Norwegian Veterinary Institute

Swine may act as 'epidemiological bridges' and reservoirs for the emergence of novel zoonotic influenza viruses with pandemic potential. While bidirectional exchange of influenza A viruses at the swine-human interface is well recognised, data on the extent of interspecies transmission are limited. We analysed the post-seasonal geometric mean titre (GMT) of influenza A(H1N1)pdm09 antibodies in humans and the seasonal prevalence of influenza A(H1N1)pdm09 antibodies in unvaccinated swine from 2009/2010-2022/2023 per county in Norway to search for evidence of interspecies transmission. We explored correlations at the national and individual county level and investigated possible associations by running a negative binomial regression model. Additionally, we distributed an influenza vaccination questionnaire to veterinarians and farmers working with swine to assess vaccination uptake and calculated total response rates per county and overall. The time series of H1N1pdm09 antibodies from humans and swine show significant positive correlations both across (0.8 Pearson correlation coefficient) and within certain individual counties, with especially high correlations in Innlandet (0.9), Vestland (0.8) and Rogaland (0.7) Counties. Our regression analysis revealed a significant positive association between the annual GMT of H1N1pdm09 antibodies in humans, the annual seroprevalence of H1N1pdm09 antibodies in swine, and the density of swine farms in counties. Vaccination uptake was 39% and 50% in farmers and veterinarians, respectively. Our findings indicate a temporal relationship between the disease in humans and swine; suggesting spillover, environmental factors facilitating disease spread, and/or indirect relationships driven by unknown factors. The time series of H1N1pdm09 antibodies in humans and swine shows significant correlations. Regression analysis links GMT of H1N1pdm09 antibodies in humans to seroprevalence of H1N1pdm09 in swine and density of swine farms. This indicates a temporal relationship possibly due to spillover, shared risk factors or indirect relationships driven by unknown factors. The influenza vaccination survey showed a 39% uptake among farmers and 50% among swine veterinarians.

Barley has been proposed as a promising and more sustainable alternative to common cereals in poultry diets. However, the use of barley in poultry diets has historically been limited, mainly due to observed negative impact on gastrointestinal health and performance. In this study, we explored the potential of incorporating barley into broiler diets, focusing on effects on Clostridium perfringens, the causative agent of necrotic enteritis in poultry, and the cecal microbiota. The study included four diets containing 54% barley, with or without the addition of non-starch polysaccharide-degrading enzyme (NSPase), and one control diet without barley. The main ingredients were ground to either a fine or coarse particle size. Low C. perfringens levels were maintained in the intestines of broilers fed barley-based diets, suggesting that barley did not predispose to necrotic enteritis in this study. Broilers fed the coarse barley-based diet with NSPase exhibited the lowest abundance of Lactobacillus and the highest abundance of Faecalibacterium, and their cecal microbiota resembled that of the group fed the control diet. In contrast, broilers fed the coarse barley-based diet without NSPase exhibited the highest abundance of Lactobacillus among all groups in this study, along with a lower abundance of Faecalibacterium. Among the groups that received diets with finely ground barley, regardless of NSPase supplementation, there was no clear shift in the abundance of the two bacterial genera. These observations suggest that feed particle size and NSPase supplementation influence the composition of the cecal microbiota in broilers fed barley-based diets, and that these factors could be utilized as tools to mitigate undesirable health effects associated with the inclusion of barley in poultry diets. The findings of this study highlight the potential of including increased levels of barley in broiler diets without compromising health or performance. Further studies are warranted to explore the effects of similar inclusion levels of different barley varieties on gastrointestinal health and microbiota under varied environmental conditions.

In 2023, highly pathogenic avian influenza (HPAI) heavily affected gulls in Europe. In July, a mass mortality event was reported in the black-legged kittiwake (Rissa tridactyla) breeding colony at Ekkerøy in Northern Norway. The cause was confirmed to be infection with the HPAI H5N1 clade 2.3.4.4b virus, genotype EA-2022-BB. We describe the outbreak in kittiwakes, including pathological and virological investigations, and discuss the management and zoonotic potential. With more than 15,000 dead birds reported, we estimate that the outbreak caused a reduction in the kittiwake population at Ekkerøy of at least 50%. Diseased birds exhibited neurological signs. Necropsies of 10 birds revealed a peracute fatal systemic disease, with severe lesions in the brain and pancreas co-localizing with viral RNA and antigen. Vascular expression of α2,3-linked sialic acids (SAs) and viral RNA/antigen may reflect hematogenous viral spread. Further studies should investigate the long-term impact of HPAI on kittiwake populations.

ABSTRACT In recent years, European countries have intensified efforts to control or limit the spread of invasive freshwater crayfish and the crayfish plague pathogen Aphanomyces astaci , while working to conserve native species such as the noble crayfish ( Astacus astacus ). Although crayfish shed relatively low amounts of DNA into their environment, environmental DNA (eDNA) approaches have proven effective for detecting their presence. A range of protocols and equipment is currently used in eDNA‐based monitoring of freshwater crayfish. To evaluate how methodological variation influences detection accuracy, we conducted the first European interlaboratory ring test using eDNA to detect A. astacus , the invasive signal crayfish Pacifastacus leniusculus , a chronic carrier of A. astaci , and the pathogen itself. The aim is to harmonize monitoring methods for crayfish and disease surveillance across laboratories. Eleven teams from thirteen European countries participated, each using its own equipment and protocols to collect and filter water from indoor tanks and outdoor ponds where the presence of A. astacus and P. leniusculus had been experimentally manipulated, as well as from a natural lake containing a P. leniusculus population. The resulting samples were analyzed in each team's laboratory. Despite methodological differences, all teams successfully detected DNA from both crayfish species in indoor tanks (3–10 crayfish/m 3 ). However, detection accuracy declined in outdoor ponds where crayfish density was an order of magnitude lower (0.32 crayfish/m 3 ). Detection was most variable for A. astaci , likely due to its very low prevalence in the host stock. Our study demonstrates the challenges of achieving consistent eDNA results across laboratories and highlights the importance of interlaboratory comparisons. It also underscores the need to identify sources of variability and error, an essential step toward developing robust and standardized protocols. This multinational intercalibration and exchange of knowledge improved methodology and enhanced reliability in crayfish detection.

The use of robotic vision to cut deformable food objects is a challenge in robotics that has the potential to improve autonomy and create new opportunities in industries such as medicine, the food industry, and services. While cutting rigid objects is relatively simple, cutting deformable objects like food items, which change shape during the cutting process, is a significant challenge that requires advances in various aspects of robotics, including vision, modeling, hardware design, and control. This paper discusses recent developments in vision-based approaches for robots cutting food items and highlights the main challenges that must be overcome to succeed in this task and outline some potential future research directions.

Abattoirs provide a valuable opportunity to assess the impact of porcine pleuropneumonia, as lesions caused by Actinobacillus pleuropneumoniae remain visible at postmortem inspections. This study evaluated an artificial intelligence (AI)-based system for scoring pleurisy in slaughtered pigs under field conditions. The trial was conducted in a Norwegian abattoir, where a collaborative robot automatically captured carcass images. A convolutional neural network assessed pleurisy according to the “ Pleurisy Evaluation on the Parietal Pleura ” method. In parallel, veterinarians and meat inspectors from the Norwegian Food Safety Authority scored pleurisy using a binary system, based on the presence or absence of lesions exceeding 15 cm. Moreover, a subset of 500 images were scored by two academic veterinarians (one has been working for decades in farm animals’ pathology, and the other is a PhD student studying farm animals’ respiratory pathology) using the “ Pleurisy Evaluation on the Parietal Pleura ” method. The same veterinarians recorded lesions larger than 15 cm. The AI system detected pleurisy in 9.80% of pigs, demonstrating high specificity and sensitivity (> 95%) compared with veterinary assessments of digital images. Norwegian meat inspection staff reported pleurisy in 5.18% of pigs, showing a moderately strong correlation with the AI system (Spearman’s ρ = 0.67). Very large lesions were identified in 3.4-4.6% of digital images by veterinarians. Prevalence results aligned with historical data, being consistent with the high health status of Norwegian pig herds. Lesions were mainly located on the caudal chest wall, supporting Actinobacillus pleuropneumoniae as a major causative agent. This study highlights the potential of AI-driven tools to enhance disease surveillance, reduce observer variability, and facilitate large-scale data collection in slaughterhouse environments. • An AI-based system was evaluated for scoring pleurisy in pigs, under industrial abattoir conditions. • The AI-based system demonstrated good performance when compared to veterinary assessments. • The AI-based system outperformed routine scoring provided by the official meat inspection personell. • Data provide reliable prevalence of lesions indicative of Actinobacillus pleuropneumoniae infection in Norwegian pig herds.

Abstract The ongoing biodiversity crisis requires policy tools to establish baselines and assess biodiversity status. Reindeer and caribou (Rangifer tarandus) are iconic ungulates in the Arctic and subarctic, but populations are declining. Although the species is considered vulnerable globally in the International Union for Conservation of Nature [IUCN] Red List, more detailed policy tools at the population level would allow for targeted conservation efforts nationally. We developed an environmental quality standard (or norm) for reindeer populations to evaluate their overall status and put complex variation and change into simple status categories (poor, medium, and good) based on sets of quantitative indicators for 1) population performance, genetic diversity, and health status; 2) available lichen resources; and 3) loss of seasonal habitat and connectivity. We implemented the environmental quality standard for 10 national and 14 smaller wild reindeer areas (populations) in Norway. Except for 1 area with good status, all others ranged from medium (n = 11) to poor quality (n = 12). More than half of the populations had medium (n = 7) or poor (n = 6) status for 1 or more population performance indicators, with negative trends in calf body mass and recruitment in several populations. High loss of genetic diversity gave poor status in 4 small and isolated populations, and 2 populations with chronic wasting disease scored poor on health status. The status of lichen resources was medium (n = 20) or good (n = 3), with 1 exception. However, lichen time series data were not available to evaluate temporal trends to assess overgrazing. Loss of connectivity (poor; n = 7) was more problematic than loss of seasonal habitat (n = 3). The poor availability of high‐quality empirical data, particularly on population performance, has limited the ability to fully assess the conservation status of several small populations. The environmental quality standard provides an important step towards operationalizing management and aiding in securing the long‐term conservation of wild reindeer. We discuss further improvements and the potential usefulness of this approach for other large mammals.

Abstract The gut microbiota is vital to host health, yet the relative influence of host traits and environmental factors on fish gut microbiota dynamics remains underexplored. We investigated the ecological dynamics of Atlantic salmon (Salmo salar) gut microbiota, by analysing 847 samples from wild and farmed salmon across diverse geographic regions, developmental phases, and associated diet and environmental microbiota. Farmed salmon exhibits reduced microbial diversity and distinct community composition with increased Firmicutes and reduced Proteobacteria compared to wild salmon. Microbial diversity declined with advancing developmental phases notably due to reduced Proteobacteria and expanded Mycoplasma. Diet was the primary contributor (∼23%) to farmed salmon microbiota, with environmental inputs varying by region and phase. These findings highlight the importance of aquaculture practices guided by microbiota insights, while emphasize the need to preserve microbial diversity in wild populations to enhance resilience against environmental pressures, contributing to both sustainable farming and conservation strategies.

ABSTRACT Renibacterium salmoninarum is the causative agent of bacterial kidney disease (BKD) and has been isolated from northern European salmonid farms since the 1960s. The bacterium has been detected only sporadically in Norway during the last decades, but the country experienced several geographically spread outbreaks since December 2022. The phylogenomic relationships of R. salmoninarum isolates associated with the epizootics ongoing on the West Coast and in Mid-Norway were explored using a whole genome sequencing approach. A broad overview of the phylogeography of this pathogen was gained through sequencing and analysis of a collection of isolates from Norway (n=67), Iceland (n=12), Denmark (n=12), and the Faroe Islands (n=1), along with a collection of 109 publicly available sequences. We identified two distinct contemporary clades of R. salmoninarum causing BKD in Norway in the period 2022-2024. Both clades belong to the expanding, aquaculture-associated Lineage 1. The epidemiological picture appears consistent with contemporary aquaculture operations, raising questions on the effectiveness or practice of current biosecurity practices towards R. salmoninarum . Our work also describes a hitherto undescribed lineage (Lineage 3), predominantly from Iceland, where BKD is considered endemic. The detection of endemic reservoirs of R. salmoninarum in European water systems underscores the potential for ongoing pathogen circulation independent of acute outbreaks. This finding emphasizes the importance of further investigation of the mechanisms of pathogen persistence, particularly within environments related to aquaculture, where chronic infection reservoirs could compromise disease management and biosecurity. IMPORTANCE Renibacterium salmoninarum , the causative agent of bacterial kidney disease (BKD), is a chronic salmonid pathogen that often presents subclinically, complicating detection and control. Effective management of BKD is therefore crucial for sustainable aquaculture and wild fish conservation. Recognizing the need for comprehensive sampling, previous studies have underscored the importance of a global isolate collection to better understand the epidemiology of the pathogen. While the slow genetic evolution and highly conserved genome of the bacterium have reduced the resolution of conventional typing methods in the past, applying whole genome sequencing has enabled its molecular tracing at the outbreak level. Here, we present the largest phylogenomic analysis of R. salmoninarum to date, including sequences from Denmark, Iceland, and the Faroe Islands for the first time. This expanded dataset elucidates past and present movements of the pathogen in European waters, providing actionable insights to support development of targeted BKD management and biosecurity strategies.