Immersion challenge model for Flavobacterium psychrophilum infection of Atlantic salmon (Salmo salar L.) fry.

Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease (CWBD) and rainbow trout fry syndrome (RTFS), which affect salmonids. To better understand this pathogen and its interaction with the host during infection, including to support the development of resistant breeds and new vaccines and treatments, there is a pressing need for reliable and reproducible immersion challenge models that more closely mimic natural routes of infection. The aim of this present study was to evaluate a challenge model developed previously for rainbow trout for use in Atlantic salmon. First, preliminary challenges were conducted in Atlantic salmon (n = 120) and rainbow trout (n = 80) fry using two F. psychrophilum isolates collected from each fish species, respectively; fish had been pretreated with 200 mg/L hydrogen peroxide for 1 h. Thereafter, the main challenge was performed for just one F. psychrophilum isolate for each species (at 2 × 107 CFU/mL) but using larger cohorts (Atlantic salmon: n = 1187; rainbow trout: n = 2701). Survival in the main challenge was 81.2% in Atlantic salmon (21 days post-challenge) and 45.3% in rainbow trout (31 days post-challenge). Mortalities progressed similarly during the preliminary and main challenges for both species, demonstrating the reproducibility of this model. This is the first immersion challenge model of F. psychrophilum to be developed successfully for Atlantic salmon.

Multidetector Computed Tomography (MDCT) Findings of Complications of Acute Cholecystitis. A Pictorial Essay.

Acute cholecystitis stands out as one of the most common surgical pathologies that should always be considered in a right-upper abdominal pain emergency. For this, the importance of a correct diagnosis is well described. However, it has been demonstrated that the simple combination of clinical (pain, Murphy's sign) and laboratory (leukocytosis) parameters alone does not provide for ruling in or ruling out the diagnosis of this condition, unless accompanied by a radiological exam. For a long time, and still today, ultrasonography (US) is by far the first-to-proceed radiologic exam to perform, thanks to its rapidity and very high sensibility and specificity for the diagnosis of simple acute cholecystitis. However, acute cholecystitis can undergo some complications that US struggles to find. In addition to that, studies suggest that multidetector computed tomography (MDCT) is superior in showing complicated forms of cholecystitis in relation to sensibility and specificity and for its capability of reformatting multiplanar (MPR) reconstructions that give a more detailed view of complications. They have shown to be useful for a precise evaluation of vascular complications, the anatomy of the biliary tree, and the extension of inflammation to surrounding structures (i.e., colitis). Therefore, based also on our experience, in patients with atypical presentation, or in cases with high suspicion for a complicated form, a MDCT abdomen scan is performed. In this review, the principal findings are listed and described to create a CT classification of acute complications based on anatomical and topographic criteria.

Detection of Betanodavirus in experimentally infected European seabass (Dicentrarchus labrax, Linnaeus 1758) using non-lethal sampling methods.

One of the major disease threats affecting the Mediterranean aquaculture industry is viral encephalopathy and retinopathy (VER). The target organs for Betanodavirus detection are the brain and eyes, obtained through lethal sampling. This study aimed to evaluate the efficacy and suitability of non-lethal samples for detecting Betanodavirus in European seabass (Dicentrarchus labrax). European seabass juveniles were infected with Betanodavirus, by either an intramuscular injection or immersion (107 TCID50 /ml and 106 TCID50 /ml, respectively), and samples collected 7, 15 and 30 days post-infection (dpi). The brain was collected as a lethal sample, and gills, caudal fin and blood as non-lethal tissues for detecting Betanodavirus by quantitative reverse transcription PCR (RT-qPCR). The presence of virus in non-lethal tissues was inconsistent, with lower viral loads than in the brain. For blood, higher viral loads were detected in intramuscular-infected fish at 15 dpi until the end of the challenge. Serum antibodies against Betanodavirus were assessed using an enzyme-linked immunosorbent assay (ELISA). Antibodies were detected as early as 7 dpi, with higher mean antibody titres at 15 and 30 dpi. The presence of Betanodavirus-specific antibodies indicates that this is a suitable evaluation method for detecting early stages of the infection.

Low levels of microplastics (MP) in wild mussels indicate that MP ingestion by humans is minimal compared to exposure via household fibres fallout during a meal.

Microplastics (MPs) are the most numerous debris reported in marine environments and assessment of the amounts of MPs that accumulate in wild organisms is necessary for risk assessment. Our objective was to assess MP contamination in mussels collected around the coast of Scotland (UK) to identify characteristics of MPs and to evaluate risk of human exposure to MPs via ingestion of mussels. We deployed caged mussels (Mytilus edulis) in an urbanised estuary (Edinburgh, UK) to assess seasonal changes in plastic pollution, and collected mussels (Mytilus spp and subtidal Modiolus modiolus) from eight sampling stations around Scotland to enumerate MP types at different locations. We determined the potential exposure of humans to household dust fibres during a meal to compare with amounts of MPs present in edible mussels. The mean number of MPs in M. modiolus was 0.086 ±â€¯0.031 (SE, n = 6)/g ww (3.5 ±â€¯1.29 (SE) per mussel). In Mytilus spp, the mean number of MPs/g ww was 3.0 ±â€¯0.9 (SE, n = 36) (3.2 ±â€¯0.52 (SE) per mussel), but weight dependent. The visual accuracy of plastic fibres identification was estimated to be between 48 and 50%, using Nile Red staining and FT-IR methodologies, respectively, halving the observed amounts of MPs in wild mussels. We observed an allometric relationship between the number of MPs and the mussels wet weight. Our predictions of MPs ingestion by humans via consumption of mussels is 123 MP particles/y/capita in the UK and can go up to 4620 particles/y/capita in countries with a higher shellfish consumption. By comparison, the risk of plastic ingestion via mussel consumption is minimal when compared to fibre exposure during a meal via dust fallout in a household (13,731-68,415 particles/Y/capita).