Journal of Fish Diseases via MedWorm.com

The response of intestinal mucous cells to the presence of enteric helminths: their distribution, histochemistry and fine structure

Journal of Fish Diseases — Tue, 09 Mar 2010 00:00:00 +0100

Histochemical and ultrastructural investigations were conducted on the mucous cells of the intestine of brown trout, Salmo trutta L., naturally infected with the cestode Cyathocephalus truncatus (Pallas, 1781) and the acanthocephalan Echinorhynchus truttae Shrank, 1788. A subpopulation of 45 S. trutta were examined of which 15 specimens harboured E. truttae, 15 of which were infected with C. truncatus and 15 fish, the control group, were uninfected. In histological sections, hyperplasia and hypertrophy of the mucous cells were evident at the site of parasite infection. Enhanced mucus secretion was also recorded in infected fish. The number of mucous cells close to the site of parasite attachment within the intestine was significantly higher than the number detected in uninfected individual...

Evaluation of histopathology, real-time PCR and virus isolation for diagnosis of infectious salmon anaemia in Norwegian salmon using latent class analysis

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

Changes in skin mucus of common carp, Cyprinus carpio L., after exposure to water with a high bacterial load

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

In this study, the effect of an increase of overall bacterial load in tank water on carp skin mucus was assessed. Intracellular and released high molecular weight glycoproteins (HMGs) of carp skin mucus were analysed for changes using histological, histochemical and biochemical techniques. Increase of bacterial load did not induce obvious clinical responses in carp, but the skin of exposed carp responded quickly. The amount of skin mucus HMGs isolated increased as well as their total glycosylation. An increased goblet cell number was observed for all carbohydrate stainings, but most clearly for acidic glycoconjugates. A change in the terminal presence of some sugars was also seen. After the initial response of carp, an adaptation to the higher bacterial load in the water appeared to occur ...

First description of atypical furunculosis in freshwater farmed Atlantic salmon, Salmo salar L., in Chile

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

We report the first isolation, identification and characterization of a group of Chilean strains of atypical Aeromonas salmonicida isolated from freshwater farmed Atlantic salmon, Salmo salar. Affected fish showed superficial ulcers and pale liver with or without petechial haemorrhages. Outbreaks of the disease occurred in two farms in the south of Chile about 2200 km apart. Five strains were isolated in pure culture and identified by serological assays and immunofluorescence tests as belonging to Aeromonas salmonicida. Although the bacterial isolates were phenotypically homogeneous, minor differences with the reference strain A. salmonicida subsp. salmonicida ATCC 33658 were noted. Three specific primer sets and partial 16S rRNA gene sequencing allowed the identification of the Chilean is...

Treatment development for systemic Tetrahymena sp. infection in guppies, Poecilia reticulata Peters

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

Antibacterial and antiparasitic agents and a cysteine protease inhibitor (E-64) were tested against Tetrahymena infection, a serious problem in guppy production worldwide. Chemicals were tested in vitro by a colorimetric assay for Tetrahymena survival. The most effective were niclosamide, albendazole and chloroquine, with 23%, 35% and 60% survival, respectively, following 2-h exposure to 100 ppm. Longer incubation periods resulted in greater reductions in survival. Niclosamide was further studied in vivo at different dosages, administered orally to Tetrahymena-infected guppies. Mortality rates were significantly lower in all treatment groups; in trial I, 30% and 33% mortality in 5 and 40 mg kg[minus]1 niclosamide-fed fish vs. 59% mortality in controls; in trial II, 35%, 13% and 10% in 50, ...

Clinical white spot disease status in Penaeus monodon during the middle of the culture period – its epidemiological significance

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

Tetracapsuloides bryosalmonae in spawning pink salmon, Oncorhynchus gorbuscha (Walbaum), in the Quinsam River, British Columbia, Canada

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

White spot syndrome virus in wild penaeid shrimp caught in coastal and offshore waters in the southern Atlantic Ocean

Journal of Fish Diseases — Fri, 05 Mar 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

Protection against heterologous Streptococcus iniae isolates using a modified bacterin vaccine in Nile tilapia, Oreochromis niloticus (L.)

Journal of Fish Diseases — Fri, 05 Mar 2010 00:00:00 +0100

The objectives of this study were to determine whether a developed modified S. iniae (ARS-98-60) bacterin vaccine is efficacious in Nile tilapia, Oreochromis niloticus (L.), against challenge with heterologous isolates from diverse geographical locations and to evaluate protein and antigenic variability among the isolates tested. Two groups of tilapia (approximately 5 g) were intraperitoneally (IP) vaccinated with 100 [mu]L of the vaccine or sham vaccinated with 100 [mu]L of sterile tryptic soy broth and held for 28 days. Fish were challenged with each isolate by IP injection of 2[ndash]3 × 107 CFU per fish using calcein to mark fish prior to cohabitation for challenge. The results demonstrated significant protection against all challenge isolates, and relative percent survivals ranged fr...

A comparative epizootiologic study of the two fish-pathogenic serovars of Vibrio vulnificus biotype 2

Journal of Fish Diseases — Fri, 12 Feb 2010 00:00:00 +0100

In conclusion, serovar A seems to represent a new antigenic form of V. vulnificus biotype 2 with an unusual portal of entry and is better adapted to fresh water than serovar E. (Source: Journal of Fish Diseases)

Viral haemorrhagic septicaemia virus IVb inactivation by ultraviolet light, and storage viability at 4 and −20 °C

Journal of Fish Diseases — Fri, 12 Feb 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

Molecular detection of betanodavirus from the farmed fish, Platax orbicularis (Forsskal) (Ephippidae), in French Polynesia

Journal of Fish Diseases — Fri, 12 Feb 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

Amoebic gill disease in hatchery-reared ayu, Plecoglossus altivelis (Temminck & Schlegel), in Japan is caused by Neoparamoeba perurans

Journal of Fish Diseases — Thu, 11 Feb 2010 00:00:00 +0100

(Source: Journal of Fish Diseases)

Viral haemorrhagic septicaemia virus IVb experimental infection of rainbow trout, Oncorhynchus mykiss (Walbaum), and fathead minnow, Pimphales promelas (Rafinesque)

Journal of Fish Diseases — Wed, 10 Feb 2010 00:00:00 +0100

Viral haemorrhagic septicaemia virus (VHSV) in the Great Lakes has had a dramatic impact on fish husbandry because of the implications of the presence of a reportable disease. Experimental infections with VHSV IVb were conducted in rainbow trout, Oncorhynchus mykiss (Walbaum), and fathead minnows, Pimphales promelas (Rafinesque), to examine their susceptibility and the clinical impact of infection. Triplicate groups of rainbow trout (n = 40) were injected intraperitoneally (i.p.) with 100 [mu]L 106.550% tissue culture infective doses (TCID50) or waterborne exposed to graded doses (104.5, 106.5, and 108.5 TCID50 mL[minus]1) of VHSV IVb. Duplicate groups of fathead minnows (n = 15) were i.p. injected with (106.5 TCID50 100 [mu]L) or waterborne exposed (106.5 TCID50 mL[minus]1). All experimen...

Dried leaves of Rosmarinus officinalis as a treatment for streptococcosis in tilapia

Journal of Fish Diseases — Wed, 10 Feb 2010 00:00:00 +0100

Dietary application of dried Rosmarinus officinalis (rosemary) leaves as a treatment for streptococcal infection was studied in tilapia, Oreochromis sp. Feeding with dried rosemary leaves significantly reduced mortality following infection with Streptococcus iniae: 44% mortality in the group fed 8% rosemary, similar to oxytetracycline treatment (43% mortality), and significantly lower than the control (65%). Dietary administration of 16% rosemary significantly reduced mortality because of Streptococcus agalactiae infection in 44 g fish (62% and 76% in 16% rosemary and control, respectively), but not in a similar experiment conducted with 5.5 g fish. The antibacterial effect of rosemary on S. iniae was studied. Activity of rosemary cultivar Israel was reduced during the winter, but there wa...

Salmonid alphavirus (SAV) and pancreas disease (PD) in Atlantic salmon, Salmo salar L., in freshwater and seawater sites in Norway from 2006 to 2008

Journal of Fish Diseases — Wed, 10 Feb 2010 00:00:00 +0100

A cohort study was initiated in the spring of 2006 to investigate epidemiological aspects and pathogenesis of salmonid alphavirus (SAV) subtype 3 infections and pancreas disease (PD). The aims were to assess involvement of the freshwater production phase, the extent and frequency of subclinical infections and to follow PD-affected populations throughout the entire seawater production cycle, as well as investigate possible risk factors for PD outbreaks. Fish groups from 46 different Atlantic salmon freshwater sites in six counties were sampled once prior to seawater transfer and followed onto their seawater sites. A total of 51 Atlantic salmon seawater sites were included, and fish groups were sampled three times during the seawater production phase. SAV subtype 3 was not identified by real...

Impact of yellow head virus outbreaks in the whiteleg shrimp, Penaeus vannamei (Boone), in Thailand

Journal of Fish Diseases — Wed, 10 Feb 2010 00:00:00 +0100

Yellow head virus (YHV) is known as a major pathogen in the black tiger shrimp, Penaeus (Penaeus) monodon. It can also cause serious mortality in farmed whiteleg shrimp, Penaeus (Litopenaeus) vannamei. However, there is no published information on the economic and/or production impact of the disease in P. vannamei. Shrimp with gross signs of YHV disease (faded body colour and 60[ndash]70% mortality) were observed in 20 study farms rearing P. vannamei in the central part of Thailand from the end of 2007 through early 2008. The estimated economic loss for these farms according to the Thai Animal Aquaculture Association was approximately US$3 million. Detailed sequence analysis of RT-PCR amplicons from shrimp in all the study ponds revealed the presence of YHV Type 1b (YHV-1b) alone (characte...

Use of lupin, Lupinus perennis, mango, Mangifera indica, and stinging nettle, Urtica dioica, as feed additives to prevent Aeromonas hydrophila infection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Mon, 25 Jan 2010 00:00:00 +0100

Feeding rainbow trout, Oncorhynchus mykiss (Walbaum), with 1% lupin, Lupinus perennis, mango, Mangifera indica, or stinging nettle, Urtica dioica, for 14 days led to reductions in mortality after challenge with Aeromonas hydrophila. In addition, there was significant enhancement in serum bactericidal activity, respiratory burst and lysozyme activity in the treatment groups compared to the controls. Use of lupin and mango led to the highest number of red blood and white blood cells in recipient fish, with use of stinging nettle leading to the highest haematocrit and haemoglobin values; the highest value of mean corpuscular volume and haemoglobin was in the control groups and those fed with stinging nettle. (Source: Journal of Fish Diseases)

Difference in genes between a high virulence strain G4 and a low virulence strain G18 of Flavobacterium columnare by using suppression subtractive hybridization

Journal of Fish Diseases — Sun, 24 Jan 2010 00:00:00 +0100

Flavobacterium columnare is the causative agent of columnaris disease. Different genetic groups of F. columnare show to some extent different degrees of virulence. To identify genetic differences between the high virulence strain G4 and the low virulence strain G18 of F. columnare, suppression subtractive hybridization was used. A total of 46 genes were identified from the virulent strain G4, 35 of which showed some degree of homology with known proteins and can be classified into 11 categories: DNA replication or recombination proteins, inorganic ion transport proteins, outer membrane proteins, enterotoxin, binding proteins, YD repeat proteins, transposase, chaperon, signal transduction-related proteins, regulatory proteins, metabolism-related proteins. Several putative virulence factors ...

Establishment and characterization of a fibroblast cell line derived from the dorsal fin of red sea bream, Pagrus major (Temminck & Schlegel)

Journal of Fish Diseases — Wed, 20 Jan 2010 00:00:00 +0100

The establishment and partial characterization of a continuous cell line from the dorsal fin of red sea bream, Pagrus major, are described. The cell line, designated RSBF-2, has been subcultured for more than 100 passages since its initiation in November 2000. It was optimally maintained at 28 °C in Leibovitz L-15 medium with 10% foetal bovine serum. Propagation of RSBF-2 cells was serum dependent and exhibited low plating efficiency ( (Source: Journal of Fish Diseases)

Susceptibility of koi × crucian carp and koi × goldfish hybrids to koi herpesvirus (KHV) and the development of KHV disease (KHVD)

Journal of Fish Diseases — Wed, 20 Jan 2010 00:00:00 +0100

Hybrids of koi, Cyprinus carpio × crucian carp, Carassius carassius and koi × goldfish, Carassius auratus, proved to be susceptible to koi herpesvirus (KHV, syn. CyHV-3) and developed KHV disease (KHVD). While hybrids of koi × goldfish were partly resistant to mortality following infection by immersion, most koi × crucian carp hybrids died after bath infection. KHV DNA was detected in dead fish but also in all surviving animals by different polymerase chain reactions (PCRs). According to these results, hybrid crossbreeding does not seem to prevent severe losses associated with KHV in terms of inducing KHVD. The present study showed severe losses after a waterborne KHV infection of between 35% and 100% in koi × goldfish and koi × crucian carp hybrids as well as in SPF carp. (Source: J...

Determination of minimal concentration of Piscirickettsia salmonis in water columns to establish a fallowing period in salmon farms

Journal of Fish Diseases — Tue, 19 Jan 2010 00:00:00 +0100

A highly sensitive real-time PCR procedure to detect and quantify the number of Pisciricketsia salmonis units in seawater samples from affected farm sites has been developed. The purpose was to determine a fallowing period that would allow safe restocking of the target farm with new fish. Bacterial load was determined in water samples by comparing the obtained amplification values against a standard curve generated by the amplification of known concentrations of the ITS-ribosomal component of P. salmonis DNA, cloned in a suitable vector. The standard curve was linear over the range of 101[ndash]1010 log units. Target samples were taken every 10 days over a 40-day period, at 5 m depth and at the surface. In a highly affected area of southern Chile, the number of bacterial units in farm wate...

Validation of a qPCR assay for the detection of Ictalurid herpesvirus-2 (IcHV-2) in fish tissues and cell culture supernatants

Journal of Fish Diseases — Mon, 18 Jan 2010 00:00:00 +0100

Ictalurid herpesvirus-2 (IcHV-2) is a pathogen of cultured black bullhead, Ameiurus melas (Rafinesque), and has been shown to produce high mortality in experimental exposures of channel catfish, Ictalurus punctatus (Rafinesque). During acute infections, the virus grows readily in cell cultures but produces a cytopathic effect (CPE) similar to that of Ictalurid herpesvirus-1 (IcHV-1) and the channel catfish reovirus. We have developed a quantitative PCR assay that can be used to detect IcHV-2 in fish tissues and cell culture supernatants. The assay does not amplify other fish herpesviruses tested or host DNA. It is quantitative over a range of eight logs, and the limit of detection is (Source: Journal of Fish Diseases)

The garlic component, allicin, prevents disease caused by Aeromonas hydrophila in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Sun, 17 Jan 2010 00:00:00 +0100

Allicin was fed at 0 (= control), 0.5 and 1.0 mL of Allimed® liquid 100 g[minus]1 of feed for 14 days to rainbow trout, Oncorhynchus mykiss (Walbaum), fingerlings before infection with Aeromonas hydrophila with a resultant reduction in mortalities from 80% in the controls to 8% [relative percentage survival (RPS) = 90%] and 0% (RPS = 100%) among the treated fish. Allicin was strongly antibacterial compared to the control, with a minimum inhibitory concentration (MIC) of >400 [mu]L mL[minus]1 of Allimed® liquid. Use of allicin led to a lower number of white blood cells (132.0 ± 0.4 × 103) compared to 175.0 ± 0.1 × 103 in the controls, but elicited increased phagocytic activity, i.e. a phagocytic value of 39.2% compared to 13.6% in the controls, and serum lysozyme activity, which showe...

The ZnuABC operon is important for Yersinia ruckeri infections of rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Tue, 12 Jan 2010 00:00:00 +0100

Signature-tagged mutagenesis was used to identify genes essential for survival of Yersinia ruckeri in its natural host, rainbow trout, Oncorhynchus mykiss. A mini-Tn5-Km2 signature-tagged mutant, C6-1, was missing from rainbow trout kidney at 7 days after an immersion challenge. The transposon insertion in C6-1 was in a homologue of the znuA gene of Escherichia coli that encodes ZnuA, a zinc-binding periplasmic protein of the high-affinity zinc transporter ZnuABC. Further sequencing of the C6-1 locus in Y. ruckeri identified homologues of two other genes: znuB, encoding a putative inner membrane permease, and znuC, encoding a putative ATPase. When present on a low-copy plasmid, the znuABC locus of Y. ruckeri fully restored growth of a zinc transport[ndash]deficient [Delta]znuABC mutant of ...

Relationships between growth and disease resistance in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Mon, 04 Jan 2010 00:00:00 +0100

Rainbow trout from 23 families were evaluated for growth and resistance to the bacterial coldwater disease (BCWD) caused by Flavobacterium psychrophilum and infectious haematopoietic necrosis (IHN) caused by IHN virus. Average family weights were between 161 and 263 g with an average of 225 g at 213 days post-fertilization with specific growth rates ranging from 2.37 to 2.88. Per cent survival of fish challenged with F. psychrophilum was between 18% and 100%, while for those challenged with IHNV, the range was between 12% and 93%. Significant positive correlations were found for end body weight and resistance to IHN (P < 0.05) and for early body weight and resistance to BCWD (P < 0.1). However, no significant correlations were detected between resistance to both pathogens or disease resist...

In vivo transfer of plasmid pRAS1 between Aeromonas salmonicida and Aeromonas hydrophila in artificially infected Cyprinus carpio L.

Journal of Fish Diseases — Sun, 03 Jan 2010 00:00:00 +0100

This study investigated the possible in vivo transfer of plasmid pRAS1 between Aeromonas salmonicida and A. hydrophila inhabiting two different organs of Cyprinus carpio L. To distinguish transconjugants from naturally occurring antibiotic resistant bacteria, twelve luminescent transposon-tagged A. hydrophila strains using miniTn5luxCDABEKm2 transposon were generated. In conjugal transfer experiments, fish were conditioned with the donor bacteria and subsequently immersed in water containing the recipient strain. Bacteria were recovered from gills and intestines and isolated by growth on selective plates. Transconjugants were identified by their resistance to the pRAS1 encoded antimicrobials and by light emission. In vivo transfer frequencies ranged between 10[minus]3 and 10[minus]6 and we...

Genetic diversity and antimicrobial resistance of Flavobacterium psychrophilum isolated from cultured rainbow trout, Onchorynchus mykiss (Walbaum), in Spain

Journal of Fish Diseases — Sun, 03 Jan 2010 00:00:00 +0100

In this study, to investigate genetic variability of this bacterium, pulsed-field gel electrophoresis after DNA digestion with endonuclease StuI, plasmid profiling analysis and antimicrobial susceptibility testing were undertaken with 25 isolates of F. psychrophilum from Spain. These isolates were classified into 17 patterns by PFGE analysis, which were grouped into four clusters and seven independent branches. Twenty isolates (80%) possessed plasmids of 3.5 kb (n = 13) or 5.5 kb (n = 7). No plasmids were associated with antibiotic resistance to oxytetracycline (OTC) or florfenicol (FLO). Twenty isolates (80%) had minimum inhibitory concentrations (MICs) to OTC of between 2.4 and 9.7 [mu]g mL[minus]1, and all isolates were susceptible to FLO. A relationship between the origin of the isolat...

A study of gross, histological and blood biochemical changes in rainbow trout, Oncorhynchus mykiss (Walbaum), with rainbow trout gastroenteritis (RTGE)

Journal of Fish Diseases — Sun, 03 Jan 2010 00:00:00 +0100

This study examined the macroscopic and microscopic changes in trout with RTGE (RTGE+), as well as the blood chemistry. A total of 464 rainbow trout were sampled from 11 sites in the UK, comprising 152 RTGE+ fish and 330 random, apparently healthy fish. A case definition for RTGE was assessed by the analysis of its agreement with three laboratory tests: histopathology, packed cell volume and kidney bacteriology. Cluster analysis indicated the presence of three distinct presentations within the population of RTGE+ fish. Cluster A included gross signs associated with moribund RTGE+ fish, and clusters B and C identified gross signs consistent with concurrent diseases, notably furunculosis, enteric redmouth and proliferative kidney disease. The information gained was used to select RTGE+ fish ...

Detection of infectious pancreatic necrosis virus (IPNV) from asymptomatic redbanded seabream, Pagrus auriga Valenciennes, and common seabream, Pagrus pagrus (L.), using a non-destructive procedure

Journal of Fish Diseases — Sun, 03 Jan 2010 00:00:00 +0100

A non-destructive procedure based on nested RT-PCR and dot-blot hybridization has been developed for the detection of asymptomatic IPNV-carrier fish. The pair of primers designed for RT-PCR amplified a 599-bp fragment of the pVP2 region within the polyprotein gene, resulting in the detection of IPNV genotype III.1. The use of a nested RT-PCR allowed the amplification of IPNV genotypes III.1 and I.2. In addition, a 191-bp probe was designed for hybridization studies used in combination with the nested RT-PCR. The application of the nested RT-PCR to analyse blood samples from asymptomatic redbanded seabream, Pagrus auriga, and common seabream, P. pagrus, specimens showed a 53.1% and 77.8% prevalence of IPNV-carriers, respectively. The combination of nested RT-PCR and dot-blot hybridization i...

Iridovirus infections in finfish – critical review with emphasis on ranaviruses

Journal of Fish Diseases — Tue, 29 Dec 2009 00:00:00 +0100

Viruses in three genera of the family Iridoviridae (iridoviruses) affect finfish. Ranaviruses and megalocytiviruses are recently emerged pathogens. Both cause severe systemic disease, occur globally and affect a diversity of hosts. In contrast, lymphocystiviruses cause superficial lesions and rarely cause economic loss. The ranavirus epizootic haematopoietic necrosis virus (EHNV) from Australia was the first iridovirus to cause epizootic mortality in finfish. Like other ranaviruses, it lacks host specificity. A distinct but closely related virus, European catfish virus, occurs in finfish in Europe, while very similar ranaviruses occur in amphibians in Europe, Asia, Australia, North America and South America. These viruses can be distinguished from one another by conserved differences in th...

Amoebic gill disease resistance is not related to the systemic antibody response of Atlantic salmon, Salmo salar L.

Journal of Fish Diseases — Thu, 26 Nov 2009 00:00:00 +0100

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 individuals over the first three rounds of natural AGD infection and from survivors of a subsequent non-intervention AGD survival challenge. The systemic immune reaction to 'wildtype'Neoparamoeba sp. was characterized by Western blot analysis and differentiated to putative carbohydrate or peptide epito...

Three tetraspanins from Chinese shrimp, Fenneropenaeus chinensis, may play important roles in WSSV infection

Journal of Fish Diseases — Tue, 24 Nov 2009 00:00:00 +0100

Three members of the tetraspanin/TM4SF superfamily were cloned from Chinese shrimp, Fenneropenaeus chinensis. The deduced amino acid sequences of the three proteins have typical motifs of the tetraspanin/TM4SF superfamily. Phylogenetic analysis of the proteins, together with the known tetraspanins of invertebrates and vertebrates, revealed that they belong to different tetraspanin subfamilies: CD9, CD63 and tetraspanin-3. The three cloned genes of CD9, CD63 and tetraspanin-3 showed apparently different tissue distributions. The CD9 gene (FcCD9) was specifically expressed in the hepatopancreas. While for the CD63 gene (FcCD63), the highest expression was detected in nerves, epidermis and heart, with low expression in haemocytes, ovary, gill, hepatopancreas and stomach and no expression in i...

An analysis of levels of infectious pancreatic necrosis virus in Atlantic salmon, Salmo salar L., broodstock in Scotland between 1990–2002

Journal of Fish Diseases — Fri, 20 Nov 2009 00:00:00 +0100

Throughout this study period the prevalence of infectious pancreatic necrosis virus (IPNV) in Scottish farmed Atlantic salmon was high in the marine environment but relatively low in fresh water. In order to minimize the risk of vertical transmission of infection from parent to progeny, all IPNV infected broodstock populations had to undergo testing of all fish for the virus at the time of stripping and eggs from positive parents were destroyed. Between 1990 and 2002 over 68 000 Atlantic salmon broodfish were individually screened for IPNV by cell culture isolation and enzyme linked immunosorbent assay. Generalized linear mixed models were used to assess the influence of geographical region, age, sex and year on IPNV prevalence in Atlantic salmon broodstock. This analysis determined that t...

Establishment, characterization, virus susceptibility and transfection of cell lines from cobia, Rachycentron canadum (L.), brain and fin

Journal of Fish Diseases — Wed, 18 Nov 2009 00:00:00 +0100

Establishment and characterization of two cobia, Rachycentron canadum, cell lines derived from cobia brain (CB) and cobia fin (CF) are described. Caudal fin and brain from juvenile cobia were dissociated for 30 and 10 min, respectively, in phosphate-buffered saline containing 0.25% trypsin at 25 °C. The optimal culture condition for both dissociated cells (primary cell culture) was at 28 °C in Leibovitz-15 medium containing 10% foetal bovine serum. The cells have been sub-cultured at a ratio of 1:2 for more than 160 passages over a period of 3 years. Origin of the cultured cells was verified by comparison of their sequences of mitochondrial cytochrome oxidase subunit I genes (cox I) with the cox 1 sequence from cobia muscle tissue. The cell lines showed polyploidy. No mycoplasma contamin...

A comparative molecular study of the presence of "Candidatus arthromitus" in the digestive system of rainbow trout, Oncorhynchus mykiss (Walbaum), healthy and affected with rainbow trout gastroenteritis

Journal of Fish Diseases — Fri, 13 Nov 2009 00:00:00 +0100

Observations were made using histopathological techniques in conjunction with a nested polymerase chain reaction (PCR) protocol for the specific detection of "Candidatus arthromitus" on DNA extracted from wax-embedded tissues and fresh digestive contents of rainbow trout. Samples positive for "Candidatus arthromitus" DNA included fish with rainbow trout gastroenteritis (RTGE), clinically normal cohabiting fish, and apparently healthy controls from RTGE positive and RTGE negative sites. The results obtained from the PCR were confirmed by nucleotide sequencing. "Candidatus arthromitus" DNA was found in distal intestine as well as in sections of pyloric caeca, suggesting that both these locations are appropriate for molecular detection of "Candidatus arthromitus" DNA in trout. Furthermore, ra...

Cellular components of probiotics control Yersinia ruckeri infection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

Subcellular components of the probiotics Aeromonas sobria GC2 and Bacillus subtilis JB-1, when administered to rainbow trout, Oncorhynchus mykiss, conferred protection against a new biogroup of Yersinia ruckeri. Thus, intraperitoneal or intramuscular injection of rainbow trout with cell wall proteins (CWPs), outer membrane proteins (OMPs), lipopolysaccharides (LPS), whole cell proteins (WCPs) and live cells followed by challenge on day 8 with Y. ruckeri led to 80[ndash]100% survival compared with 10% survival in the controls. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles of WCPs and OMPs from GC2 had 10 and 5 variable protein bands in comparison to 11 and 5 bands in the WCPs and CWPs from JB-1. Proteomic analyses were employed following SDS-PAGE to categori...

Utilization of tissue habitats by Myxobolus wulii Landsberg & Lom, 1991 in different carp hosts and disease resistance in allogynogenetic gibel carp: redescription of M. wulii from China and Japan

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

Myxobolus wulii (=Myxosoma magna) was first described from the gills of goldfish, Carassius auratus auratus, in China. Subsequently, a myxosporean infecting the hepatopancreas of allogynogenetic gibel carp, C. auratus gibelio, was designated as a different species, Myxobolus guanqiaoensis, although the morphological features were almost identical to those of M. wulii. In Japan, an unidentified Myxobolus sp. was found in the gills and hepatopancreas of goldfish. Morphological and molecular analyses in the present study identified these myxosporeans as M. wulii, which was thus shown to use different habitats in the host fish. Phylogenetic analyses of small subunit ribosomal RNA gene sequences showed that M. wulii is closely related to two gill-infecting Myxobolus species, M. ampullicapsulatu...

Host response to the chondracanthid copepod Chondracanthus goldsmidi, a gill parasite of the striped trumpeter, Latris lineata (Forster), in Tasmania

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

In this study C. goldsmidi was associated with extensive epithelial hyperplasia and necrosis. Pathological changes were most pronounced near the parasite's attachment site, with papilloma-like growths surrounding the entire parasite resulting in deformation of the filament. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. Mast cells were absent in healthy gills; in contrast numerous mast cells were identified in the papilloma-like growths. Immunostaining identified piscidin-positive mast cells in the papilloma-like growths, presenting the first evidence of piscidin in the family Latridae. (Source: Journal of Fish Diseases)

A sensitive FRET probe assay for the selective detection of Mycobacterium marinum in fish

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

Mycobacterium marinum is the causative agent of mycobacteriosis in wild and cultured fish and of atypical infection in humans. For the diagnosis of M. marinum, cultural and traditional polymerase chain reaction (PCR) methods are currently used. However, these protocols, although able to discriminate within Mycobacterium spp., have proved to be time-consuming or difficult to carry out. For this reason, the aim of this study was to obtain a rapid and specific diagnostic tool to quantify fish Mycobacterium spp. or to discriminate M. marinum from other mycobacteria. A primary PCR amplification with SYBR Green had a detection limit (dl) of 102Mycobacterium DNA copies with a log-linear quantification range up to 104 (R2 = 0.99). The second PCR using FRET probes, flanking a region containing spec...

Attenuated Mycobacterium marinum protects zebrafish against mycobacteriosis

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

(Source: Journal of Fish Diseases)

Complete sequencing of Tunisian redspotted grouper nervous necrosis virus betanodavirus capsid gene and RNA-dependent RNA polymerase gene

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

This study reports on the characterization of the full RNA2 sequence of a Tunisian betanodavirus with a length of 1433 nt, containing a 339 amino acid open-reading frame encoding the CP, and typing to the redspotted grouper nervous necrosis virus Ia genotype following phylogenetic analysis. The homology of the capsid protein to other betanodaviruses or alphanodaviruses was compared. In addition, a full length RNA1 sequence of 3104 nt encoding a 982 amino acid RNA-dependent RNA polymerase was obtained. (Source: Journal of Fish Diseases)

Mycobacteria isolated from Chesapeake Bay fish

Journal of Fish Diseases — Tue, 10 Nov 2009 00:00:00 +0100

Mycobacteriosis in fish can result in ulcers, emaciation, and in some cases death. Mycobacteria have been previously isolated from a variety of Chesapeake Bay fish species, and the current study was designed to identify potential host specificity and location fidelity of mycobacterial isolates. Mycobacteria were isolated from wild fish of the Chesapeake Bay collected from the Upper Bay, the Choptank River, Herring Bay, the Chicamacomico River, the Pocomoke River and the Potomac River in 2003[ndash]2006. Mycobacterial isolates were recovered from striped bass, Morone saxatilis, Atlantic menhaden, Brevoortia tyrannus, white perch, Morone americana, summer flounder, Paralichthys dentatus, spot, Leiostomus xanthurus, largemouth bass, Micropterus salmoides, channel catfish, Ictalurus punctatus,...

Outbreaks of viral nervous necrosis in juvenile and adult farmed Atlantic cod, Gadus morhua L., in Norway

Journal of Fish Diseases — Thu, 05 Nov 2009 00:00:00 +0100

(Source: Journal of Fish Diseases)

Myxobolus notropis from emerald shiner, Notropis atherinoides Rafinesque, in Lake Superior

Journal of Fish Diseases — Mon, 02 Nov 2009 00:00:00 +0100

(Source: Journal of Fish Diseases)

Koi herpesvirus: distribution and prospects for control in England and Wales

Journal of Fish Diseases — Fri, 30 Oct 2009 00:00:00 +0100

This study aimed to determine the geographic distribution and prevalence of KHV exposed fish in England and Wales through ELISA antibody testing. Only three of the 82 farms sampled produced positive results, suggesting fish farms provide a relatively safe source of fish. Of the 71 'high-risk' fisheries tested, 26 were positive. All eight geographic areas within England and Wales studied had at least one KHV positive site. Twelve consignments of imported koi carp from seven S.E. Asian countries were tested for KHV antibody. Six consignments from six different countries were positive. Although a high proportion of consignments were positive, the results indicate that lower risk stocks of fish exist that could be sourced by the ornamental carp sector. The study provides evidence that KHV is w...

Tunic morphology and viral surveillance in diseased Korean ascidians: soft tunic syndrome in the edible ascidian, Halocynthia roretzi (Drasche), in aquaculture

Journal of Fish Diseases — Fri, 30 Oct 2009 00:00:00 +0100

'Soft tunic syndrome' causes mass mortality in the edible ascidian Halocynthia roretzi in Korean and Japanese aquaculture. In histopathological comparison, there were no specific differences between diseased specimens from Korea and Japan, indicating that soft tunic syndrome occurring in Korea and Japan is the same disease. No bacterial or protozoan cells were microscopically detected in either healthy or diseased tunics suggesting they are not the direct causes of soft tunic syndrome. Attempts were made to isolate virus from affected ascidians taking into account temperature conditions in which soft tunic syndrome is most prevalent in the field. However, no viruses were isolated from diseased or non-diseased specimens using chinook salmon embryo (CHSE-214), flounder fin (FFN) or epithelio...

First isolation of Tenacibaculum soleae from diseased cultured wedge sole, Dicologoglossa cuneata (Moreau), and brill, Scophthalmus rhombus (L.)

Journal of Fish Diseases — Fri, 30 Oct 2009 00:00:00 +0100

(Source: Journal of Fish Diseases)

In vitro markers for virulence in Yersinia ruckeri

Journal of Fish Diseases — Fri, 30 Oct 2009 00:00:00 +0100

In this study, different traits that have been associated with bacterial virulence were studied in Yersinia ruckeri. Two isolates that had been shown to cause disease and mortality in experimentally infected rainbow trout were compared with five avirulent isolates. Both virulent isolates showed high adhesion to gill and intestinal mucus of rainbow trout, whereas the majority of non-virulent strains demonstrated significantly lower adhesion. A decrease in adherence capability following bacterial treatment with sodium metaperiodate and proteolytic enzymes suggested the involvement of carbohydrates and proteins. All strains were able to adhere to and invade chinook salmon embryo cell line (CHSE-214), fathead minnow epithelial cell line (FHM) and rainbow trout liver cell line (R1). One non-vir...

The effect of liposome-coated recombinant protein VP28 against white spot syndrome virus in kuruma shrimp, Marsupenaeus japonicus

Journal of Fish Diseases — Thu, 03 Sep 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Phenotypic, serological and molecular evidence of Chryseobacterium piscicola in farmed Atlantic salmon, Salmo salar L., in Finland

Journal of Fish Diseases — Thu, 03 Sep 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Exophiala xenobiotica infection in cultured striped jack, Pseudocaranx dentex (Bloch & Schneider), in Japan

Journal of Fish Diseases — Thu, 03 Sep 2009 23:00:00 +0100

This report describes Exophiala infection in cultured striped jack, Pseudocaranx dentex, in Japan in 2005. One hundred out of 35 000 fish died per day and mortalities continued for 1 month. Diseased fish showed swelling of the abdomen and kidney distension. Numerous septate hyphae, pale brown in colour, were seen in kidney in squash preparations. Histology revealed abundant fungal hyphae and conidia in gill, heart and kidney. Fungal hyphae were accompanied by cell necrosis and influx of inflammatory, mainly mononuclear cells. The fungus isolated from the diseased fish had septate hyphae, pale brown in colour and 1.8[ndash]3.0 [mu]m in diameter. Conidiogenous cells were conspicuous annellides, short or cylindrical or fusiform in shape. Conidia were one-celled, ellipsoidal with smooth walls,...

Pharmacokinetics of emamectin benzoate administered to Atlantic salmon, Salmo salar L., by intra-peritoneal injection

Journal of Fish Diseases — Sun, 30 Aug 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Experimental studies confirm the wide host range of the Great Lakes viral haemorrhagic septicaemia virus genotype IVb

Journal of Fish Diseases — Sat, 29 Aug 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Book review

Journal of Fish Diseases — Sat, 29 Aug 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Prospective longitudinal studies of salmonid alphavirus infections on two Atlantic salmon farms in Ireland; evidence for viral persistence

Journal of Fish Diseases — Sat, 29 Aug 2009 23:00:00 +0100

Prospective longitudinal studies of two outbreaks of pancreas disease in Atlantic salmon (AS), Salmo salar L., in Ireland were conducted. Both outbreaks occurred during the marine phase of production, with one caused by salmonid alphavirus subtype 1 (SAV1) and the other by SAV4. In addition to screening a range of tissues by real-time reverse transcriptase polymerase chain reaction (RRT-PCR), virological, serological and histopathological examinations were performed along with partial genome sequencing and results were related to environmental and production data and farm history. On Farm 1 (marine sampling only), infection was detected within 3 weeks of smolts being placed on the farm, while on Farm 2 (freshwater and marine sampling), infection was first detected 315 days after transfer t...

A single-dose pharmacokinetic study of emamectin benzoate in cod, Gadus morhua L., held in sea water at 9 °C

Journal of Fish Diseases — Sat, 29 Aug 2009 23:00:00 +0100

The pharmacokinetic profile of the antiparasitic agent emamectin benzoate was studied in plasma after intravenous (i.v.) injection and in plasma, muscle and skin following oral (p.o.) administration to cod, Gadus morhua, held in sea water at 9 °C and weighing 100[ndash]200 g. Following i.v. injection, the plasma drug concentration-time profile showed two distinct phases. The plasma distribution half-life (t1/2[alpha]) was estimated as 2.5 h, the elimination half-life (t1/2[beta]) as 216 h, the total body clearance (ClT) as 0.0059 L kg[minus]1 h[minus]1 and mean residence time (MRT) as 385 h. The volume of distribution at steady state, Vd(ss), was calculated to be 1.839 L kg[minus]1. Following p.o. administration the peak plasma concentration (Cmax) was 15 ng mL[minus]1, the time to peak p...

An experimental vaccine against Aeromonas hydrophila can induce protection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Sat, 29 Aug 2009 23:00:00 +0100

A candidate vaccine against Aeromonas hydrophila in rainbow trout, Oncorhynchus mykiss, was developed using a bacterial lysate. To test the strength of protection, A. hydrophila challenge models were compared using injection into both the intraperitoneal (IP) cavity and the dorsal sinus (DS) with selected doses of live bacteria washed in saline or left untreated. Unlike the IP route, injection into the DS with either saline washed or unwashed cells resulted in consistent cumulative mortality and a dose response that could be used to establish a standard challenge having an LD50 of approximately 3 × 107 colony forming units per fish. Survivors of the challenge suffered significantly lower mortality upon re-challenge than naïve fish, suggesting a high level of acquired resistance was elici...

Intensive infestations of Sciaenocotyle pancerii (Monogenea, Microcotylidae) on Argyrosomus regius (Asso) under fish-farming conditions

Journal of Fish Diseases — Thu, 20 Aug 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Intramyocardial dissecting haemorrhage in farmed rainbow trout Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Wed, 19 Aug 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Challenge studies of European stocks of redfin perch, Perca fluviatilis L., and rainbow trout, Oncorhynchus mykiss (Walbaum), with epizootic haematopoietic necrosis virus

Journal of Fish Diseases — Wed, 19 Aug 2009 23:00:00 +0100

A challenge model for comparison of the virulence of epizootic haematopoietic necrosis virus (EHNV) to European stocks of redfin perch, Perca fluviatilis L., and rainbow trout, Oncorhynchus mykiss (Walbaum), was tested. The model investigated intraperitoneal (IP), bath and cohabitation routes at 10, 15 and 20 °C for 5[ndash]6 g fish and 15 °C for 20 g perch. In the IP challenges of perch, significant mortality occurred at 15 °C and 20 °C. In challenge trials for rainbow trout, significant mortalities were observed in IP and bath challenges at 20 °C. The mortality observed in IP challenged 20 g perch was not significantly different from that recorded for 6 g fish challenged IP. No significant mortality was observed in any other treatment groups. Re-isolation of ranavirus was confirmed ...

Antigenic differences of the scuticociliate Miamiensis avidus from Japan

Journal of Fish Diseases — Wed, 19 Aug 2009 23:00:00 +0100

In this study, we elucidated the antigenic differences between six Japanese M. avidus isolates as an initial step toward developing an effective vaccine against the disease. Four Japanese flounder isolates (IyoI, Nakajima, JF05To and Mie0301 isolates), one spotted knifejaw, Oplegnathus punctatus, isolate (SK05Kyo), and one ridged-eye flounder, Pleuronichthys cornutus, isolate (RF05To) were subjected to serological analysis. Antisera against IyoI, SK05Kyo, Nakajima and Mie0301 isolates were raised in rabbits and used for immobilization assays and Western blotting. Immobilization assays showed that the six isolates could be divided into three groups, tentatively designated serotype I for IyoI, JF05To, RF05To, SK05Kyo, serotype II for Nakajima and serotype III for Mie0301. Western blotting re...

In vitro efficacy of praziquantel against the cercariae of Diplostomum sp., Rhipidocotyle fennica and R. campanula

Journal of Fish Diseases — Mon, 13 Jul 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Development and characterization of a monoclonal antibody against Taura syndrome virus

Journal of Fish Diseases — Sun, 12 Jul 2009 23:00:00 +0100

We produced a panel of monoclonal antibodies (MAbs) from the fusion of Taura syndrome virus variants from Belize (TSV-BZ) immunized BALB/cJ mouse spleen cells and non-immunoglobulin secreting SP2/0 mouse myeloma cells. One antibody, 2C4, showed strong specificity and sensitivity for TSV in dot-blot immunoassay and immunohistochemistry (IHC) analysis. The MAb reacted against native TSV-BZ, TSV variants from Sinaloa, Mexico (TSV-SI) and TSV variants from Hawaii (TSV-HI) in dot-blot immunoassay. By IHC, the antibody identified the virus in a pattern similar to the digoxigenin-labelled TSV-cDNA probe for the TSV-BZ, TSV-HI and TSV-SI variants, but not for the TSV variants from Venezuela (TSV-VE) and the TSV variants from Thailand (TSV-TH). MAb 2C4 did not react against other shrimp pathogens o...

Identification and pathogenicity to rainbow trout, Oncorhynchus mykiss (Walbaum), of some aeromonads

Journal of Fish Diseases — Thu, 09 Jul 2009 23:00:00 +0100

Twelve strains of fish pathogenic aeromonads were identified by 16S rRNA sequencing as Aeromonas bestiarum, A. hydrophila, A. hydrophila subsp. dhakensis, A. salmonicida subsp. salmonicida, A. sobria biovar sobria and A. veronii biovar sobria. Following intramuscular injection, A. hydrophila subsp. dhakensis caused dark liquefying, raised furuncle-like lesions in rainbow trout within 48 h. Extracellular products of all cultures contained gelatinase and lecithinase, and most revealed lipase. Congo red absorption and siderophore production was recorded, but not so the suicide phenomenon or slime production. Sodium dodecyl sulphate polyacrylamide gel electrophoresis profile of the outer membrane proteins (OMP) revealed 10[ndash]25 bands, of which major bands were seen in the region of 32.5[nd...

Melanomacrophages in three species of free-ranging sharks from the northwestern Atlantic, the blue shark Prionacae glauca (L.), the shortfin mako, Isurus oxyrhinchus Rafinesque, and the thresher, Alopias vulpinus (Bonnaterre)

Journal of Fish Diseases — Thu, 09 Jul 2009 23:00:00 +0100

The melanomacrophage aggregates or cells (MMC) are commonly used as biomarkers of exposure to pollution in fish, albeit their numbers and morphological characteristics can be influenced not only by environmental toxins but also by a range of physiological parameters and pathological conditions. Accordingly, before we can use MMC as biomarkers in any fish species, their normal, 'background' characteristics have to be established in apparently healthy fish. The knowledge of MMC in sharks is minimal. The aim of this study was to characterize MMC from 51 free-ranging, large pelagic sharks from the northwestern Atlantic, including shortfin mako, Isurus oxyrhinchus, thresher, Alopias vulpinus and blue shark, Prionacae glauca. The rationale of this study was twofold. First, because, sharks have l...

Increased survival by feeding tetradecylthioacetic acid during a natural outbreak of heart and skeletal muscle inflammation in S0 Atlantic salmon, Salmo salar L.

Journal of Fish Diseases — Thu, 09 Jul 2009 23:00:00 +0100

We have previously documented increased survival by feeding tetradecylthioacetic acid (TTA) during a natural outbreak of infectious pancreatic necrosis in post-smolt S1 Atlantic salmon. The aim of the present study was to test the effects of dietary TTA in S0 smolt at a location where fish often experience natural outbreaks of heart and skeletal muscle inflammation (HSMI) during their first spring at sea. The experimental groups were fed a diet supplemented with 0.25% TTA for a 6-week period prior to a natural outbreak of HSMI in May 2007. Relative percent survival for the groups fed TTA was 45% compared with control diets, reducing mortality from 4.7% to 2.5%. Expression of genes related to lipid oxidation was higher in cardiac ventricles from salmon fed TTA compared with controls. In add...

Molecular differentiation of infectious pancreatic necrosis virus isolates from farmed and wild salmonids in Ireland

Journal of Fish Diseases — Thu, 09 Jul 2009 23:00:00 +0100

This study investigated the genotypes and sub-groups of infectious pancreatic necrosis virus (IPNV) present in farmed and wild salmonid fish in Ireland. An 1100-bp portion of the VP2 region of segment A from each of 55 IPNV isolates collected over 2003[ndash]2007 was amplified by reverse-transcription[ndash]polymerase chain reaction and the product directly sequenced. The nucleotide sequences of each isolate were aligned and compared with each other and with the corresponding sequences of a number of reference isolates. All the 55 sequenced isolates belonged to genogroup 5 (Sp serotype) and could be divided into two subgroups. Irish subgroup 1 consisted of isolates from farmed salmon originating from an Irish salmon broodstock. Irish subgroup 2 consisted of isolates from imported farmed st...

Comparison of the resistance of selected families of common carp, Cyprinus carpio L., to koi herpesvirus: preliminary study

Journal of Fish Diseases — Mon, 06 Jul 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Caspase-dependent induction of apoptosis in barramundi, Lates calcarifer (Bloch), muscle cells by grouper iridovirus

Journal of Fish Diseases — Mon, 06 Jul 2009 23:00:00 +0100

We recently reported that grouper iridovirus (GIV) can induce apoptosis in barramundi, Lates calcarifer, muscle (BM) and swim bladder (BSB) cell lines. In this paper, we further characterize the molecular mechanism underlying apoptotic death in BM cells triggered by GIV. DNA-laddering and apoptotic cells were observed in BM cells infected with UV-irradiated or untreated GIV but was absent in cells infected with heat-inactivated GIV, indicating the involvement of viral protein in the apoptosis event. In GIV-infected BM cells, the conversion of procaspase-3 to caspase-3 was evident and the level of caspase-8 and -9 increased as early as 30 min post-infection. When treated with a pancaspase inhibitor, the GIV-induced apoptosis event was abolished. These observations indicate that GIV-induced ...

Isolation of a novel strain of Bacillus pumilus from penaeid shrimp that is inhibitory against marine pathogens.

Journal of Fish Diseases — Sat, 04 Jul 2009 23:00:00 +0100

A bacterium was isolated from the mid-gut of healthy black tiger shrimp, Penaeus monodon, based on a large zone of inhibition in mixed culture on solid medium. The isolate was a Gram-positive, motile spore former, with an optimum pH range for growth in tryptone soya broth containing 2% NaCl of between pH 6 and 9. The bacterium was highly salt tolerant with concentrations between 0% and 8% having no detrimental effect on growth. The isolate was identified as Bacillus pumilus based on physiological capabilities using the API50CHB and Biolog systems. Amplification and sequencing of the 16S rRNA gene followed by phylogenetic analysis confirmed its identity. The Bacillus pumilus isolate was strongly inhibitory against the marine bacterial pathogens Vibrio alginolyticus, V. mimicus and V. harvey...

Effects of temperature on disease progression and swimming stamina in Ichthyophonus-infected rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Tue, 30 Jun 2009 23:00:00 +0100

This study helps explain field observations showing the recent emergence of clinical ichthyophoniasis in Yukon River Chinook salmon later in their spawning migration when water temperatures were high, as well as the apparent failure of a substantial percentage of infected fish to successfully reach their natal spawning areas. (Source: Journal of Fish Diseases)

FishPathogens.eu/vhsv: a user-friendly viral haemorrhagic septicaemia virus isolate and sequence database

Journal of Fish Diseases — Wed, 24 Jun 2009 23:00:00 +0100

A database has been created, http://www.FishPathogens.eu, with the aim of providing a single repository for collating important information on significant pathogens of aquaculture, relevant to their control and management. This database will be developed, maintained and managed as part of the European Community Reference Laboratory for Fish Diseases function. This concept has been initially developed for viral haemorrhagic septicaemia virus and will be extended in future to include information on other significant aquaculture pathogens. Information included for each isolate comprises sequence, geographical origin, host origin and useful key literature. Various search mechanisms make it easy to find specific groups of isolates. Search results can be presented in several different ways inclu...

Genetic heterogeneity of betanodaviruses in juvenile production trials of Pacific bluefin tuna, Thunnus orientalis (Temminck & Schlegel)

Journal of Fish Diseases — Tue, 16 Jun 2009 23:00:00 +0100

In this study, we examined the genetic variability of betanodaviruses detected in the diseased juveniles to understand the transmission of the disease in a tuna hatchery. A total of 94 nucleotide sequences of betanodavirus (partial sequence of the coat protein gene, RNA2) were obtained from fish samples by reverse-transcriptase polymerase chain reaction amplification and 13 haplotypes were recognized among the sequences. The haplotype distributions in the viral populations from the diseased juveniles were related to the broodstocks from which the juveniles originated, suggesting that vertical transmission had occurred in the hatchery. The statistical parsimony network of viral haplotypes suggests that the nucleotide substitutions among the samples were accumulated in a recent population gr...

Development of a method for the detection of infectious myonecrosis virus by reverse-transcription loop-mediated isothermal amplification and nucleic acid lateral flow hybrid assay

Journal of Fish Diseases — Mon, 15 Jun 2009 23:00:00 +0100

We report the development of a reverse-transcription loop-mediated isothermal amplification and nucleic acid lateral flow method (RT-LAMP-NALF) for detection of infectious myonecrosis virus (IMNV). The RT-LAMP-NALF method combines simplified nucleic acid extraction, a reverse-transcription loop-mediated isothermal amplification platform, and one-step visual colorimetric confirmation of the IMNV amplified sequences using a generic NALF qualitative detection test strip. The sensitivity of RT-LAMP (using two and three primer pairs) and nested RT-LAMP (using three primer pairs) was compared by real-time reverse-transcription-polymerase chain reaction (RT-PCR) using TaqMan probe. The detection of RT-LAMP (three primer pairs) products was accomplished by using a NALF-test strip. The RT-LAMP-NALF...

Husbandry stress exacerbates mycobacterial infections in adult zebrafish, Danio rerio (Hamilton)

Journal of Fish Diseases — Mon, 15 Jun 2009 23:00:00 +0100

Mycobacteria are significant pathogens of laboratory zebrafish, Danio rerio (Hamilton). Stress is often implicated in clinical disease and morbidity associated with mycobacterial infections but has yet to be examined with zebrafish. The aim of this study was to examine the effects of husbandry stressors on zebrafish infected with mycobacteria. Adult zebrafish were exposed to Mycobacterium marinum or Mycobacterium chelonae, two species that have been associated with disease in zebrafish. Infected fish and controls were then subjected to chronic crowding and handling stressors and examined over an 8-week period. Whole-body cortisol was significantly elevated in stressed fish compared to non-stressed fish. Fish infected with M. marinum ATCC 927 and subjected to husbandry stressors had 14% cum...

First isolation and characterization of Lactococcus garvieae from Brazilian Nile tilapia, Oreochromis niloticus (L.), and pintado, Pseudoplathystoma corruscans (Spix & Agassiz)

Journal of Fish Diseases — Mon, 15 Jun 2009 23:00:00 +0100

Lactococcus garvieae infection in cultured Nile tilapia, Oreochromis niloticus (L.), and pintado, Pseudoplathystoma corruscans (Spix & Agassiz), from Brazil is reported. The commercial bacterial identification system, Biolog Microlog®, confirmed the identity of L. garvieae. Infectivity trials conducted in Nile tilapia using Brazilian Nile tilapia L. garvieae isolates resulted in a median lethal dose-50 of 1.4 × 105 colony-forming units (CFU)/fish. This is the first evidence of the presence of this pathogen from Brazilian fish. In addition, this is the first report of L. garvieae infection in either Nile tilapia or pintado. Collectively, this evidence expands the geographical range of fish hosts, number of fish hosts harbouring L. garvieae and carbon source utilization by L. garvieae fish...

Effect of extracellular products of Tenacibaculum maritimum in Atlantic salmon, Salmo salar L.

Journal of Fish Diseases — Sun, 14 Jun 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Fitness and virulence of different strains of white spot syndrome virus

Journal of Fish Diseases — Sun, 14 Jun 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Comparison of histological features, and description of histopathological lesions in thyroid glands from three species of free-ranging sharks from the northwestern Atlantic, the blue shark, Prionace glauca (L.), the shortfin mako, Isurus oxyrhinchus Rafinesque, and the thresher, Alopias vulpinus (Bonnaterre)

Journal of Fish Diseases — Sun, 14 Jun 2009 23:00:00 +0100

Histomorphological features of piscine thyroids are widely accepted and frequently used as bioindicators of environmental pollution. This despite the fact that there is marked variation in thyroid morphology resulting from numerous pathological and physiological conditions. Our hypothesis was that there will be variations in histological features in thyroids collected from different shark species during the summer season in the northwestern Atlantic. To test our hypothesis, we examined histological features encountered in grossly normal thyroids from three species of sharks, the shortfin mako, Isurus oxyrhinchus, thresher, Alopias vulpinus and blue sharks, Prionace glauca. In addition, microscopic lesions from these thyroids were described. Ninety-four sharks were collected in summer 2001,...

Idiopathic cardiac pathology in seawater-farmed rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Sun, 14 Jun 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Lateral line depigmentation (LLD) in channel catfish, Ictalurus punctatus (Rafinesque)

Journal of Fish Diseases — Sun, 14 Jun 2009 23:00:00 +0100

We present microbiological, immunological and histopathological features of this lesion in channel catfish, Ictalurus punctatus (Rafinesque), that developed after exposure to a chronic nutritional stress. Depigmention was limited to skin that was adjacent to the lateral line. The epidermis of affected fish was thin and reduced to a one-cell-thick layer over the lateral line. Melanocytes were depleted at the dermo-epidermal junction and formed aggregates in the epidermis. Innate immunity was weaker in affected fish than that previously measured in well-fed channel catfish. Because the pathology and apparent aetiology of HLLE described in various fish species are highly variable, HLLE appears to be a clinical sign, rather than a disease or syndrome. Thus, we propose that this clinical sign b...

Francisella sp., an emerging pathogen of tilapia, Oreochromis niloticus (L.), in Costa Rica

Journal of Fish Diseases — Mon, 08 Jun 2009 23:00:00 +0100

Francisella sp. is an emergent bacterial pathogen that causes acute to chronic disease in warm and cold water cultured and wild fish species. During the past 3 years, the bacterium has been detected in tilapia, Oreochromis niloticus, cultured in Costa Rica. Infected fish presented non-specific clinical signs, such as erratic swimming, anorexia, anaemia, exophthalmia and high mortality. Upon macroscopic and microscopic examination, several internal organs (mainly spleen and kidney) were enlarged and contained white nodules. Histological examination revealed the presence of multifocal granulomatous lesions, with the presence of numerous small, pleomorphic, cocco-bacilli. The bacteria were isolated from infected tilapia on selective media and grown on several media with and without antibiotic...

Feeding Artemia franciscana (Kellogg) larvae with bacterial heat shock protein, protects from Vibrio campbellii infection

Journal of Fish Diseases — Sun, 07 Jun 2009 23:00:00 +0100

Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli. A definitive role for DnaK was then d...

Lymphocystis disease virus persists in the epidermal tissues of olive flounder, Paralichthys olivaceus (Temminch & Schlegel), at low temperatures

Journal of Fish Diseases — Sun, 07 Jun 2009 23:00:00 +0100

Olive flounder artificially infected with lymphocystis disease virus (LCDV) were reared at 10, 20 and 30 °C for 60 days, to compare LCD-incidence. In the fish reared at 20 °C, lymphocystis cells appeared on the skin and fins at 35 days post-challenge, and the cumulative LCD-incidence was 80% at 60 days. High levels of LCDV, with a mean polymerase chain reaction (PCR) titre of 106 PCR-U mg[minus]1 tissue, were detected in the fins and skin of LCD-affected fish at 20 °C, but were not detected in the spleen, kidney, brain and intestinal tissues of these fish. No LCD clinical signs were observed in the fish reared at 10 °C and 30 °C; however, a low level of LCDV (103 PCR-U mg[minus]1 tissue) was detected in the fins and skin of these fish. By increasing the rearing temperature from 10 to ...

Time-related changes of the intestinal morphology of Atlantic salmon, Salmo salar L., at two different soybean meal inclusion levels

Journal of Fish Diseases — Sun, 07 Jun 2009 23:00:00 +0100

Soybean meal (SBM) induces enteritis in the distal intestine of Atlantic salmon. The present study assesses the effects of SBM concentrations on the kinetics of the enteritis process. Fish of 300 g, kept at 12 °C, were fed diets with different SBM inclusions: 0%, 10% and 20% SBM for 57 days. Samples of the distal intestine of five fish per treatment were taken for histological and electron microscopical analysis. A semi-quantitative scoring system was used to assess the degree of the morphological changes induced by SBM feeding in the distal intestinal epithelium. The first signs of enteritis appeared earlier in the salmon fed the 20SBM diet than in those fed the 10SBM diet. Thereafter, the condition increased steadily, displaying no signs of recovery. Furthermore, at the lower concentrat...

Immunostimulants in prevention of columnaris disease of rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Thu, 04 Jun 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Development of a multiplex PCR assay for Photobacterium damselae subsp. piscicida identification in fish samples

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

A multiplex polymerase chain reaction protocol for the detection of Photobacterium damselae and subspecies piscicida and damselae discrimination, with internal amplification control, was developed. Assay specificity was assessed by testing 19 target and 25 non-target pure cultures. The detection limit was 500 fg, corresponding to 100 genome equivalents. The optimized protocol was also prevalidated with spleen, kidney and blood samples from infected and uninfected sea bass, without any culture step, and it can be proposed as a valid alternative to culture standard methods for the rapid and specific diagnosis of photobacteriosis in fish. (Source: Journal of Fish Diseases)

Tissue tropism of nervous necrosis virus (NNV) in Atlantic cod, Gadus morhua L., after intraperitoneal challenge with a virus isolate from diseased Atlantic halibut, Hippoglossus hippoglossus (L.)

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

Atlantic cod, Gadus morhua, averaging 100 g, were experimentally challenged by intraperitoneal injection of nervous necrosis virus (NNV) originating from Atlantic halibut. Cod tissues, including blood, gill, pectoral fin, barbel, ventricle, atrium, spleen, liver, lateral line (including muscle tissue), eye (retina) and brain, were sampled at day 25 and 130 and investigated by real-time RT-PCR for the presence of NNV. Relative quantifications at day 130 were calculated using the 2[minus][Delta][Delta]Ct method. Immunosuppression by injection of prednisolone-acetate was introduced for a 30-day period, and tissue sampled at day 180 and relative quantification estimated. No mortality or clinical signs of disease were observed in the challenged group. The challenge resulted in detection of NNV ...

Outbreak of betanodavirus infection in tilapia, Oreochromis niloticus (L.), in fresh water

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

A betanodavirus associated with a massive mortality was isolated from larvae of tilapia, Oreochromis niloticus, maintained in fresh water at 30 °C. Histopathology revealed vacuolation of the nervous system, suggesting an infection by a betanodavirus. The virus was identified by indirect fluorescent antibody test in the SSN1 cell line and further characterized by sequencing of a PCR product. Sequencing of the T4 region of the coat protein gene indicated a phylogenetic clustering of this isolate within the red-spotted grouper nervous necrosis virus type. However, the tilapia isolate formed a unique branch distinct from other betanodavirus isolates. The disease was experimentally reproduced by bath infection of young tilapia at 30 °C. The reservoir of virus at the origin of the outbreak rem...

The effect of hyperoxygenation and reduced flow in fresh water and subsequent infectious pancreatic necrosis virus challenge in sea water, on the intestinal barrier integrity in Atlantic salmon, Salmo salar L.

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

In high intensive fish production systems, hyperoxygenation and reduced flow are often used to save water and increase the holding capacity. This commonly used husbandry practice has been shown to be stressful to fish and increase mortality after infectious pancreatic necrosis virus (IPNV) challenge, but the cause and effect relationship is not known. Salmonids are particularly sensitive to stress during smoltification and the first weeks after seawater (SW) transfer. This work aimed at investigating the impact of hyperoxygenation combined with reduced flow in fresh water (FW), on the intestinal barrier in FW as well as during later life stages in SW. It further aims at investigating the role of the intestinal barrier during IPNV challenge and possible secondary infections. Hyperoxygenatio...

Homogeneity among Lactococcus garvieae isolates from striped jack, Pseudocaranx dentex (Bloch & Schneider), and its ectoparasites

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Distribution of the introduced cyprinid herpesvirus 3 in a wild population of common carp, Cyprinus carpio L.

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

Cyprinid herpesvirus 3 (CyHV-3), which causes a lethal disease in common carp, Cyprinus carpio L., and koi, C. carpio koi, first occurred in Lake Biwa, Japan in 2004. To elucidate distribution of CyHV-3 in a wild common carp population, we conducted a PCR survey of CyHV-3 among such fish in Lake Biwa in 2006. Only 6% (1/18) of the common carp smaller than 300 mm were positive with PCR, whereas 31% (18/58) of fish larger than 300 mm were positive. To evaluate their past exposure to CyHV-3 infection based on the presence of antibodies, we also measured the levels of serum anti-CyHV-3 antibodies in the carp, using an enzyme-linked immunosorbent assay. None (0/26) of the fish smaller than 300 mm was positive for the antibodies, whereas 54% (33/61) of fish larger than 300 mm were positive. Of t...

Development and evaluation of a loop-mediated isothermal amplification assay for rapid and simple detection of Flavobacterium psychrophilum

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout fry syndrome of salmonids. The pathogen has been reported from all regions in the world involved in salmonid aquaculture, but also from natural fresh-water environments. We established a quantitative loop-mediated isothermal amplification of DNA (LAMP) method to estimate quantities of F. psychrophilum. LAMP primers were designed based on the sequence of the DNA topoisomerase IV subunit B gene, parE, of F. psychrophilum. parE LAMP exhibited a high specificity for the parE gene of F. psychrophilum but not for other related species. parE LAMP detected the gene in a wide range of concentrations from 2.0 × 101 to 2.0 × 109 copies/reaction within 70 min and revealed a good correlation between ...

Susceptibility of selected freshwater fish species to a UK Lactococcus garvieae isolate

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

Gram-positive cocci recovered from diseased rainbow trout from a farm in England were characterized by different methods, including pulsed field gel electrophoresis, as virulent Lactococcus garvieae serogroup 2 (pulsotype A1). Groups of rainbow trout were kept at a range of temperatures and injected intraperitoneally (i.p.) with one of the UK isolates, L. garvieae 00021. The 18 °C and 16 °C groups showed 67% and 28% mortality, respectively, by day 27 post-injection. Fish kept at 14 °C or lower were less susceptible ([le]3% mortality). Raising the temperature of all groups to 18 °C at day 27 post-injection did not result in recurrence of the disease, even though viable bacteria were recovered from all groups 42 days later. Grayling were highly susceptible, with 65% mortalities when chal...

Tetrahymena sp. infection in guppies, Poecilia reticulata Peters: parasite characterization and pathology of infected fish

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

Tetrahymena sp. infection was diagnosed in guppies imported from Singapore. The parasite was isolated (Tet-NI) and optimally cultured in vitro in RM-9 medium. Cytological analyses [silver-staining and scanning electron microscopy (SEM)] revealed a pyriform-shaped, 64 × 41-[mu]m holotrich ciliate without caudal cilium, containing a macro-nucleus (18.25 × 16.83 [mu]m) and micro-nucleus (5.73 × 5.40 [mu]m). Wet-mount examination and histological analyses of fish exposed to the parasite by co-habitation, immersion and infection by i.p. (intra-peritoneal) and i.m. (intra-muscular) injection revealed numerous ciliates on the skin, and in the gill and caudal fin blood vessels. Ciliates surrounded internal organs, the peri-orbital region of the eye, and were observed inside developing guppy emb...

Lipopolysaccharide extraction: a phenol alternative

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Molecular detection of three shrimp viruses and genetic variation of white spot syndrome virus in Hainan Province, China, in 2007

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

White spot syndrome virus (WSSV), Taura syndrome virus (TSV) and infectious hypodermal and haematopoietic necrosis virus (IHHNV) have been responsible for major pandemics affecting the shrimp farming industry. Shrimp samples were collected from eight farms in Hainan Province, China, during 2007 and analysed by polymerase chain reaction (PCR) or reverse transcriptase PCR methods to determine the prevalence of these viruses. From the eight sampling locations, only samples from one farm did not show any indication of infection with WSSV, TSV or IHHNV, while samples from one additional farm exhibited evidence of infection with TSV only. Surprisingly, evidence of co-infection with TSV and IHHNV was found among samples at two farms while evidence of co-infection with all three viruses (WSSV, TSV...

Expression and characterization of the periplasmic cobalamin-binding protein of Photobacterium damselae subsp. piscicida

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

Cobalamin (vitamin B12) is an essential cofactor in a variety of enzymatic reactions and most prokaryotes contain transport systems to import vitamin B12. A gene coding for a periplasmic cobalamin-binding protein of Photobacterium damselae subsp. piscicida was identified by in silico analysis of sequences from a genomic library. The open reading frame was composed of 834 bp encoding a protein of 277 amino acids. The protein showed 61% identity with the vitamin B12-binding protein precursor of P. profundum, 53% identity with the corresponding protein of Vibrio parahaemolyticus and 43% identity with the periplasmic binding protein BtuF of Escherichia coli. The expression of the native protein was investigated in P. damselae subsp. piscicida, but BtuF was weakly expressed under normal conditi...

Eustrongylides ignotus infecting commercial bass, Morone chrysops female X Morone saxatilis male, and other fish in the southeastern USA

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

(Source: Journal of Fish Diseases)

Soybean meal alters autochthonous microbial populations, microvilli morphology and compromises intestinal enterocyte integrity of rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

Rainbow trout were fed either a diet containing fishmeal (FM) as the crude protein source or a diet containing 50% replacement with soybean meal (SBM) for 16 weeks. An enteritis-like effect was observed in the SBM group; villi, enterocytes and microvilli were noticeably damaged compared with the FM group. The posterior intestine microvilli of SBM-fed fish were significantly shorter and the anterior intestine microvilli significantly less dense than the FM-fed fish. Electron microscopy confirmed the presence of autochthonous bacterial populations associated with microvilli of both fish groups. Reduced density of microvilli consequently led to increased exposure of enterocyte tight junctions, which combined with necrotic enterocytes is likely to diminish the protective barrier of the intesti...

Neutralizing antibody levels for protection against betanodavirus infection in sevenband grouper, Epinephelus septemfasciatus (Thunberg), immunized with an inactivated virus vaccine

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

An inactivated betanodavirus, red-spotted grouper nervous necrosis virus (RGNNV), is a vaccine candidate for viral nervous necrosis (VNN). The present study was conducted to examine inoculation doses of the vaccine and neutralizing antibody titre levels to protect fish against VNN. Young sevenband grouper, Epinephelus septemfasciatus, averaging 25.4 g, were immunized at 25 °C water temperature by a single intraperitoneal injection of formalin-inactivated RGNNV. Fish immunized at vaccine doses of 108.5, 108.0, 107.5, 107.0 and 106.5 TCID50 per fish produced antibodies at mean titres of 1:907, 1:511, 1:259, 1:197 and 1:96, respectively, at 20 days post-immunization (p.i.). Neutralizing antibodies were not detected in any control fish (titre (Source: Journal of Fish Diseases)