Norwegian Veterinary Centre for Contract Research and Commercial Services

We suggest that during severe acute pancreatitis (SAP) with intra-abdominal hypertension, practitioners should consider decompressive laparotomy, even with intra-abdominal pressure (IAP) below 25 mmHg. Indeed, in this setting, non-occlusive mesenteric ischemia (NOMI) may occur even with IAP below this cutoff and lead to transmural necrosis if abdominal perfusion pressure is not promptly restored. We report our experience of 18 critically ill patients with SAP having undergone decompressive laparotomy of which one third had NOMI while IAP was mostly below 25 mmHg.

Cardiomyopathy syndrome (CMS) is a severe cardiac disease occurring in the grow-out sea phase of farmed Atlantic salmon with approximately 100 outbreaks annually in Norway. Piscine myocarditis virus (PMCV) is believed to be the causative agent of CMS. There is no vaccine available to control CMS, partially because PMCV withstands propagation in known cell cultures. In the present study, we selected the putative capsid protein of PMCV as the candidate antigen for immunization experiments and produced it in the plant Nicotiana benthamiana by transient expression. The recombinant PMCV antigen formed virus-like particles (VLPs). To evaluate the efficacy of the plant made VLP vaccine, a PMCV infection model was established. In an experimental salmon vaccination trial, the VLP vaccine triggered innate immunity, and indicative but not significant inhibition of viral replication in heart, spleen and kidney tissues was observed. Similarly, a reduction of inflammatory lesions in cardiomyocytes and subendocardial infiltration by mononuclear leukocytes were observed. Therefore, there was no difference in efficacy or immune response observed post the plant made PMCV VLP antigen vaccination.Taken together, this study has demonstrated that plant made VLP antigens should be investigated further as a possible platform for the development of PMCV antigens for a CMS vaccine.

Docetaxel, cisplatin, and 5‐fluorouracil (DCF) significantly improved overall survival in metastatic gastroesophageal adenocarcinoma (GEA). The aim of this study was to assess efficacy of DCF regimen as perioperative chemotherapy compared with surgery alone in patients with resectable GEA. We identified 789 patients who underwent surgery alone and 62 patients who received at least one cycle of DCF regimen consisting of docetaxel (75 mg/m2 on day 1), cisplatin (75 mg/m2 on day 1), and 5‐fluorouracil (750 mg/m2/day on continuous perfusion on days 1 to 5), every 3 weeks. Overall survival was compared using Cox proportional hazards regression model with adjustments for confounding factors provided by two propensity score methods: inverse probability of treatment weighting (IPTW) and matched‐pair analysis. In Cox multivariate analysis weighted by IPTW, DCF group was associated with favorable overall survival (OS) compared with the surgery group (HR = 0.59; 95% CI, 0.45–0.78; P = 0.0003). For the matched‐pair analysis (comparing 41 patients for each group with the same baseline characteristics), median OS was 22 months and 57 months for the surgery group and DCF group, respectively (log‐rank P = 0.0011). In Cox multivariate analysis, DCF group was associated with favorable OS compared with the surgery group (HR = 0.29; 95% IC, 0.14–0.64; P = 0.0019). In the matched‐pair population, major complications (Dindo‐Clavien grade 3–5) arose in six patients (14.63%) in the DCF group and seven patients (17.07%) in the surgery group (P = 1). Perioperative DCF chemotherapy is superior to surgery alone in terms of OS. A randomized phase III trial should compare DCF to standard perioperative regimens.

Pancreas disease (PD) caused by salmonid alphavirus (SAV) has a significant negative economic impact in the salmonid fish farming industry in northern Europe. Until recently, only SAV subtype 3 was present in Norwegian fish farms. However, in 2011, a marine SAV 2 subtype was detected in a fish farm outside the PD-endemic zone. This subtype has spread rapidly among fish farms in mid-Norway. The PD mortality in several farms has been lower than expected, although high mortality has also been reported. In this situation, the industry and the authorities needed scientific-based information about the virulence of the marine SAV 2 strain in Norway to decide how to handle this new situation. Atlantic salmon post-smolts were experimentally infected with SAV 2 and SAV 3 strains from six different PD cases in Norway. SAV 3-infected fish showed higher mortality than SAV 2-infected fish. Among the SAV 3 isolates, two isolates gave higher mortality than the third one. At the end of the experiment, fish in all SAV-infected groups had significantly lower weight than the uninfected control fish. This is the first published paper on PD to document that waterborne infection produced significantly higher mortality than intraperitoneal injection.

Salmonid alphavirus is the aetological agent of pancreas disease (PD) in marine Atlantic salmon, Salmo salar, and rainbow trout, Oncorhynchus mykiss, with most outbreaks in Norway caused by SAV subtype 3 (SAV3). This atypical alphavirus is transmitted horizontally causing a significant economic impact on the aquaculture industry. This histopathological and proteomic study, using an established cohabitational experimental model, investigated the correlation between tissue damage during PD and a number of serum proteins associated with these pathologies in Atlantic salmon. The proteins were identified by two-dimensional electrophoresis, trypsin digest and peptide MS/MS fingerprinting. A number of humoral components of immunity which may act as biomarkers of the disease were also identified. For example, creatine kinase, enolase and malate dehydrogenase serum concentrations were shown to correlate with pathology during PD. In contrast, hemopexin, transferrin, and apolipoprotein, amongst others, altered during later stages of the disease and did not correlate with tissue pathologies. This approach has given new insight into not only PD but also fish disease as a whole, by characterisation of the protein response to infection, through pathological processes to tissue recovery.Biological significanceSalmonid alphavirus causes pancreas disease (PD) in Atlantic salmon, Salmo salar, and has a major economic impact on the aquaculture industry. A proteomic investigation of the change to the serum proteome during PD has been made with an established experimental model of the disease. Serum proteins were identified by two-dimensional electrophoresis, trypsin digest and peptide MS/MS fingerprinting with 72 protein spots being shown to alter significantly over the 12 week period of the infection. The concentrations of certain proteins in serum such as creatine kinase, enolase and malate dehydrogenase were shown to correlate with tissue pathology while other proteins such as hemopexin, transferrin, and apolipoprotein, altered in concentration during later stages of the disease and did not correlate with tissue pathologies. The protein response to infection may be used to monitor disease progression and enhance understanding of the pathology of PD.

In this study, we wanted to evaluate genetic variation in resistance to infectious pancreatic necrosis (IPN) in a breeding population of rainbow trout. Two hundred families were challenged at a commercial test station, using methods that were previously developed for testing resistance to IPN in Atlantic salmon. Thirty-five days after the challenge the accumulated mortality was 26%. The results show that resistance to IPN is moderately heritable in the tested population (h2=0.30). The genetic correlation between IPN resistance and body weight was found to be low and non-significant. The significant additive genetic variation found in IPN resistance after a controlled challenge test gives promise for successful breeding for increased resistance to IPN in rainbow trout.

Pancreas disease (PD) is an important cause of losses in farmed salmonids in Norway, the United Kingdom and Ireland. As the spread of salmonid alphavirus (SAV), the causal agent, to naïve populations is of major concern to the farming industry, it is important to uncover the transmission routes of the virus. This study was conducted to investigate the potential for vertical transmission of SAV subtype 3. Progeny of broodstock with signs of late-stage PD and persistent RT-PCR signals for SAV were followed from fertilization to smoltification in an experimental facility. Fertilized ova were either not disinfected or taken through one of three different disinfection regimes. Also, ova and milt from uninfected broodfish from a different population were exposed to a cell-cultured strain of SAV 3 immediately before fertilization to simulate a viraemic phase in parent fish. A group of uninfected controls were also included in the study. Fertilized ova from bath exposed and negative control groups were double disinfected. Following fertilization, experimental fish went through a normal freshwater phase. However, fry were stressed at first feeding to enhance replication of possibly latent virus. Smoltification was induced by an artificial light regime, and experimental fish were followed to the late smoltification phase. Selected samples were investigated by real-time RT-PCR for SAV, by histology for evidence of PD and by serology for neutralising antibodies against SAV. All analysed samples of progeny were negative. This result shows that SAV 3 is not readily transmitted vertically from parents to offspring. Additional negative PCR results from salmon sampled in commercial hatcheries support these findings. Also, recent studies have shown that risk factors for the horizontal transmission route explain the vast majority of PD outbreaks in Norway. It is concluded that if it happens at all, vertical transmission is of minor importance in the spread of SAV 3.