon paramyxovirus (aspv). the present level ...201121401646
amoebic gill disease resistance is not related to the systemic antibody response of atlantic salmon, salmo salar l.amoebic gill disease (agd) is a proliferative gill tissue response caused by neoparamoeba perurans and is the main disease affecting australian marine farmed atlantic salmon. we have previously proposed that macroscopic gill health ('gill score') trajectories and challenge survival provide evidence of a change in the nature of resistance to agd. in order to examine whether the apparent development of resistance was because of an adaptive response, serum was sequentially sampled from the same ind ...201019943840
first cases of amoebic gill disease (agd) in norwegian seawater farmed atlantic salmon, salmo salar l., and phylogeny of the causative amoeba using 18s cdna sequences.amoebic gill disease (agd) was observed in seawater farmed atlantic salmon at four geographically distant locations on the western coast of norway. to the best of our knowledge, these are the first detected agd outbreaks in norway. the outbreaks lasted for 7-12 weeks in late autumn 2006 and were for the most part concurrent. the crude, cumulative mortality was in the range of 12-20% at three farms and 82% at a fourth. the histopathology showed uniform parasomal amoebae in lesions characteristic ...200818261034
neoparamoeba perurans n. sp., an agent of amoebic gill disease of atlantic salmon (salmo salar).amoebic gill disease (agd) is a potentially fatal disease of some marine fish. two amphizoic amoebae neoparamoeba pemaquidensis and neoparamoeba branchiphila have been cultured from agd-affected fish, yet it is not known if one or both are aetiological agents. here, we pcr amplified the 18s rrna gene of non-cultured, gill-derived (ncgd) amoebae from agd-affected atlantic salmon (salmo salar) using n. pemaquidensis and n. branchiphila-specific oligonucleotides. variability in pcr amplification le ...200717561022
development of an in vitro model system for studying bacterially expressed dsrna-mediated knockdown in neoparamoeba genus.rna interference (rnai) has been extensively used to study gene function in non-model organisms and has the potential to identify parasite target molecules in order to develop alternative treatment strategies. this technology could assist in further development of preventive methods against amoebic gill disease (agd), the main health problem affecting the atlantic salmon aquaculture industry in tasmania (australia) and now a significant emerging issue in europe. using β-actin and ef1-α as candid ...201424510372
evidence of immune and inflammatory processes in the gills of agd-affected atlantic salmon, salmo salar l.amoebic gill disease (agd) is a disease caused by the ectoparasite neoparamoeba perurans which affects several cultured marine fish worldwide. the characterisation of pro-inflammatory and immune related genes at the mrna level in agd-affected atlantic salmon gills was performed at 10 days post-inoculation using 2d quantitative rt-pcr, a method of mapping transcriptional responses in tissues. the genes of interest were il-1β, tnf-α, tcr-α chain, cd8, cd4, mhc-iiα, mhc-i, igm and igt. a significan ...201424378682
evaluation of fixation methods for demonstration of neoparamoeba perurans infection in atlantic salmon, salmo salar l., gills.formaldehyde-based fixatives are generally employed in histopathology despite some significant disadvantages associated with their usage. formaldehyde fixes tissue by covalently cross-linking proteins, a process known to mask epitopes which in turn can reduce the intensity of immunohistochemical stains widely used in disease diagnostics. additionally, formaldehyde fixation greatly limits the ability to recover dna and mrna from fixed specimens to the detriment of further downstream molecular ana ...201323384040
preliminary success using hydrogen peroxide to treat atlantic salmon, salmo salar l., affected with experimentally induced amoebic gill disease (agd).currently, the only effective and commercially used treatment for amoebic gill disease (agd) in farmed tasmanian atlantic salmon is freshwater bathing. hydrogen peroxide (h₂o₂), commonly used throughout the aquaculture industry for a range of topical skin and gill infections, was trialled in vitro and in vivo to ascertain its potential as an alternative treatment against agd. under in vitro conditions, trophozoites of neoparamoeba perurans were exposed to three concentrations of h₂o₂ in sea wate ...201222882640
detection of neoparamoeba perurans by duplex quantitative taqman real-time pcr in formalin-fixed, paraffin-embedded atlantic salmonid gill tissues.the development and the application of a quantitative duplex real-time pcr for the detection of neoparamoeba perurans and the elongation factor α 1 gene (elf) of atlantic salmon, salmo salar l., and rainbow trout, oncorhynchus mykiss (walbaum), are described. a set of primers and probe was designed to amplify a 139-bp fragment specific to the n. perurans 18s rrna gene. the test was shown to be very sensitive, being able to detect as little as 13.4 dna copies per μl corresponding to 0.15 fg of te ...201222804799
amoebic gill disease outbreak in marine fish cultured in korea.in 2015, 6.7-60% mortality was observed in black seabream ( acanthopagrus schlegelii), rock bream ( oplegnathus fasciatus), and gray mullet ( mugil cephalus) farmed in the southern coast of korea. on examination, numerous amoebae were found on the gills of these 3 fish species with detection rate of 100%. some rock bream and gray mullet were coinfected with bacteria ( pseudomonas anguilliseptica, vibrio tapetis, or vibrio anguillarum). histologic examination revealed extensive hyperplastic epith ...201728205457
detection of a parasitic amoeba (order dactylopodida) in the female gonads of oysters in brazil.the impacts of oocyte parasites on the reproductive success of molluscs are largely unknown. in this study, we evaluated the presence of gonad parasites in 6 species of marine bivalve molluscs native to southern brazil. cultured bivalves included the mangrove oyster crassostrea gasar (sometimes called c. brasiliana), the brown mussel perna perna, the lion's paw scallop nodipecten nodosus and the wing pearl oyster pteria hirundo. another species of mangrove oyster, c. rhizophorae, and the carib p ...201424991850
cloning and functional characterisation of a peroxiredoxin 1 (nkef a) cdna from atlantic salmon (salmo salar) and its expression in fish infected with neoparamoeba perurans.peroxiredoxin 1 (prx 1), also known as natural killer enhancing factor a (nkef a), has been implicated in the immune response of both mammals and fish. amoebic gill disease (agd), caused by neoparamoeba perurans, is a significant problem for the atlantic salmon (salmo salar l.) aquaculture industry based in tasmania, australia. here we have cloned and functionally characterized a prx 1 open reading frame (orf) from atlantic salmon liver and shown that prx 1 gene expression was down-regulated in ...201222450240
do salmon lice, lepeophtheirus salmonis, have a role in the epidemiology of amoebic gill disease caused by neoparamoeba perurans? 201020412358
amoebic gill disease in hatchery-reared ayu, plecoglossus altivelis (temminck & schlegel), in japan is caused by neoparamoeba perurans. 201020158576
neoparamoeba perurans is a cosmopolitan aetiological agent of amoebic gill disease.previously we described a new member of the neoparamoeba genus, n. perurans, and showed that it is an agent of amoebic gill disease (agd) of atlantic salmon salmo salar cultured in southeast tasmania, australia. given the broad distribution of cases of agd, we were interested in extending our studies to epizootics in farmed fish from other sites around the world. oligonucleotide probes that hybridise with the 18s rrna of n. perurans, n. branchiphila or n. pemaquidensis were used to examine archi ...200818380220
description of an atlantic salmon (salmo salar l.) type ii interleukin-1 receptor cdna and analysis of interleukin-1 receptor expression in amoebic gill disease-affected fish.previously, we showed that il-1β transcription is induced in the gills of amoebic gill disease (agd)-affected fish in an agd lesion-restricted fashion. however, in this environment, there is very little evidence of inflammation on histopathological or transcriptional levels and we hypothesised that aberrant signalling may occur. as a first step in investigating this issue, we cloned and sequenced the atlantic salmon il-1 receptor type ii (il-1rii) mrna, and then examined the expression of both t ...201222433573
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