Influenza A infection is frequently detected in marine mammals causing mortality events of different magnitude. In recent years, the highly pathogenic avian influenza (HPAI) H5N1 virus (clade 2.3.4.4b) has been rapidly expanding and infecting a new variety of avian and mammalian species, including marine mammals. Given this new epidemiological context, the objective of this work was to evaluate the influenza A virus infection of marine mammals stranded on the Basque Country coast. 38 marine mammals were studied (2012-2024), most of them (79%) being dolphins (striped dolphin, common dolphin, and common bottlenose dolphin). At necropsy, samples were collected from lung, intestine, and central nervous system when possible. During 2024, serum samples and oropharyngeal, nasal and faeces/rectum swabs were also collected. Real-time RT-qPCR was applied for influenza A virus detection in tissue and swab samples, and commercial ELISA was used to detect antibodies against influenza A viruses. All samples tested negative by PCR and ELISA. Despite the negative results obtained, we consider the continuation of the monitoring of influenza viruses in marine mammals essential by establishing collaboration networks and standardised protocols that allow us to gain insight into the epidemiology of influenza viruses in these species.

Cold shock proteins are small, highly conserved nucleic acid-binding proteins that help bacteria adapt to stress conditions. Aeromonas salmonicida subspecies salmonicida is a psychotropic, Gram-negative intracellular fish pathogen that causes furunculosis in fish. The role of cold shock proteins in the stress response in marine pathogens like A. salmonicida is unknown. In this study, we reported the role of cold shock protein A (CspA) in A. salmonicida physiology, stress response, and virulence in lumpfish (Cyclopterus lumpus). A. salmonicida ΔcspA was characterized using phenotypic tests and transcriptomics. A. salmonicida ΔcspA showed a reduction in survival at low temperatures (0 and 4ºC) and in ox bile containing (5%) conditions. Differential gene expression analysis showed 632 dysregulated genes in ΔcspA. Among these 632 differentially expressed genes (DEGs), 413 were upregulated, and 219 were downregulated. Most downregulated genes were related to the type III secretion system (T3SS). However, A. salmonicida ΔcspA was not fully attenuated in the lumpfish host but delayed fish mortality and reduced tissue colonization after systemic infection in contrast to the wild type strain. Overall, this study provides novel insight into the roles of CspA in virulence and the physiology of A. salmonicida.

Antibiotics in landfills create selection pressures on the microorganisms present, selecting for antibiotic resistance genes (ARGs) and antibiotic resistant organisms (ARO). The aim of this study was to assess whether landfills are hot-spots of antimicrobial resistance and whether landfills may contribute to global ARO diversity through ARG lateral gene transfer. Genome resolved metagenomic sequencing combined with sequence-search-based and deep learning tools were used to determine ARG diversity and prevalence from four active municipal landfills and their adjacent ground or surface water systems. Comparison to pristine and anthropogenic environments highlighted that landfill microbial communities contain distinct ARG signatures, including a broader diversity of ARGs. Plasmids made up 4.1-8.4% of assembled scaffolds and carried 5.4-12.0% of the identified ARGs in assembled data, depending on the sample type. Enriched ARG resistance mechanisms on mobile elements included multidrug resistance and antibiotic inactivation. The results indicate that landfills house a high diversity of antimicrobial resistance mechanisms and drug classes, with a moderate fraction encoded on mobile elements. Landfills are thus likely mixing grounds for ARG transfer and evolution of novel or augmented ARO lineages.

Phallus rubrovolvatus is a valuable edible fungus extensively cultivated in Guizhou Province, China. However, the changes in the soil microbiome throughout its growth cycle remain poorly understood. In this study, we collected 35 casing soil samples across five growth stages covering the entire 120-day cultivation cycle of P. rubrovolvatus and conducted metagenomic sequencing to examine alterations in soil microbial composition, diversity, key biomarkers, and functional potential. Our analyses revealed significant stage-dependent shifts in microbial community structure, with alpha diversity reaching its lowest at the primordium stage (Shannon of 5.12) and network complexity peaking at harvest stage (1.8-fold increase in connectivity). Through LEfSe analysis, we identified 37 stage-specific microbial biomarkers primarily affiliated with Actinomycetota and Acidobacteriota. Notably, Acidobacteriota biomarkers dominated at the primordium stage, while Nitrospirota enrichment characterized the harvest stage. Functional analyses revealed that membrane transport and energy metabolism pathways were enriched during early mycelial colonization, whereas secondary metabolite biosynthesis and signaling pathways became prominent during fruiting body maturation. Correlation analyses identified available nitrogen as the primary soil variable associated with microbial community composition. These findings provide foundational knowledge of microbiome dynamics during P. rubrovolvatus cultivation and suggest that microbiome-based management strategies may benefit from stage-specific interventions synchronized with fungal developmental transitions.

During the COVID-19 pandemic, educators rapidly pivoted their instructional approaches. While this period of disruption is behind us, we are left with a legacy of experiences that can continue to benefit learners. Open educational resources improve accessibility in the classroom, and for learners globally without access to well-resourced institutional libraries. In the 2023-2024 academic year, lecture videos for Veterinary Bacteriology and Mycology (a 3-credit, second year Doctor of Veterinary Medicine (DVM) course at the University of Saskatchewan) were published on YouTube. Two student cohorts were surveyed about their use of the videos, and YouTube analytics was used to describe how videos were accessed globally. Students generally favored these prerecorded videos, citing improved video quality (24%) and shorter duration (36%) compared to other courses where in-person lectures were filmed. Seventy-three percent of students reported that having these videos on YouTube improved accessibility. From August 2023 through December 2024, the YouTube channel received>230 000 views from 86 countries. Approximately 6% of views originated in Canada while 62% were from low- and middle-income countries. This exercise was a positive experience yielding an easy to access repository of content to share with learners locally and globally. Other instructors are encouraged to seek out opportunities for the creation of open resources. Future studies should assess the impacts of online video sharing platforms on student learning.

High Pathogenicity Avian Influenza (HPAI) of H5 subtype was detected year-round for the first time in Europe in 2022 and contributed to the largest European HPAI epizootic. The switch H5N8 to H5N1 virus subtypes heralded a substantial increase in cases in wild and domestic birds. The impact on domestic poultry production was substantial with 120 million birds dying or being culled to control the disease. This was attributed to an expansion in the host range of wild birds affected, with infection of orders of birds not previously described as susceptible. The consequence of transmission events into naive wild bird populations was often large-scale mortality, particularly in seabirds 2022-2023. Relatively high infection pressure provided opportunity for exposure and spillover to wild mammals principally the order Carnivora, exposed through predatory or scavenging behaviour. Other sporadic infections involved farmed fur animals and a single detection in a sheep in England, but no evidence of infection in other livestock species including dairy cattle. Human infections were rare and asymptomatic, associated with close contact with infected domestic birds. The epizootic was sustained by continuing evolution in the virus principally through genetic reassortment with selection and fixation of genotypes of high fitness in the avian population.

Highly pathogenic avian influenza clade 2.3.4.4b H5Nx viruses (HPAIVs) have caused significant mortality in wild birds. We investigated active avian influenza virus (AIV) infections and assessed seroprevalence based on general nucleoprotein-specific and H5-specific antibodies, in seabirds in Atlantic Canada during 2022-2023. Results were compared to seroprevalence data from 2011-2016 to evaluate changes in infection rates following the incursion of HPAIV. We sampled 1073 wild live birds belonging to 14 species. Active H5Nx infections were detected only in 2022, with the highest prevalence in Common Murres (64%), followed by Black-legged Kittiwakes (13%). Differences in seroprevalence were observed between years and species, with both Common Murres and Atlantic Puffins exhibiting higher rates after HPAIV incursion, particularly for anti-H5-specific antibodies. Seroprevalence also differed between locations, and age-related differences in exposure were observed with juvenile birds having much lower seroprevalence than adult birds, particularly among gulls. Despite no active infections being detected in 2023, high seroprevalence across species suggests persisting immunity and/or recent virus circulation. These findings underscore the importance of serological monitoring in tracking AIV dynamics, as antibody detection provides critical insights into past HPAIV exposure even when active infection rates are low.

Mine tailings are inhospitable to plant establishment because of substrate instability, nutrient limitation, heavy metals, and temperature fluctuations at the soil surface. Biological soil crusts (biocrusts) and their associated microbial communities can initiate primary succession and facilitate plant-soil interactions, thereby supporting ecosystem recovery. Here, we characterized soil bacterial communities beneath biocrusts along a successional gradient in abandoned and rehabilitated molybdenum-bismuth mine tailings in Western Boreal Quebec. We collected 125 soil samples from bare soil, cyanobacterial-, chlorolichen-, and bryophyte-dominated biocrusts, as well as from a mixed bryophyte-lichen cover layer. Bacterial communities were assessed using amplicon sequencing (16S rRNA and nifH genes) and linked to soil physicochemical properties to infer functional potential. Soil pH, electrical-conductivity, and sulfur content were associated with bacterial diversity (distance-based redundancy analysis, R2 = 0.20, p<0.01). Rehabilitated sites exhibited moderate relative abundances of Proteobacteria (6.9%), whereas Actinobacteriota prevailed in nutrient-poor abandoned sites (17.1%), consistent with oligotrophic adaptation. Additionally, functional potential from chemoheterotrophy in later stages was associated with sulfur-oxidation (Spearman's ρ = 0.6, p<0.05), with anoxygenic photoautotrophs potentially contributing to sulfur oxidation. Overall, our study indicates that bacterial communities may contribute to soil stabilization and could serve as key bioindicators of restoration success.

Unprecedented seabird mass mortality events (MMEs) were reported in multiple European countries in 2022 and 2023. These events were attributed to Clade 2.3.4.4b H5N1 high pathogenicity avian influenza viruses (HPAIVs). In Denmark, populations of Sandwich Terns (Thalasseus sandvicensis) and Black-headed Gulls (Chroicocephalus ridibundus) were significantly impacted. Sandwich Tern mortality occurred primarily between May and June of 2022 and was caused by the HPAIV genotype EA-AB. From 2022 to 2023, Danish Sandwich Tern populations decreased by 36%. Sandwich Terns commonly nest within Black-headed Gull colonies, allowing for direct contact between the species. Despite their proximity, in 2022, neither adults nor chicks of Black-headed Gulls exhibited morbidity associated with HPAIV. During the autumn of 2022 and the winter 2022/23 a novel clade 2.3.4.4b H5N1 HPAIV, genotype EA-BB, emerged in Black-headed Gulls. The new genotype caused the death of at least 3000 adult Black-headed Gulls in Denmark (i.e., >1.8% of the Danish breeding population) in the spring of 2023. Notably, in 2023 Sandwich Tern chicks, but not adults, in contact with Black-headed Gulls were affected by mass mortality. These observations suggest that adult Terns in 2023 were less susceptible to HPAIV infection, mitigating the impact of MMEs.

Extracellular vesicles (EVs) are small, lipid bi-layered structures released from various cell types throughout the body. These structures are responsible for the delivery of proteins, compounds, and communication signals across spatial distances. EVs are highly important to diverse biological processes within mammalian systems, including roles in cellular maintenance and homeostasis of physiological conditions and response to infection, and they have the potential to serve as diagnostic hallmarks of infection. Despite these advances and promise, knowledge of the dynamics of EV production and composition during bacterial infection is limited. In this study, we characterize phenotypic traits and proteome remodeling of host EVs derived from murine models during a state of infection by the bacterial pathogen, Klebsiella pneumoniae, compared to an uninfected control. Phenotypic profiling defines consistent size, diameter, and number of EVs from samples across infectious states, whereas a closer look into molecular regulation at the protein level defines core and infection-exclusive proteomes. Within the core proteome (i.e., protein detection common between plasma from uninfected vs. infected samples) clustering based on infectious state was observed and significant increase (p<0.01) in fibrinogen production upon infection were reported. Conversely, assessment of the infection-exclusive EV proteome supported detection of EVs by Gene Ontology Cellular Component classification revealed an enrichment of proteins associated with blood microparticles, membrane-bound, and the extracellular region, and highlighted the production of immune-associated proteins classified by Gene Ontology Biological Processes. Overall, this study emphasizes complex reprogramming of the host EV proteome upon exposure to K. pneumoniae within a murine model of infection and proposes protein-level signatures indicative of bacterial infection.