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Background: There has been great progress in the use of endoscopic ultrasound (EUS)-guided drainage in acute pancreatitis patients using a novel lumen-apposing metal stent (LAMS) in the last decade, but some patients experience bleeding. Our research analyzed the preprocedural risk factors for bleeding. Methods: From July 13, 2016 to June 23, 2021, we retrospectively analyzed all patients who received endoscopic drainage by the LAMS in our hospital. Univariate and multivariate statistical analyses were used to identify the independent risk factors. We plotted ROC curves based on the independent risk factors. Results: A total of 205 patients were analyzed and 5 patients were excluded. A total of 200 patients were included in our research. Thirty (15%) patients presented with bleeding. In the multivariate analysis, computed tomography severity index score (CTSI) score [odds ratio (OR), 2.66; 95% CI: 1.31–5.38; P = 0.007], positive blood cultures [odds ratio (OR), 5.35; 95% CI: 1.31–21.9; P = 0.02], and Acute Physiology and Chronic Health Evaluation II (APACHE II) score [odds ratio (OR), 1.14; 95% CI: 1. 01–1.29; P = 0.045] were associated with bleeding. The area under the ROC curve of the combined predictive indicator was 0.79. Conclusion: Bleeding in endoscopic drainage by the LAMS is significantly associated with the CTSI score, positive blood cultures, and APACHE II score. This result could help clinicians make more appropriate choices. [ABSTRACT FROM AUTHOR]

Infectious pancreatic necrosis (IPN) was assessed according to the criteria of the Animal Health Law (AHL), in particular, the criteria of Article 7 on disease profile and impacts, Article 5 on its eligibility to be listed, Annex IV for its categorisation according to disease prevention and control rules as in Article 9, and Article 8 for listing animal species related to IPN. The assessment was performed following a methodology previously published. The outcome reported is the median of the probability ranges provided by the experts, which indicates whether each criterion is fulfilled (lower bound ≥ 66%) or not (upper bound ≤ 33%), or whether there is uncertainty about fulfilment. Reasoning points are reported for criteria with an uncertain outcome. According to the assessment here performed, it is uncertain whether IPN can be considered eligible to be listed for Union intervention according to Article 5 of the AHL (50–90% probability). According to the criteria in Annex IV, for the purpose of categorisation related to the level of prevention and control as in Article 9 of the AHL, the AHAW Panel concluded that IPN does not meet the criteria in Section 1 (Category A; 0–1% probability of meeting the criteria) and it is uncertain whether it meets the criteria in Sections 2, 3, 4 and 5 (Categories B, C, D and E; 33–66%, 33–66%, 50–90% and 50–99% probability of meeting the criteria, respectively). The animal species to be listed for IPN according to Article 8 criteria are provided. [ABSTRACT FROM AUTHOR]

Abstract Infectious pancreatic necrosis (IPN) was assessed according to the criteria of the Animal Health Law (AHL), in particular, the criteria of Article 7 on disease profile and impacts, Article 5 on its eligibility to be listed, Annex IV for its categorisation according to disease prevention and control rules as in Article 9, and Article 8 for listing animal species related to IPN. The assessment was performed following a methodology previously published. The outcome reported is the median of the probability ranges provided by the experts, which indicates whether each criterion is fulfilled (lower bound ≥ 66%) or not (upper bound ≤ 33%), or whether there is uncertainty about fulfilment. Reasoning points are reported for criteria with an uncertain outcome. According to the assessment here performed, it is uncertain whether IPN can be considered eligible to be listed for Union intervention according to Article 5 of the AHL (50–90% probability). According to the criteria in Annex IV, for the purpose of categorisation related to the level of prevention and control as in Article 9 of the AHL, the AHAW Panel concluded that IPN does not meet the criteria in Section 1 (Category A; 0–1% probability of meeting the criteria) and it is uncertain whether it meets the criteria in Sections 2, 3, 4 and 5 (Categories B, C, D and E; 33–66%, 33–66%, 50–90% and 50–99% probability of meeting the criteria, respectively). The animal species to be listed for IPN according to Article 8 criteria are provided.

Nannochloropsis oceanica is a unicellular oleaginous microalga of emerging biotechnological interest with a sequenced, annotated genome, available transcriptomic and proteomic data, and well-established basic molecular tools for genetic engineering. To establish N. oceanica as a eukaryotic host for recombinant protein synthesis and develop molecular technology for vaccine production, we chose the viral surface protein 2 (VP2) of a pathogenic fish virus that causes infectious pancreatic necrosis as a model vaccine. Upon stable nuclear transformation of N. oceanica strain CCMP1779 with the codon-optimized VP2 gene, a Venus reporter fusion served to evaluate the strength of different endogenous promoters in transformant populations by qPCR and flow cytometry. The highest VP2 yields were achieved for the elongation factor promoter, with enhancer effects by its N-terminal leader sequence. Individual transformants differed in their production capability of reporter-free VP2 by orders of magnitude. When subjecting the best candidates to kinetic analyses of growth and VP2 production in photobioreactors, recombinant protein integrity was maintained until the early stationary growth phase, and a high yield of 4.4% VP2 of total soluble protein was achieved. The maximum yield correlated with multiple integrations of the expression vector into the nuclear genome. The results demonstrate that N. oceanica was successfully engineered to constitute a robust platform for high-level production of a model subunit vaccine. The molecular methodology established here can likely be adapted in a straightforward manner to the production of further vaccines in the same host, allowing their distribution to fish, vertebrates, or humans via a microalgae-containing diet. Key points: • We engineered N. oceanica for recombinant protein production. • The antigenic surface protein 2 of IPN virus could indeed be expressed in the host. • A high yield of 4.4% VP2 of total soluble protein was achieved in N. oceanica. [ABSTRACT FROM AUTHOR]

One of the fastest growing branches of the national livestock breeding in Bulgaria is aquaculture production. The development of aquaculture production is directly related to the health of the cultivated fish and indirectly to the health of the wild fauna. Economically, breeding can be severely complicated by the appearance of infections especially those ones with viral etiology. The most serious problem for Bulgarian trout producers over the last decade is Infectious pancreatic necrosis (IPN) which is a highly contagious viral disease of young salmonid fish. It is caused by a virus (IPNV) that belongs to the family Birnaviridae. The IPNV has been isolated from many geographic regions around the world with different environments and a variety of aquatic animals. In Bulgaria, the IPNV was confirmed 13 years ago. There are several cases with heavy mortality rates every year. Thus, the aim of this review was to extend knowledge of IPN, and to present methods of its control.

Objective To explore the potential relationship between early inflammatory response and late infectious pancreatic necrosis (IPN) in patients with acute pancreatitis (AP). Methods Retrospectively included the moderately severe acute pancreas admitted to the Affiliated Hospital of Southwest Medical University from June 2019 to June 2020 219 cases of MSAP patients and 53 cases of severe acute pancreatitis (SAP) were divided into SIRS group and 112 non-SRIS groups according to whether they were combined with systemic inflammatory response syndrome (SIRS) at the initial stage of the disease., Serological indicators, complications, and mortality. Measurement data were compared between the two groups by t test or Mann-Whitney U test; count data between groups were compared by χ2 test, and further pairwise comparisons between multiple groups were performed by Bon-ferroni method. Regression analysis screens valuable variables, receiver operating characteristic curve (ROC curve) is used to compare the diagnostic value of variables, and the area under the ROC curve (AUC) is compared by Z test. Results WBC, CRP, and CRP of patients in the SIRS group Higher procalcitonin (all P values ​​<0.05), SIRS combination and acute peripancreatic necrosis accumulation (ANC), IPN, pancreatic necrosis (PN), organ dysfunction (OF), multiple organ dysfunction (MODS), The proportions of severe acute pancreatitis (SAP), critical acute pancreatitis (CAP), death, BISAP score>2, CTSI score>2, and RANSON score>2 were all higher than those of the non-SIRS group (all P values ​​<0.05). Factor analysis showed that the duration of SIRS, obesity, CRP, WBC, blood urea nitrogen, PN, ANC, SAP, MODS, RANSON score, BISAP score, and CTSI score were all influencing factors for the occurrence of IPN in AP patients (all P values ​​<0.05) ; Multivariate analysis showed that the duration of SIRS (OR=1.307, 95%CI: 1.081～1.580, P=0.006), ANC (OR=42.247, 95%CI: 10.829～164.818, P<0.001) were risk factors for IPN When ANC was excluded, SIRS duration (OR=1.430, 95%CI: 1.207～1.694, P<0.001), PN (OR=5.296, 95%CI: 1.845～15.203, P=0.002) were risk factors for IPN. The ROC curve of predicted IPN shows:SIRS duration (AUC=0.772, Youden index: 0.521), RANSON score (AUC=0.701, Youden index: 0.319), BISAP score (AUC=0.741, Youden index: 0.377), CTSI score (AUC=0.765, There was no statistically significant difference in the AUC of the Youden index: 0.414) (all P values> 0.05). The proportions of PN, ANC, IPN, SAP, and CAP in the ultra-long-term SIRS group (>4 d) were significant. Higher than the non-SIRS group (0), the transient SIRS group (1 to 2 d), and the persistent SIRS group (3 to 4 d) (all P values ​​<0.05), the proportion of patients in the persistent SIRS group was higher than that of no SIRS group (P<0.05). Conclusion AP patients are more likely to have organ failure and local complications when SIRS is combined in the early stage. When the duration of SIRS is> 4.5 d, the risk of IPN in patients is significantly increased. [ABSTRACT FROM AUTHOR]

One of the fastest growing branches of the national livestock breeding in Bulgaria is aquaculture production. The development of aquaculture production is directly related to the health of the cultivated fish and indirectly to the health of the wild fauna. Economically, breeding can be severely complicated by the appearance of infections especially those ones with viral etiology. The most serious problem for Bulgarian trout producers over the last decade is Infectious pancreatic necrosis (IPN) which is a highly contagious viral disease of young salmonid fish. It is caused by a virus (IPNV) that belongs to the family Birnaviridae. The IPNV has been isolated from many geographic regions around the world with different environments and a variety of aquatic animals. In Bulgaria, the IPNV was confirmed 13 years ago. There are several cases with heavy mortality rates every year. Thus, the aim of this review was to extend knowledge of IPN, and to present methods of its control. [ABSTRACT FROM AUTHOR]

The population of brown trout (Salmo trutta fario) in continental Europe is on the decline, with infectious diseases confirmed as one of the causative factors. However, no data on the epizootiological situation of wild fish in the Czech Republic are currently available. In this study, brown trout (n = 260) from eight rivers were examined for the presence of viral and parasitical pathogens. Salmonid alphavirus-2, infectious pancreatic necrosis virus, piscine novirhabdovirus (VHSV) and salmonid novirhabdovirus (IHNV) were not detected using PCR. Cell culturing showed no viruses as well, and serological analysis of 110 sera did not detect any specific antibodies against VHSV or IHNV. Fish from two rivers were positive for the presence of piscine orthoreovirus-3 (PRV-3), subtype PRV-3b. However, none of the PRV-3-positive fish showed gross pathologies typically associated with PRV infections. By far the most widespread pathogen was Tetracapsuloides bryosalmonae which was confirmed in each of the examined locations, with a prevalence of up to 65% and 100%, as established by immunohistochemistry and PCR, respectively. Furthermore, up to 43.8% of fish showed signs of proliferative kidney disease caused by T. bryosalmonae, suggesting that this parasite is a main health challenge for brown trout in the Czech Republic.

Vaccination is an important strategy for the control and prevention of infectious pancreatic necrosis (IPN) in farmed Atlantic salmon (Salmo salar) in the post-smolt stage in sea-water. In this study, a heterologous gene expression system, based on a replicon construct of salmonid alphavirus (SAV), was used for in vitro and in vivo expression of IPN virus proteins. The large open reading frame of segment A, encoding the polyprotein NH2-pVP2-VP4-VP3-COOH, as well as pVP2, were cloned and expressed by the SAV replicon in Chinook salmon embryo cells (CHSE-214) and epithelioma papulosum cyprini (EPC) cells. The replicon constructs pSAV/polyprotein (pSAV/PP) and pSAV/pVP2 were used to immunize Atlantic salmon (Salmo salar) by a single intramuscular injection and tested in a subsequent IPN virus (IPNV) challenge trial. A low to moderate protection against IPN was observed in fish immunized with the replicon vaccine that encoded the pSAV/PP, while the pSAV/pVP2 construct was not found to induce protection.

Abstract: Infectious pancreatic necrosis (IPN) is an important restraint to production of salmonids in aquaculture globally. In order to implement efficacious mitigation strategies for control of this disease, it is important to understand infection routes under current production systems. IPN virus has been shown to be transmitted vertically in Rainbow trout, from broodstock to fingerlings in hatcheries, and there is circumstantial evidence suggesting that vertical transmission can also occur in Atlantic salmon, in addition to horizontal transmission between grow‐out fish in farms. In this study, we show that the smolt carries infection with IPN from hatchery to the marine farm. We do this by comparing sequences from fish groups taken both in hatcheries and on corresponding marine grow‐out farms. We use statistical analysis to prove that sequences obtained from the same fish group in both hatchery and marine farm are more similar than sequences obtained from random fish groups on hatcheries and marine farms. [ABSTRACT FROM AUTHOR]

A semi-quantitative model for risk ranking of aquaculture facilities in Switzerland with regard to the introduction and spread of Viral Haemorrhagic Septicaemia (VHS) and Infectious Haematopoietic Necrosis (IHN) was developed in a previous study (Diserens et al., 2013). The objective of the present study was to validate this model using data collected during field visits on aquaculture sites in four Swiss cantons compared to data collected through a questionnaire in the previous study. A discrepancy between the values obtained with the two different methods was found in 32.8% of the parameters, resulting in a significant difference (p < 0.001) in the risk classification of the facilities. As data gathered exclusively by means of a questionnaire are not of sufficient quality to perform a risk-based surveillance of aquaculture facilities a combination of questionnaires and farm inspections is proposed. A web-based reporting system could be advantageous for the factors which were identified as being more likely to vary over time, in particular for factors considering fish movements, which showed a marginally significant difference in their risk scores (p ≥ 0.1) within a six- month period. Nevertheless, the model proved to be stable over the considered period of time as no substantial fluctuations in the risk categorisation were observed (Kappa agreement of 0.77).Finally, the model proved to be suitable to deliver a reliable risk ranking of Swiss aquaculture facilities according to their risk of getting infected with or spreading of VHS and IHN, as the five facilities that tested positive for these diseases in the last ten years were ranked as medium or high risk. Moreover, because the seven fish farms that were infected with Infectious Pancreatic Necrosis (IPN) during the same period also belonged to the risk categories medium and high, the classification appeared to correlate with the occurrence of this third viral fish disease. [ABSTRACT FROM AUTHOR]

Infectious pancreatic necrosis virus (IPNV) is a member of the Aquabirnavirus genus, which caused mass mortality (nearly 100%) in farmed rainbow trout ( Oncorhynchus mykiss ) in aquaculture farms in 2016, China. Major clinical signs included decreased appetite, mucous-like stools, and darkened pigmentation. Pathological changes in moribund fish were observed, such as marked vacuolar degeneration of the pancreatic cells with pyknotic nucleus and decreased zymogen granules, severe hemorrhage in the liver, and tumidness of respiratory epithelium in gills. In addition, the tissue fluid of diseased fish could produce a cytopathic effect (CPE) in RTG-2 cells. The presence of specific 206 bp fragments by the reverse transcription-polymerase chain reaction (RT-PCR) using tissue homogenate of diseased fish and supernatant of infected cells revealed that IPNV could be confirmed. The pathogenicity test of cell culture supernatant detected cumulative mortality of 80%, and the clinical symptoms observed in the moribund and dead fish were similar to the naturally infected fish. Furthermore, the sequence analysis of VP2 gene showed that the isolated virus strain belonged to genogroup 1, and 97% homology with the Mexican IPNV isolate was found. To our knowledge, this is the first report on IPNV natural infection in the southwest of China. [ABSTRACT FROM AUTHOR]

Background: Infectious Pancreatic Necrosis (IPN) is a highly contagious birnavirus disease of farmed salmonid fish, which often causes high levels of morbidity and mortality. A large host genetic component to resistance has been previously described for Atlantic salmon (Salmo salar L.), which mediates high mortality rates in some families and zero mortality in others. However, the molecular and immunological basis for this resistance is not yet fully known. This manuscript describes a global comparison of the gene expression profiles of resistant and susceptible Atlantic salmon fry following challenge with the IPN virus. Results: Salmon fry from two IPNV-resistant and two IPNV-susceptible full sibling families were challenged with the virus and sampled at 1 day, 7 days and 20 days post-challenge. Significant viral titre was observed in both resistant and susceptible fish at all timepoints, although generally at higher levels in susceptible fish. Gene expression profiles combined with gene ontology and pathway analyses demonstrated that while a clear immune response was observed in both resistant and susceptible fish, there were striking differences between the two phenotypes. The susceptible fish showed marked up-regulation of genes related to cytokine activity and inflammatory response that evidently failed to protect against the virus. In contrast, the resistant fish demonstrated a less pronounced immune response including up-regulation of genes relating to the M2 macrophage system. Conclusions: While only the susceptible phenotype shows appreciable mortality levels, both resistant and susceptible fish can become infected with IPNV. Susceptible fish are characterized by a much larger, yet ineffective, immune response, largely related to cytokine and inflammatory systems. Resistant fish demonstrate a more moderate, putative macrophage-mediated inflammatory response, which may contribute to their survival. [ABSTRACT FROM AUTHOR]

Vaccination is an important strategy for the control and prevention of infectious pancreatic necrosis (IPN) in farmed Atlantic salmon (Salmo salar) in the post-smolt stage in sea-water. In this study, a heterologous gene expression system, based on a replicon construct of salmonid alphavirus (SAV), was used for in vitro and in vivo expression of IPN virus proteins. The large open reading frame of segment A, encoding the polyprotein NH2-pVP2-VP4-VP3-COOH, as well as pVP2, were cloned and expressed by the SAV replicon in Chinook salmon embryo cells (CHSE-214) and epithelioma papulosum cyprini (EPC) cells. The replicon constructs pSAV/polyprotein (pSAV/PP) and pSAV/pVP2 were used to immunize Atlantic salmon (Salmo salar) by a single intramuscular injection and tested in a subsequent IPN virus (IPNV) challenge trial. A low to moderate protection against IPN was observed in fish immunized with the replicon vaccine that encoded the pSAV/PP, while the pSAV/pVP2 construct was not found to induce protection. [ABSTRACT FROM AUTHOR]

Objective: Acute pancreatitis (AP) is a self-limiting disease. However, 20-30% of patients will develop into severe AP (SAP), and infectious pancreatic necrosis in the late course of SAP is the leading cause of death for such patients. This review aims to provide a comprehensive and systematic report of the currently published risk factors for complicated infectious pancreatic necrosis in patients with severe acute pancreatitis by meta-analysis of published retrospective case-control studies., Methods: Five electronic database systems were selected to search for articles on risk factors of infectious pancreatic necrosis in patients with severe acute pancreatitis. According to the heterogeneity among studies, the standardized mean difference (SMD), odds ratio and 95% confidence interval (95%CI) were calculated by applying a random-effects model or fixed-effects model, respectively., Results: As of 2nd Jun, 2021, a total of 1408 articles were searched, but only 21 articles were finally included in this meta-analysis. The results found that patients with severe acute pancreatitis complicated by infected pancreatic necrosis had higher APACHE II scores and higher levels of lipase (LPS), C-reactive protein (CRP) and procalcitonin (PCT) compared to patients with severe acute pancreatitis alone. The differences were statistically significant (APACHE II: SMD = 0.86, 95%CI: 0.55, 1.18; LPS: SMD = 1.52, 95%CI: 1.13, 1.92; CRP: SMD = 1.42, 95%CI: 1.05, 1.79; PCT: SMD = 1.82, 95%CI: 1.36, 2.28)., Conclusions: Compared with patients with severe acute pancreatitis alone, high levels of LPS, CRP, PCT and high APACHE II score were risk factors for infectious pancreatic necrosis in patients with severe acute pancreatitis., Competing Interests: Declaration of Competing Interest All the authors declare that they have no conflict of interest., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Background: Restriction site-associated DNA sequencing (RAD-Seq) is a genome complexity reduction technique that facilitates large-scale marker discovery and genotyping by sequencing. Recent applications of RAD-Seq have included linkage and QTL mapping with a particular focus on non-model species. In the current study, we have applied RAD-Seq to two Atlantic salmon families from a commercial breeding program. The offspring from these families were classified into resistant or susceptible based on survival/mortality in an Infectious Pancreatic Necrosis (IPN) challenge experiment, and putative homozygous resistant or susceptible genotype at a major IPN-resistance QTL. From each family, the genomic DNA of the two heterozygous parents and seven offspring of each IPN phenotype and genotype was digested with the SbfI enzyme and sequenced in multiplexed pools. Results: Sequence was obtained from approximately 70,000 RAD loci in both families and a filtered set of 6,712 segregating SNPs were identified. Analyses of genome-wide RAD marker segregation patterns in the two families suggested SNP discovery on all 29 Atlantic salmon chromosome pairs, and highlighted the dearth of male recombination. The use of pedigreed samples allowed us to distinguish segregating SNPs from putative paralogous sequence variants resulting from the relatively recent genome duplication of salmonid species. Of the segregating SNPs, 50 were linked to the QTL. A subset of these QTL-linked SNPs were converted to a high-throughput assay and genotyped across large commercial populations of IPNV-challenged salmon fry. Several SNPs showed highly significant linkage and association with resistance to IPN, and population linkage-disequilibrium-based SNP tests for resistance were identified. Conclusions: We used RAD-Seq to successfully identify and characterise high-density genetic markers in pedigreed aquaculture Atlantic salmon. These results underline the effectiveness of RAD-Seq as a tool for rapid and efficient generation of QTL-targeted and genome-wide marker data in a large complex genome, and its possible utility in farmed animal selection programs. [ABSTRACT FROM AUTHOR]

During October 2009, a suspected outbreak of infectious pancreatic necrosis, with typical signs and high mortality, was observed in cultured rainbow trout (Oncorhynchus mykiss) fry (mean weight of 9 g) in a recirculating system in Fars Province, Iran. Tissue samples, including pyloric caeca as well as pancreatic tissues, liver, kidney, and spleen, were aseptically collected from 20 affected moribund fish for histopathological and molecular assays. Histopathologically, the exocrine pancreatic acinar cells exhibited the most notable pathology, including focal to extensive degeneration and coagulative necrosis with mononuclear inflammatory infiltrates. To confirm the diagnosis of clinical infectious pancreatic necrosis (IPN), a reverse transcription-polymerase chain reaction (RT-PCR) and sequence analysis were used. A 224-bp fragment of the IPN virus NS/VP3 (segment A) gene was amplified using cDNA prepared from infected pooled tissues of pancreas, liver, kidney, and spleen. The nucleotide sequence was most closely identified with the Sp serotype. [ABSTRACT FROM AUTHOR]

Histological changes associated with infectious pancreatic necrosis virus (IPNV) infection have historically been described for the pancreas and gut, but any involvement of the liver was poorly acknowledged or described. The aims of this study were to find robust evidence that the reported increase in liver pathology in Atlantic salmon post-smolts in natural outbreaks was effectively related to IPNV infection and retrospectively to report when such a shift in the involvement of the liver had taken place, supported by a histopathological description for a differential diagnosis. The study reports new findings concerning the dynamics of liver pathology development, with apoptosis, demonstrated by histological and immunological techniques, described as the most relevant and particular feature. Immunohistochemical examination of affected liver suggests apoptosis is not only the result of the virus infection itself but triggered through the action of the host’s innate immune response. Liver involvement contributes to the nature of infection and becomes an important factor in the disease process. Additionally, it was established that the increase in infectious pancreatic necrosis prevalence is correlated with a new distinct pattern of outbreak distribution throughout the year. The role of smolt category (i.e. S1, S1/2 or S0), hence timing of seawater transfer as a strong correlating factor, is discussed. [ABSTRACT FROM AUTHOR]

A fluorescent in situ hybridization (FISH) method was developed for detection of infectious pancreatic necrosis virus (IPNV) in paraffin-embedded tissues of Atlantic salmon, Salmo salar L. Several methods of probe labelling and detection were evaluated and found unsuitable for FISH because of tissue autofluorescence. Likewise, the use of avidin to detect biotin-labelled probe was obviated by the presence of endogenous biotin. An existing approach, using digoxigenin (DIG)-labelled probes and detection by anti-DIG antibody-labelled with alkaline phosphatase, was modified to use a fluorescent substrate, 2-hydroxy-3-naphthoic acid-2′-phenylanilide phosphate/4-chloro-2-methylbenzene diazonium hemi-zinc chloride salt (HNPP/Fast Red TR). This improved method allowed sensitive detection of IPNV target, without interference from autofluorescence or endogenous alkaline phosphatase. Furthermore, the reporter produces a discrete, non-fading signal, which is particularly suitable for analysis by confocal microscopy. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to estimate genetic parameters for resistance to infectious pancreatic necrosis (IPN) in Atlantic salmon and to evaluate the correlation between survival in challenge tests and survival in field outbreaks of IPN. The analyses were based on challenge test data from four sub-populations of fish. Challenge testing for resistance to IPN has been a part of Aqua Gen''s breeding programme since 1997. Data from 8 years was included in the study, and a total of 271,366 fish were tested. Moreover, data from two field outbreaks were analysed. The heritabilities were found to be in the range 0.17–0.45 for each year analysed separately. All years analysed together gave an overall estimate of the heritability of 0.31. The genetic correlations between IPN challenge tests and IPN field outbreaks were found to be in the range 0.78–0.83. The results confirm that there is genetic variation for resistance against IPN in Atlantic salmon, and that a strong positive genetic correlation between IPN challenge tests and IPN field outbreaks exists. [Copyright &y& Elsevier]

A total of 77 124 Atlantic salmon post-smolts, representing 197 full-sib families produced by 149 males and 197 females, experienced a field challenge from infectious pancreatic necrosis virus (IPNV), following transfer to three separate seawater sites. The first IPN mortality was observed 45 days after transfer, and the duration of the epidemic varied between 37 and 92 days among sites. Mortalities were traced to their parental families by PIT (Passive Integrated Transpondes) tag records and DNA genotyping. Full-sib family mean incidence of mortality was calculated for each family on each site. Heritabilities were estimated based on the heterogeneity of chi-square using incidence within half-sib families and the variance in incidence among full-sib families, both on the observed and underlying liability scale. The observed correlation among families across sites was used to estimate genetic correlations. The overall mortality rate was 10.8%, with only small differences between sites, ranging from 10.3% to 11.9%. Heritabilities on the liability scale were found to be moderate to strong, and ranged between 0.24 and 0.81, with a pooled estimate of 0.43, greater than is typically associated with disease traits. Genetic correlations among sites were all substantial, between 0.71 and 0.78, and indicated that a substantial component of the genetic variation displayed within sites was common to all. The results show that field challenges can yield very good genetic information on family differences in resistance, especially when replicated over sites, which may then be developed for use in selection for breeding strains of Atlantic salmon with greater resistance to IPN. [ABSTRACT FROM AUTHOR]

Infectious pancreatic necrosis (IPN) is an important viral disease of salmonids. In the rainbow trout (Oncorhynchus mykiss) an etiological agent, a birnavirus causes a lethal disease in fry and fingerling. Survivors act as asymptomatic carriers at other life stages, which may shed the etiologic agent, or transmit it vertically to their progeny. Diagnosis of IPN-diseased and detection of infected trouts are important for controlling the spread of the virus. The IPN is worldwide distributed, being recently identified in Mexico. In the present paper the epizootiology, prevention and control of this disease are reviewed in an exhaustive and systematical manner. [ABSTRACT FROM AUTHOR]

A clinical and histopathological review was carried out of 21 outbreaks of acute infectious pancreatic necrosis (IPN) in Scottish Atlantic salmon, Salmo salar L., farms (13 marine and eight fresh water) during 1991–2004. A distinctive syndrome was evident in both post-smolts in sea water and fry in fresh water, where liver lesions, which had not previously been associated with IPN, became a consistent finding in addition to the more typical pancreatic and intestinal changes. Initial cases were described in post-smolts in Shetland, but by the end of the period of investigation this type of pathology had extended down the West coast of Scotland and into Ireland. Limited viral strain analysis suggested that similar strains were involved in both fresh water and sea water and that these differed from earlier isolates from rainbow trout, Oncorhynchus mykiss (Walbaum). In fresh water, recovered fish frequently developed a greatly distended intestine associated with accumulation of undigested food. In sea water, after the initial, often significant (50% or more), losses, there were many fish which failed to grow and became chronically emaciated and prone to sea louse infection. Although use of transfer diets containing immune enhancers and the selection of IPN resistant broodstock has reduced losses the disease remains a serious cause of economic loss. [ABSTRACT FROM AUTHOR]

Abstract: 2270 Atlantic salmon smolts representing 30 mostly full-sibling families were transferred to a sea cage in central Norway in May 2003. In the period between transfer to sea and termination of the experiment in August 2003, 42.2% of these fish died, mostly as a result of an outbreak of IPN virus. 1198 of the survivors were investigated in their abundance of the sea lice Lepeophtheirus salmonis and Caligus elongatus. In total, 6000 L. salmonis and 238 C. elongatus were recovered from the fish, giving an average combined lice abundance of 5.2 and a range from 0 to 25 lice per fish. Significant differences in abundance of L. salmonis were observed among the families (P&#60;0.0001), with mean family values ranging from 3.84 to 6.51. This equates to a 70% variation in infection between the lowest and highest infected families, and gave a “heritability” of 0.074 (±0.022). Inter-family differences in abundance of C. elongatus ranged from 0.09 to 0.37; however, these differences were not significant (P=0.67). A significant positive correlation between family sample size, reflecting to some degree family susceptibility to IPN virus, and mean family weight was observed (R 2=0.61, P&#60;0.0001); however, no correlation between mean family sample size and family abundance of L. salmonis (R 2=0.04, P=0.29), or family abundance of C. elongatus (R 2=0.11, P=0.08) were observed. No relationship between individual fish size measured as length or weight, and intensity of L. salmonis infection was observed in the pooled material, within each family or between families using mean family values. [Copyright &y& Elsevier]

Infectious pancreatic necrosis virus (IPNV) induces an economically important disease that causes a pancreatic and gut-associated pathology in freshwater fish. Currently IPN is also recognised as an emerging problem for sea water cultured salmonids. This study reports clinical IPN outbreaks in farmed Atlantic salmon, Salmo salar, in Scottish marine waters among S1 and S1/2 stock, as determined by light microscopy from 1990 to 2002. The IPN diagnosis by light microscopy was supported by isolation of the causative virus in cell culture. Prevalence was calculated from the number of positive IPN cases relative to the total number of marine reared salmon examined histologically each year. Data for Scotland indicate an overall increasing trend, but with prevalence changes between years. The prevalence of IPN in post-smolt Atlantic salmon in Scotland has increased from 1.2% in 1990 to 12.5% to date. In the Shetland Isles, IPN prevalence has increased from 1995 to 1996. Prevalence of IPN for areas of Scotland other than the Shetland Isles shows little change up to 2000, but with an increasing trend thereafter. IPN mortality and histological evidence of infection was first recorded in S1/2 salmon in 1996. IPN was recorded among S1 post-smolts during the spring months several weeks after transfer to sea. Outbreaks of IPN reached a peak in July following spring seawater transfer, and clinical was IPN uncommon after October. Mortality at sites with confirmed IPN varied between 0.03% and 0.1% per day in May and 0.5% per day in July, and then declined to early spring levels. IPN in both S1 and S1/2 fish groups showed affected acinar cells with acute necrosis and pyknosis with basophilic inclusions. IPN pathology extended into the gut mucosa and necrotic areas replaced with fibrous/fatty tissue and cell sloughing in combination with increased mucous resulting in an acute, catarrhal gut exudate. Salmon pancreas disease (SPD) was diagnosed by light microscopy in 1990 with a prevalence of 11.6%, declining to zero by 2002. [Copyright &y& Elsevier]

Abstract Two laboratory studies compared the effect of fish density and number of infectious fish on characteristics of survival of rainbow trout fry during controlled epidemics of infectious pancreatic necrosis (IPN). Analyses of hazard functions and survivor functions were used to determine whether peak death rate, time at which the peak death rate occurred and probability of survival to the end of the experiment were associated with fish density and number of infectious fish added (i.e. pathogen concentration). When number of infectious fish was low and fish density increased, the peak death rate increased, time of the peak death rate decreased and the probability of survival to the end of the experiment decreased. When number of infectious fish was high, the effect of density diminished. Loglogistic regression of survival data revealed that fish density, number of infectious fish and interaction between these two variables significantly affected time to death from IPN (P < 0.01). [ABSTRACT FROM AUTHOR]