Search Results (185)

Since 2022, numerous H5N1 highly pathogenic avian influenza virus (HPAIV) detections have been reported in wild and domestic mammals in North America. Although H5N1 HPAIV detections in dogs are rare, hunting dogs that retrieve waterfowl are at increased exposure risk due to their physical contact with reservoirs (waterfowl) and contaminated environments. A cross-sectional survey of hunters was conducted during 2024 to characterize hunting procedures, disease prevention practices, and interactions between humans and their hunting dogs to identify potential risks for zoonotic disease transmission. Descriptive analysis (N = 112) indicated a majority of participants considered their hunting dog as part of the family (93.8%), and less than half considered their dog a pet (42.9%). Of the 112 individuals, 96.4% did not utilize personal protective equipment (PPE) when handling a sick dog and 81.3% did not use PPE when handling harvested birds. This research demonstrated complex, sustained physical and personal connections between individuals and their hunting dogs. Additional research utilizing a One Health approach is necessary to define H5N1 HPAIV risk factors in hunting dogs and the environment’s role in the transmission of viruses among wildlife and domestic animals. Understanding zoonotic disease transmission in these populations can inform approaches to mitigate viral exposure. Full article

Brucellosis remains one of the most widespread zoonotic infections worldwide, causing serious veterinary, medical, and socio-economic consequences. The disease, caused by bacteria of the genus Brucella, affects a wide range of domestic and wild animals as well as humans, with global incidence potentially reaching 1.6–2.1 million new cases annually. The most effective approach to combating brucellosis is specific prevention through vaccination. Therefore, we conducted this review to summarize data from existing studies on modern strategies for brucellosis vaccination, types of vaccine platforms, their efficacy, safety, and applicability in veterinary and human medicine. We searched databases including PubMed, Scopus, and Web of Science to identify relevant scientific articles in English published from 1990 to 2025. The aim of this work is to conduct a systematic analysis of modern brucellosis vaccination strategies in livestock and humans, as well as to evaluate the prospects of new vaccine platforms. The review examines live attenuated, inactivated, subunit, vector, and DNA vaccines, as well as their immunological mechanisms of action, advantages, and limitations of application. This information allows for a better understanding of the mechanisms of protective immunity formation and challenges related to DIVA diagnostics (Differentiating Infected from Vaccinated Animals). The “One Health” concept demonstrated the interconnection between human, animal, and environmental factors, emphasizing the need for an interdisciplinary approach to brucellosis monitoring, prevention, and control. Vector vaccines based on influenza virus (Flu-BA), developed in Kazakhstan, have shown high promise, combining immunogenicity, protective efficacy, and a favorable safety profile. Promising directions remain mRNA vaccines, nanoparticles, CRISPR/Cas9 technologies, and mucosal vaccines. Full article

The H5N1 subtype of highly pathogenic avian influenza (HPAI) poses a major zoonotic threat due to its high fatality rate and capacity for cross species transmission. In early 2025, Argentina detected a novel triple reassortant A(H5N1) virus in Chaco Province, combining Eurasian, North American, and South American lineage segments. Genomic analyses of subsequent outbreaks in Buenos Aires and Entre Ríos confirmed persistence of this reassortant and additional HA substitutions (T204K, P251S) potentially linked to increased mammalian receptor affinity. Although PB2 sequences lacked canonical mammalian-adaptive markers (E627K, Q591K, D701N), all contained I292M, a mutation associated with human adaptation. Phylogenetic analyses revealed distinct genotypes and increasing divergence. These findings indicate ongoing viral evolution and adaptation within Argentina, emphasizing the urgent need for sustained genomic surveillance, timely data sharing, and integrated One Health strategies to mitigate zoonotic and socioeconomic risks associated with H5N1 spread in South America. Full article

The ongoing panzootic of the highly pathogenic avian influenza (HPAI) H5N1 virus, dominated by clade 2.3.4.4b, constitutes a significant global threat to wildlife, animal health, and public health. Once characterized by sporadic outbreaks, H5N1 has evolved into a sustained, year-round infection with an expanded host range that now includes numerous mammalian species. Its high pathogenicity is primarily driven by the acquisition of a polybasic haemagglutinin cleavage site, enabling systemic viral spread, alongside emerging endothelial and neurotropic properties that contribute to severe disease and high mortality in mammals. Although zoonotic transmission remains limited, H5N1 continues to accumulate mutations associated with mammalian adaptation, particularly within the haemagglutinin and polymerase complex. Notably, recent outbreaks in U.S. dairy cattle highlight the emergence of novel mammalian reservoirs with increased human exposure risk. Concurrently, vaccination strategies are advancing beyond traditional adjuvanted inactivated vaccines toward next-generation platforms, including mRNA and virus-like particle vaccines, designed for rapid deployment and broader immune protection. However, ongoing viral evolution, constrained vaccine availability, and gaps in coordinated surveillance underscore the urgent need for an integrated One Health approach to reduce panzootic risk. Full article

Zoonotic diseases account for approximately one billion cases of illness and millions of deaths globally each year. Increasing contact between humans and competent wildlife hosts elevates the risk of zoonotic spillover. Synanthropic bird species are key players in the transmission of zoonotic pathogens, including flaviviruses such as West Nile virus (WNV) and influenza A viruses like Avian Influenza Virus (AIV). Active surveillance of sentinel birds inhabiting urban areas allows for early detection of emerging pathogens before they cause zoonotic outbreaks. Despite nesting in close proximity to humans, the role of the house martin (Delichon urbicum) in the circulation of flaviviruses and AIV remains poorly understood. Here, we analyzed the presence of antibodies against flaviviruses and AIV in a colony of house martins from southwestern Spain. In addition, we aimed to detect amplicons of the matrix and nucleoprotein genes of AIV using RT-qPCR. While none of the samples tested positive for AIV by RT-qPCR, we observed an AIV seroprevalence of 2.13% based on non-subtyped ELISA. Notably, this is the first report of AIV-seropositive D. urbicum individuals captured in Spain. Moreover, we detected a flavivirus-group seroprevalence of 24.34%, similar to rates reported in the same house martin population between 2018 and 2020, suggesting widespread circulation of flaviviruses within this synanthropic species. These results support the hypothesis that house martins may participate in the transmission of these viruses between wild bird populations and humans in urban environments. Full article

Swine influenza virus (SIV) continues to evolve and possesses notable zoonotic potential, making it an important respiratory pathogen of concern for both the global swine industry and public health. Owing to antigenic drift, genetic reassortment, and regional lineage diversity, vaccine efficacy against SIV shows marked variability across different epidemiological contexts. Therefore, establishing appropriate animal models to dissect its pathogenic mechanisms, transmission characteristics, and immune response patterns is of critical importance. This review systematically summarises the animal models commonly used in SIV research, including mice, ferrets, guinea pigs, pigs, and non-human primates, and provides an integrated analysis across three core dimensions: pathological manifestations, viral replication kinetics, and immune architecture. The evidence indicates that substantial inter-model differences exist in pulmonary lesion distribution, transmission efficiency, mucosal immune development, and cellular immune complexity, which in turn define their functional roles in mechanistic studies, transmission research, and vaccine evaluation. Building on this framework, this review further emphasises the value of a tiered, multi-model strategy in SIV research. In vitro systems and mouse models are well suited for early mechanistic exploration and preliminary vaccine screening; ferret and guinea pig models facilitate the evaluation of transmission dynamics; and the pig model, as the natural host system, remains the critical platform for confirming protective efficacy, identifying potential immunopathological risks, and assessing translational relevance. Importantly, the potential occurrence of vaccine-associated enhanced respiratory disease under antigen-mismatched conditions highlights the need to evaluate both protective performance and immunological safety during vaccine development. Overall, rational integration of evidence across multiple models, anchored to the natural host, will improve the predictability and translational reliability of SIV vaccine research. Full article

Background/Objectives: Influenza A viruses cause seasonal epidemics of respiratory infections in humans, the severity of which can be mitigated by influenza vaccine use. Influenza A viruses circulating in pigs continue to pose a pandemic threat, as evidenced by the influenza virus that caused the 2009 pandemic, which originated in pigs. To understand the relative risk of emergence of influenza A viruses from pigs and to assess the potential role of the seasonal influenza vaccine in mitigating this risk, we evaluate the potential cross-protection afforded by the seasonal influenza vaccine against different clades of recently circulating swine influenza A viruses. Methods: The presence of cross-reactive antibodies in pre- and post-vaccination human serum samples was measured in haemagglutination and microneutralisation assays. Representative H1 swine influenza A viruses from different genetic lineages were tested against sera collected after administration of the seasonal influenza vaccine in healthy adult volunteers over a 6-year time-period. Results: Although a clade-dependent boosting of post-vaccination antibody titres was observed, protective titres often failed to be reached. There was heterogeneity in recognition by sera for the contemporary swine influenza A viruses, with the 1C.2.1 clade virus being well recognised in both assays, whilst very low pre- and post-vaccination antibody titres were observed against the 1A.3.3.2 clade (which emerged in pigs following the reverse zoonotic introduction from humans of the A/H1N1 pdm09 virus) by both assays. Conclusions: Seasonal influenza vaccines produce cross-reactive antibodies against some clades of influenza A viruses circulating in pigs, but not all. Depending on the lineage and clade of the virus, the seasonal influenza vaccine might have utility in the event of a swine variant outbreak in humans, whilst a specific vaccine against the outbreak strain is developed. Full article

This commentary provides an overview of the development of a zoonotic influenza vaccine, in response to the emergence of an H5N1 subtype virus from clade 2.3.4.4b in mid-2020. When development was initiated, the World Health Organization (WHO) had recommended four candidate vaccine viruses; the A/Astrakhan/3212/2020-like strain was selected as it provided good coverage of circulating viruses and, critically, was available. To facilitate regulatory approval, the licence of an existing zoonotic vaccine, Aflunov (A/turkey/Turkey/01/2005)—a pre-pandemic monovalent A/H5N1 adjuvanted with MF59 and manufactured using the egg-based platform—was duplicated, with the plan to submit a variation to the duplicate licence for the strain update. This was supported by a ferret immunogenicity study using pseudoviruses (allowing the work to be conducted at a lower biosafety level), in conjunction with clinical data from the original Aflunov licence application, and a US study (NCT05874713) on another candidate zoonotic vaccine manufactured using the cell-based platform. Qualification batches for characterisation studies were manufactured at-risk, until calibrated, homologous reagents were available, and the final product release and stability studies were conducted, with rolling provision of stability data to health authorities. The vaccine was initially approved with a shorter shelf-life, allowing early distribution in certain countries, with later extension of the shelf-life once data became available. In terms of procurement and logistics, early consultation between the European Commission and EU member states resulted in the award of a Framework Contract for the initial supply of 665,000 doses to 15 states. Learnings from the development of this vaccine may help to improve pandemic readiness in the future. Full article

Lassa virus (LASV), a member of the Arenaviridae family, is the causative agent of Lassa fever (LF), an acute zoonotic hemorrhagic disease transmitted by rodents, characterized by high infectivity and mortality rates. Due to the nonspecific nature of early clinical symptoms, the development of rapid, sensitive, and specific diagnostic methods is critical for effective epidemic control. In this study, the Lassa virus glycoprotein complex (LASV-G) was selected as the target antigen. High-affinity rabbit monoclonal antibodies were generated using a single B-cell cloning approach, and an AlphaLISA (Amplified Luminescent Proximity Homogeneous Assay)-based homogeneous, no-wash detection system was established. Sixteen LASV-G-specific monoclonal antibodies were isolated through flow cytometric sorting, and the optimal antibody pair (56–24) was identified by AlphaLISA pairing and performance screening. The established AlphaLISA system exhibited a limit of detection (LOD) of 0.025 ng/mL, representing approximately a 30-fold increase in sensitivity compared with conventional Enzyme Linked Immunosorbent Assay (ELISA), while reducing the total assay time to less than 30 min. The coefficient of variation (CV) was below 8%, and no cross-reactivity was observed with Ebola, dengue, yellow fever, Zika, or influenza virus antigens. These findings demonstrate that the developed AlphaLISA assay possesses high sensitivity, rapid detection, and good tolerance to matrix effects, significantly improving the efficiency of early LASV antigen detection. This work provides a potential platform for the rapid on-site screening and epidemiological surveillance of highly pathogenic viruses. Full article

Influenza (flu) is a common respiratory virus with seasonal global spread. Zoonotic viruses can occasionally cross species, leading to pandemic-level spread, and for flu viruses, this is considered an “antigenic shift”. The flu can be particularly severe during pregnancy due to immune system adaptations that occur during pregnancy, with prior global pandemics causing excess hospitalizations, deaths, and other complications in the mothers and the neonates. We aim to review the current literature with respect to novel avian H5N1 and the potential impact of infection with flu during pregnancy. A systematic literature search was conducted. Here we provide a rapid summary of epidemiology and understanding of viral spread, published risks of H5N1 in pregnancy, the unique physiologic, cellular, and molecular adaptations making H5N1 infection unique in pregnancy, implementation of an effective vaccine program in event of a pandemic specific to pregnant individuals, optimizing peripartum care for infected individuals, and direction for future research to direct vaccine strategy and mitigate risks in a future flu pandemic. Full article

Influenza A viruses exhibit broad host tropism, infecting multiple species including humans, avian species, and swine. Swine influenza virus (SIV), while primarily circulating in porcine populations, demonstrates zoonotic potential with sporadic human infections. In this investigation, we identified two H1N1 subtype swine influenza A virus strains designated A/swine/China/SD6591/2019(H1N1) (abbreviated SD6591) and A/swine/China/SD6592/2019(H1N1) (abbreviated SD6592) in Shandong Province, China. The GenBank accession numbers of the SD6591 viral gene segments are PV464931-PV464938, and the GenBank accession numbers corresponding to each of the eight SD6592 viral gene segments are PV464939-PV464946. Phylogenetic and recombination analyses suggest potential evolutionary differences between the isolates. SD6591 displayed a unique triple-reassortant genotype: comparative nucleotide homology assessments demonstrated that the PB2, PB1, NP, NA, HA, and NEP genes shared the highest similarity with classical swine-origin H1N1 viruses. In contrast, SD6592 maintained genomic conservation with previously characterized H1N1 swine strains, although neither of these two isolates exhibited significant intrasegmental recombination events. Through comprehensive sequence analysis of these H1N1 SIVs, this study provides preliminary insights into their evolutionary history and underscores the persistent risk of cross-species transmission at the human–swine interface. These findings establish an essential foundation for enhancing national SIV surveillance programs and informing evidence-based prevention strategies against emerging influenza threats. Full article

Influenza D virus (IDV), an emerging orthomyxovirus with zoonotic potential, infects diverse hosts, causes respiratory disease, and remains poorly characterized in China despite its global expansion. From October 2023 to January 2025, we collected 563 nasal swabs from cattle across 28 farms in Jilin Province, Northeast China, and identified seven IDV-positive samples (1.2%), recovering two viable isolates (JL/YB2024 and JL/CC2024). Full-genome sequencing revealed complete, stable seven-segment genomes with high nucleotide identity (up to 99.9%) to contemporary Chinese D/Yamagata/2019 strains and no evidence of reassortment. Maximum-likelihood and time-resolved Bayesian phylogenies of 231 global hemagglutinin-esterase-fusion (HEF) sequences placed the Jilin isolates within the East Asian D/Yamagata/2019 clade and traced their most recent common ancestor to approximately 2017 (95% highest posterior density: 2016–2018), suggesting a cross-border introduction likely associated with regional cattle movement. No IDV was detected in parallel surveillance of swine, underscoring cattle as the principal reservoir and amplifying host. Bayesian skyline analysis demonstrated a marked decline in global IDV genetic diversity during 2020–2022, coinciding with livestock-movement restrictions imposed during the COVID-19 pandemic. Collectively, these findings indicate that IDV circulation in China is sporadic and geographically localized, dominated by the D/Yamagata/2019 lineage, and shaped by multiple independent incursions rather than a single emergence. Both the incorporation of IDV diagnostics into routine bovine respiratory disease surveillance and cattle-import quarantine programs, and the adoption of a One Health framework to monitor potential human spillover and future viral evolution, were recommend. Full article

Background/Objective: The influenza virus remains one of the most prevalent respiratory pathogens, posing significant global health and economic challenges. According to the World Health Organization, the seasonal influenza virus infects up to 1 billion people and causes up to 650,000 deaths, annually. Despite influenza vaccination is the most effective available preventive strategy, its reliance on strain predictions and yearly updates limits its effectiveness. The virus’ ability to cause both epidemics and pandemics, driven by zoonotic transmissions, underscores its continuous threat. The ongoing H5N1 avian influenza outbreak is the perfect example, renewing concerns due to its ability to infect over 70 mammalian species and sporadically transmit to humans. This study aims to evaluate the protective potential of two human monoclonal antibodies against diverse and recent influenza virus strains. Method: PN-SIA28 and PN-SIA49 monoclonal antibodies were previously isolated from an individual undergoing seasonal influenza vaccination and with no known recent influenza virus exposure. Their breadth of recognition, neutralization, and conferred in vivo protection were assessed against multiple influenza viruses, including pre-pandemic strains. Structural analyses were performed to characterize antibody–antigen interactions for epitope identification. Results: Both antibodies recognize a broad range of strains and neutralize pre-pandemic avian influenza viruses, including the currently circulating H5N1 clade. Moreover, a structural analysis revealed that PN-SIA49 binds a conserved HA stem region, overlapping with epitopes recognized by other broadly neutralizing antibodies. Conclusions: These findings underscore the potential of broadly neutralizing antibodies as a basis for universal influenza countermeasures against both seasonal and pandemic threats. Additionally, they provide guidance for the design of targeted vaccine strategies to steer immune responses toward broadly protective epitopes. Full article

Influenza A viruses remain a persistent global health challenge due to their rapid antigenic evolution, zoonotic potential, and pandemic threat. Universal countermeasures targeting conserved viral components are urgently needed to enhance diagnostic, surveillance, and therapeutic capabilities. Here, we report the generation and characterization of a high-affinity monoclonal antibody (2D8 mAb) against the nucleoprotein (NP) of the H9N2 avian influenza virus, a subtype with increasing relevance to human infections. Importantly, 2D8 mAb exhibited robust cross-reactivity with a broad spectrum of influenza A viruses, including H1, H3, H5, H7, and H9 subtypes, while showing no cross-reactivity with unrelated viral pathogens. Epitope mapping identified its binding target as a highly conserved NP motif ³⁸RFYIQMCTEL⁴⁷, which is invariant across all major human influenza A lineages. Isotyping revealed 2D8 mAb to be of the IgG2b/κ subclass, with an exceptionally high titer (1:20,480,000) as determined by ELISA. Given the essential role of NP in viral replication and host adaptation, this antibody offers a powerful platform for next-generation diagnostic assays capable of detecting a wide range of human and zoonotic influenza A viruses using a single reagent. Moreover, it holds potential for guiding the design of universal antiviral strategies targeting structurally constrained regions of the influenza virus. Our findings provide a valuable resource for advancing pan-influenza A interventions, with direct implications for improving pandemic preparedness and strengthening global influenza surveillance in both clinical and public health settings. Full article

The widespread circulation of Eurasian avian-like H1N1 (EA H1N1) swine influenza virus poses significant zoonotic and pandemic risks worldwide. However, current diagnostic methods are difficult to deploy in the field, as they generally require specialized laboratory infrastructure and trained personnel. Here, we present a novel dual-signal detection platform that combines reverse transcription recombinase polymerase amplification (RT-RPA) with CRISPR/Cas12a technology for rapid, on-site EA H1N1 detection. We established an integrated one-tube assay by designing and optimizing RT-RPA primers targeting a conserved region of the hemagglutinin (HA) gene, together with engineered CRISPR/Cas12a guide RNAs exhibiting high specificity. The platform incorporates two complementary readout modes: real-time fluorescence monitoring and visual colorimetric detection using a smartphone. The assay shows excellent analytical specificity, with no cross-reactivity observed against other swine influenza virus subtypes or common swine pathogens, (including CSFV, PRRSV, PEDV, PCV, TGEV, and RV). The detection limit is 2 copies/μL, and the entire procedure can be completed within 30 mins using simple portable equipment. When evaluated on 86 clinical samples, the assay demonstrated 94.18% concordance with RT-qPCR. Compared with conventional diagnostic methods, this RT-RPA–CRISPR/Cas12a assay offers greater convenience and cost-effectiveness. Its strong potential for field-based rapid testing underscores promising application prospects in swine influenza surveillance and control programs. Full article