Maria K Dahle

Maria K Dahle
Norwegian Veterinary Institute · Fish Health Research Group

MSc PhD

About

138
Publications
17,725
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,835
Citations
Additional affiliations
January 2018 - present
UiT The Arctic University of Norway
Position
  • Professor
Description
  • 20% position
January 2017 - present
Norwegian Veterinary Institute
Position
  • Senior Researcher
September 2011 - December 2016
Norwegian Veterinary Institute
Position
  • Senior Researcher
Education
January 1998 - September 2002
University of Oslo
Field of study
  • Medical Biochemistry, Cell signaling

Publications

Publications (138)
Article
Full-text available
Protective cellular immune responses have been difficult to study in fish, due to lack of basic understanding of their T cell populations, and tools to study them. Cellular immunity is thus mostly ignored in vaccination and infection studies compared to humoral responses. High throughput sequencing, as well as access to well assembled genomes, now...
Article
Full-text available
Mucous membranes such as the gill and skin mucosa in fish protect them against a multitude of environmental factors. At the same time, changes in the molecular composition of mucus may provide valuable information about the interaction of the fish with their environment, as well as their health and welfare. In this study, the metabolite profiles of...
Article
Full-text available
Forskningsgruppen på Veterinærinstituttet, BioDirect, har laget en cellelinje fra rognkjeksens gjeller. Egenskapene og utseendet den har, tyder på at det er en celletype som ligner den man finner på innsiden av blodkar (endotel) eller på overflaten av gjeller (gjelle-epitelceller). Studiene av cellelinjen viser at den har lovende egenskaper som en...
Article
Full-text available
Piscine orthoreovirus (PRV-1) infection causes heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar) . The virus is also associated with focal melanized changes in white skeletal muscle where PRV-1 infection of macrophages appears to be important. In this study, we studied the macrophage polarization into M1 (pro-inf...
Article
Full-text available
The use of lumpfish (Cyclopterus lumpus) as a cleaner fish to fight sea lice infestation in farmed Atlantic salmon has become increasingly common. Still, tools to increase our knowledge about lumpfish biology are lacking. Here, we successfully established and characterized the first Lumpfish Gill cell line (LG-1). LG-1 are adherent, homogenous and...
Article
Full-text available
Salmon Gill Poxvirus Disease (SGPVD) has emerged as a cause of acute mortality in Atlantic salmon (Salmo salar L.) presmolts in Norwegian aquaculture. The clinical phase of the disease is associated with apoptotic cell death in the gill epithelium causing acute respiratory distress, followed by proliferative changes in the regenerating gill in the...
Article
Full-text available
Melanized focal changes in white skeletal muscle of farmed Atlantic salmon, “black spots”, is a quality problem affecting on average 20% of slaughtered fish. The spots appear initially as “red spots” characterized by hemorrhages and acute inflammation and progress into black spots characterized by chronic inflammation and abundant pigmented cells....
Article
Full-text available
Heart and skeletal muscle inflammation (HSMI), caused by infection with Piscine orthoreovirus-1 (PRV-1), is a common disease in farmed Atlantic salmon (Salmo salar). Both an inactivated whole virus vaccine and a DNA vaccine have previously been tested experimentally against HSMI and demonstrated to give partial but not full protection. To understan...
Article
Full-text available
no 5 PatoGen, 6002 Ålesund, Norway; morten@patogen.no (M.L.); havard@patogen.no (H.A.); magnus@patogen.no (M.D.) 6 VESO Vikan, 7810 Namsos, Norway; makoto.inami@veso.no (M.I.); marie.lovoll@veso.no (M.L.) Abstract: Piscine orthoreovirus 1 (PRV-1) is the causative agent of heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salm...
Article
Full-text available
Salmon gill poxvirus (SGPV) infection is a common denominator in many cases of complex gill disease in the Norwegian salmon farming industry and may, as a single agent infection, result in salmon poxvirus disease (SGPVD). Experiences from the field suggest that stress may be a decisive factor for the induction of SGPVD. Here we investigated the eff...
Article
Virus er noen fascinerende «skapninger». Selv om de bare er et molekylært kompleks av innpakket arvestoff, utnytter de vertens celler og lurer dens immunsystem lenge nok til at de rekker å oppformere og spre seg. Noen ganger gir dette dramatiske følger for vertens liv og helse. Mange ulike virus infiserer og gir sykdom hos norsk oppdrettslaks, med...
Article
Full-text available
The salmon gill poxvirus (SGPV) is a large DNA virus that infects gill epithelial cells in Atlantic salmon and is associated with acute high mortality disease outbreaks in aquaculture. The pathological effects of SGPV infection include gill epithelial apoptosis in the acute phase of the disease and hyperplasia of gill epithelial cells in surviving...
Article
Full-text available
Piscine orthoreovirus infects various salmonid fish species, and the infection is associated with diseases such as heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). There are no vaccines available or genetically selected resistant hosts that can efficiently control piscine orthoreovirus (PRV) infection. Currentl...
Article
Full-text available
Salmonid alphavirus (SAV) is the etiological cause of pancreas disease (PD) in Atlantic salmon (Salmo salar). Several vaccines against SAV are in use, but PD still cause significant mortality and concern in European aquaculture, raising the need for optimal tools to monitor SAV immunity. To monitor and control the distribution of PD in Norway, all...
Article
Full-text available
Salmon gill poxvirus (SGPV) can cause serious gill disease in Atlantic salmon (Salmo salar L.) and represents a significant problem to aquaculture industries in Northern Europe. Here, a single-tube multi-locus variable-number tandem-repeat (VNTR) analysis (MLVA) genotyping assay, targeting eight VNTR loci, was developed for studying the epizootiolo...
Article
Full-text available
Piscine orthoreovirus-1 (PRV-1) can cause heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar), but the line of events from infection, pathologic change, and regeneration has not been thoroughly described. In this study, the cellular localization and variation of PRV-1 RNA and protein levels were analyzed at differe...
Poster
Full-text available
Fish mucus has recently received significant interest in aquaculture research. Mucus on easily accessible surfaces such as skin and gills can be collected in a simple and non-invasive manner, and provide relevant information about the health status of the fish. However, the use of anaesthetics during the sampling may be a challenging source of bias i...
Presentation
Full-text available
Mucus on easily accessible surfaces such as skin and gills can be collected in a simple and non-invasive manner, and the metabolomic profile provides relevant information about the health status of the fish. However, the use of anesthetics during the sampling may be a challenging source of bias in comparative metabolomics of fish skin and gill mucus....
Article
Full-text available
Piscine orthoreovirus (PRV-1) can cause heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). The virus targets erythrocytes in the acute peak phase, followed by cardiomyocytes, before the infection subsides into persistence. The persistent phase is characterized by high level of viral RNA, but low level of viral pr...
Article
Full-text available
Bead-based multiplex immunoassays are promising tools for determination of the specific humoral immune response. In this study, we developed a multiplexed bead-based immunoassay for the detection of Atlantic salmon (Salmo salar) antibodies against Piscine orthoreovirus (PRV). Three different genotypes of PRV (PRV-1, PRV-2, and PRV-3) cause disease...
Article
Full-text available
Heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar) was first diagnosed in Norway in 1999. The disease is caused by Piscine orthoreovirus-1 (PRV-1). The virus is prevalent in farmed Atlantic salmon, but not always associated with disease. Phylogeny and sequence analyses of 31 PRV-1 genomes collected over a 30-year...
Article
Full-text available
Viral diseases represent one of the major threats for salmonid aquaculture. Survival from viral infections are highly dependent on host innate antiviral immune defense, where interferons are of crucial importance. Neutralizing antibodies and T cell effector mechanisms mediate long-term antiviral protection. Despite an immune cell repertoire compara...
Article
Full-text available
Piscine orthoreovirus (PRV) mediated diseases have emerged throughout salmonid aquaculture. Three PRV subtypes are currently reported as causative agents of or in association with diseases in different salmonid species. PRV-1 causes heart and skeletal muscle inflammation (HSMI) in Atlantic salmon (Salmo salar) and is associated with jaundice syndro...
Article
Full-text available
Salmonid red blood cells are the main target cells for Piscine orthoreovirus (PRV). Three genotypes of PRV (PRV-1,2,3) infect Atlantic salmon (Salmo salar), Chinook salmon (Onchorhynchus tshawytscha), Coho salmon (Oncorhynchus kisutch), rainbow trout (Onchorhynchus mykiss) and brown trout (Salmo trutta), and can cause diseases like heart and skelet...
Article
Full-text available
Infectious hematopoietic necrosis virus (IHNV) is endemic in farmed rainbow trout in continental Europe and in various salmonid fish species at the Pacific coast of North America. IHN has never occurred in European Atlantic salmon (Salmo salar) farms, but is considered as a major threat for the European salmon industry. Another virus, Piscine ortho...
Article
Piscine orthoreovirus (PRV) causes heart- and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). Erythrocytes are the main target cells for PRV. HSMI causes significant economic losses to the salmon aquaculture industry, and there is currently no vaccine available. PRV replicates and assembles within cytoplasmic structures...
Article
Heart‐ and skeletal muscle inflammation (HSMI) caused by infection with Piscine orthoreovirus (PRV) is one of the most common viral diseases in farmed Atlantic salmon (Salmo salar) in Norway, and disease outbreaks have been reported in most countries with large‐scale Atlantic salmon aquaculture. Currently there is no vaccine available for protectio...
Article
Full-text available
Piscine orthoreovirus (PRV-1) causes heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). Recently, a novel PRV (formerly PRV-Om, here called PRV-3), was found in rainbow trout (Oncorhynchus mykiss) with HSMI-like disease. PRV is considered to be an emerging pathogen in farmed salmonids. In this study, molecular an...
Article
Full-text available
Viral diseases pose a significant threat to the productivity in aquaculture. Heart- and skeletal muscle inflammation (HSMI) is an emerging disease in Atlantic salmon (Salmo salar) farming. HSMI is associated with Piscine orthoreovirus (PRV) infection, but PRV is ubiquitous in farmed Atlantic salmon and thus present also in apparently healthy indivi...
Data
One freeze-thaw cycle do not reduce the infectivity of PRV. Viral load in blood cells and plasma of injected fish in the PRV-Low (green) and PRV-Low-Frozen (blue) group (n = 6) in challenge experiment #2. (A) PRV RNA measured by RT-qPCR in blood and plasma, shown as individual and mean Ct-values at each week post challenge (wpc) (B) Amount of PRV σ...
Data
Histopathology in the heart of injected fish in challenge experiment #2. Histopathological score of (A) Epicardium, (B) Compactum, (C) Spongiosum and (D) Atrium. Shown as individual score and group mean from 2 to 8 weeks post challenge (wpc) for the PRV-High (red), PRV-Low (green), positive control (black) and negative control (grey) group (n = 6)....
Data
Pairwise sequence identities. Pairwise nucleotide (above diagonal) and amino acid (below diagonal) sequence identities (%) between concatenated coding regions of PRV. The concatenated amino acid sequence sets were constructed using the major gene product from each gene segment. (TIF)
Article
Full-text available
Heart and skeletal muscle inflammation (HSMI) is associated with Piscine orthoreovirus (PRV) infection and is an important disease in Atlantic salmon (Salmo salar) aquaculture. Since PRV infects erythrocytes and farmed salmon frequently experience environmental hypoxia, the current study examined mutual effects of PRV infection and hypoxia on pa-th...
Data
Relation between weight and oxygen saturation at ILOS. A. Weight of the individuals included in the hypoxia challenge test (HCT). Ctrl: non-infected controls, PRV: PRV-infected fish, PRV-H: PRV-infected fish exposed to periodic hypoxic stress. The lower and upper border of boxes indicates the 25th and 75th percentiles, respectively and the centerli...
Data
Pearson correlation analysis and linear regression analysis of PRV Ct values and hemoglobin (Hb) concentrations in fish sampled for disease development. The analysis was performed on merged data-points from 7 and 10 weeks post infection. Correlation and linear regression output between Hb concentrations and PRV Ct values in blood (A) and heart (B)....
Data
Weight of the experimental fish. All fish included in each group from Day 0 to 15 weeks post infection. Ctrl: non-infected controls, PRV: PRV-infected fish, PRV-H: PRV-infected fish exposed to periodic hypoxic stress. The lower and upper border of boxes indicates the 25th and 75th percentiles, respectively and the centerline indicates the 50th perc...
Data
K-factor of all fish in every group from Day 0 to 15 weeks post infection. Ctrl: non-infected controls, PRV: PRV-infected fish, PRV-H: PRV-infected fish exposed to periodic hypoxic stress. The lower and upper border of boxes indicates the 25th and 75th percentiles, respectively and the centerline indicates the 50th percentile. The upper and lower w...
Data
Table of number of fish sampled in the different groups and at specific time-points. Ctrl: non-infected controls, PRV: PRV-infected fish, PRV-H: PRV-infected fish exposed to periodic hypoxic stress. (PDF)
Data
Time-course of water oxygenation and temperature for each HCT. (TIF)
Data
ATP levels in every group at Day 0 and at 4 and 10 weeks post infection. Ctrl: non-infected controls, PRV: PRV-infected fish, PRV-H: PRV-infected fish exposed to periodic hypoxic stress. The lower and upper border of boxes indicates the 25th and 75th percentiles, respectively and the centerline indicates the 50th percentile. The upper and lower whi...
Data
Scoring criteria for histopathological evaluation of heart sections. (PDF)
Data
PRV Ct values in heart and blood. Ct values are presented as range (min to max) and +/- SEM. (PDF)
Data
Histological scoring of inflammatory changes in the heart–Heart rate. Development of inflammatory changes is displayed for fish included in the heart rate measurement at 10 weeks post infection (WPI). Ctrl: non-infected controls, PRV: PRV infected fish, PRV-H: PRV infected fish exposed to periodic hypoxic stress. Inflammatory changes in epicardium,...
Data
Pearson correlation analysis between PRV Ct values and heart rate. (TIF)
Article
Full-text available
A new disease in farmed rainbow trout (Onchorhyncus mykiss) was described in Norway in 2013. The disease mainly affected the heart and resembled heart and skeletal muscle inflammation (HSMI) in Atlantic salmon (Salmo salar L.). HSMI is associated with Piscine orthoreovirus (PRV), and a search for a similar virus in the diseased rainbow trout led to...
Data
Detection of dsRNA in erythrocytes from PRV-Om infected rainbow trout. Staining of double stranded RNA was performed on blood smears from rainbow trout sampled in a field outbreak from 2014. Blood smears were air dried before fixation in ice cold methanol. Slides were then rehydrated in PBS and blocked in PBS with 5% skimmed milk before staining wi...
Data
Trial 2 -Gross pathology. Injected rainbow trout 25 days post challenge. A) abdominal distension and pale gills. B) ascites and anaemia of internal organs. C) focal haemorrhage on abdominal wall. (TIF)
Data
Antiviral immune response qPCR data. (XLSX)
Data
Trial 1A-Tissue distribution of PRV-Om RNA. Virus analysis was performed by RT-qPCR targeting the PRV-Om segment S1 on heart, head kidney, spleen and blood) from virus-injected rainbow trout sampled at 0, 4 and 8 WPC. Indvidual Ct values (colored dots) and mean Ct levels (horizontal line) are shown. (TIF)
Data
Trial 3- weight curve. Weight curves based on the eight fish sampled per group at each time-point. Uninfected controls (grey), virus-injected fish (red), cohabitants (green) and stressed cohabitants (blue) are shown. Large dots represent individual measurements and the dotted trend lines show the group mean. The stressed cohabitants were exposed to...
Data
Trial 3 –haemoglobin/haematocrit curve and correlation. A) hemoglobin levels based on the eight fish sampled per group at each time-point. Uninfected controls (grey), virus-injected fish (red), cohabitants (green) and stressed cohabitants (blue) are shown. Large dots represent individual measurements and the dotted trend lines show the group mean....
Data
Statistical power test of trial 2 and 3. (DOCX)
Data
Trial 3-Effects of hypoxic stress on virus RNA detection in blood and heart in Atlantic salmon. Virus analysis were performed by RT-qPCR targeting the PRV-Om segment S1 on blood (A) and heart (B) from cohabitants sampled at 10 WPC and cohabitants (open bars) and stressed cohabitants (blue bars) at 16 WPC/end of trial. The stressed cohabitants were...
Article
Full-text available
Piscine orthoreovirus (PRV) is ubiquitous in farmed Atlantic salmon (Salmo salar) and the cause of heart and skeletal muscle inflammation. Erythrocytes are important target cells for PRV. We have investigated the kinetics of PRV infection in salmon blood cells. The findings indicate that PRV causes an acute infection of blood cells lasting 1–2 week...