J Microbiol Biotechnol. 2025 Dec 15;35:e2510027. doi: 10.4014/jmb.2510.10027.
ABSTRACT
The 2009 pandemic H1N1 (pdm09) virus is both zoonotic and reverse-zoonotic, transmitting from swine to humans and vice versa. During the early zoonotic phase, immediately after the species jump and before substantial antigenic drift had accumulated, recombinant vaccine strains bearing hemagglutinin (HA) and neuraminidase (NA) from early pdm09 viruses often replicated poorly in embryonated chicken eggs (ECEs), contributing to delays and shortages in vaccine supply. Developing seed strains that are more productive in ECEs while preserving antigenicity and minimizing mammalian pathogenic potential is therefore essential for future pandemic preparedness. Efficient egg replication requires a balanced activity between HA and NA and their coordinated interaction with the polymerase subunit PB2. To this end, we generated PR8-derived recombinants combining PB2 backbones with distinct polymerase activities with targeted HA and NA modifications and edits to segment-specific 3' and 5' noncoding regions (NCRs). Comparative analysis of viral titers, together with sequence-based predictions of mutation effects, identified genotypes that improved replication in eggs while minimizing antigenic variations and reducing markers associated with mammalian virulence. Although further enhancement of viral yield is still warranted, these results delineate practical design principles, favoring balanced tuning of HA-NA functions, PB2 compatibility, and NCR context over large receptor-shift mutations, for engineering influenza seed strains. This work provides actionable guidance to support vaccine development and strengthen One-Health-oriented pandemic preparedness.
PMID:41407328 | DOI:10.4014/jmb.2510.10027
Virol J. 2025 Dec 7. doi: 10.1186/s12985-025-03035-8. Online ahead of print.
ABSTRACT
Newcastle Disease (ND) remains a major threat to poultry production worldwide, particularly in regions where it is endemic, like Southern Asia. The disease is caused by virulent forms of avian paramyxovirus-1, commonly termed Newcastle Disease Virus (NDV), a highly contagious virus with significant genetic diversity and evolving pathogenicity. This study aimed to molecularly characterize NDV isolates obtained from chickens and pheasants during the 2020/21 ND outbreaks in Nepal, to understand their genetic makeup, phylogenetic relationships, and implications for control strategies. Necropsy samples, including trachea, liver, intestine, spleen, lungs, heart, and proventriculus were collected from ten birds. Isolates from five clinical samples were typed as NDV by hemagglutination and hemagglutination inhibition (HA/HI) assays and were subjected to whole genome sequencing (WGS). Full genomes of 15,192 nucleotides were recovered from each isolate. Fusion (F) gene sequence analysis revealed the presence of multi-basic cleavage site motif 112RRQKRF117 in all isolates, indicative of virulent strain and suggesting a potentially velogenic or mesogenic phenotype. Phylogenetic analyses consistently classified all isolates within genotype VII.2 of class II NDV. Further comparative analysis indicated a close genetic relationship between the Nepalese isolates and strains reported from India and Bangladesh, and BEAST analysis suggested Southern Asia as the likely source of introduction into Nepal. These viral genomes provide additional insight into contemporary NDV circulating in an area of endemicity.
PMID:41354805 | DOI:10.1186/s12985-025-03035-8
J Vet Sci. 2025 Nov;26(6):e81. doi: 10.4142/jvs.25069.
ABSTRACT
IMPORTANCE: The Y439 lineage 01310 E20 H9N2 vaccine strain currently used in South Korea has undergone extensive egg adaptation, resulting in substantial changes, including an 18-amino acid neuraminidase (NA) stalk deletion. Additionally, both early and late 01310 passages inherently harbor an N-glycan at hemagglutinin (HA) residue 158-160 (HA158) that may interfere with virus-specific antibodies.
OBJECTIVE: We aimed to develop a high-yield vaccine strain without egg passaging and to overcome the limitations of the conventional vaccine strain that may compromise immunogenicity.
METHODS: We introduced a genetically modified 01310 PB2 gene (310-MVV: I66M, I109V, I133V) to increase replication in embryonated eggs and removed the N-glycan at HA158 and restored the NA stalk to improve immunogenicity. The resulting strain was assessed for egg replication and immunogenicity in chickens.
RESULTS: The resulting vaccine strain (310-SNS-193D-MVV) grew efficiently in embryonated eggs without repeated passaging. As restoring the NA stalk alone was insufficient to enhance NA-specific immunity, simultaneously removing the N-glycan at HA158 markedly increased NA-specific antibody responses and neutralizing antibody titers across multiple H9N2 lineages. Additionally, incorporating 310-SNS-193D-MVV into a bivalent formulation with a Y280 lineage strain conferred broader coverage without evidence of immune interference.
CONCLUSIONS AND RELEVANCE: These findings underscore how PB2, HA, and NA targeted genetic modifications can improve H9N2 vaccine productivity and immunogenicity. These strategies are not limited to our H9N2 strain and can be applied to other low propagating or NA stalk-deleted virus strains.
PMID:41332001 | PMC:PMC12703918 | DOI:10.4142/jvs.25069
Poult Sci. 2025 Nov 13;105(1):106108. doi: 10.1016/j.psj.2025.106108. Online ahead of print.
ABSTRACT
Infectious bursal disease (IBD) remains one of the most important immunosuppressive diseases in poultry and has been endemic in China for over four decades. In recent years, outbreaks characterized by markedly reduced mortality have emerged. To investigate the current prevalence and pathogenicity of infectious bursal disease virus (IBDV), strains were isolated from vaccinated poultry farms in central and eastern China, and representative isolates of distinct genotypes were evaluated for pathogenicity. Phylogenetic analysis of segment A (HVR) and segment B (B-marker) classified segment A into eight genogroups (A1-A8), with A2 further divided into A2.1 and A2.2 and A3 into six subtypes (A3.1-A3.6). Segment B was grouped into four genogroups (B1-B4), with B3 and B4 subdivided into B3.1-B3.4 and B4.1-B4.2, respectively. The 23 isolates obtained were grouped into three genotypes: A2.2B1 (14/23, 60.9 %), A3.2B3.2 (8/23, 34.8 %), and A3.5B3.3 (1/23, 4.3 %). The A2.2B1 and A3.5B3.3 strains showed only minor amino acid substitutions relative to reference strains, whereas the newly emerged A3.2B3.2 genotype displayed substantial divergence. Pathogenicity evaluation in SPF chickens revealed no mortality after infection with SD/23 (A3.2B3.2), SHX/24 (A3.5B3.3), or WD/22 (A2.2B1). However, all three strains significantly reduced the bursa-to-body weight index (BBIX) to below 0.7 at 5 days post-inoculation and caused severe bursal atrophy. Histopathological examination showed medullary necrosis and lymphocyte depletion in the bursa following infection with SD/23 and SHX/24, closely resembling the lesions induced by WD/22. Moreover, SD/23 and SHX/24 displayed replication dynamics similar to those of the reference strain LX (A3.1B2), with elevated viral detection rates and high viral loads in multiple organs. In summary, multiple IBDV genotypes are co-circulating in China. Despite the reduced pathogenicity of circulating strains, diminished attention to subclinical infections may facilitate viral transmission and cause considerable economic losses.
PMID:41270549 | PMC:PMC12677167 | DOI:10.1016/j.psj.2025.106108
Front Cell Infect Microbiol. 2025 Oct 17;15:1682969. doi: 10.3389/fcimb.2025.1682969. eCollection 2025.
ABSTRACT
Over the past few decades, battery industry and electronic equipment have undergone explosive growth, but the heavy metal waste generated has led to significant global ecological and public health challenges. Currently, increasing evidences have confirmed the detrimental effects of heavy metal exposure on animal reproduction, immunity, and metabolism. However, research focused on the impacts of battery leakage on the gut microbiota remain scarce. Thus, this study aims to investigate the detrimental effects of battery on gut microbiota in chickens. Results revealed that battery exposure can lead to a significant increase in spleen index and a significant decrease in thymus index in chickens. Furthermore, battery exposure can significantly increase serum ALT, AST and MDA levels, and while concurrently reducing levels of GSH-Px and SOD. Battery exposure also cause a significant reduction in the gut microbial alpha diversity, accompanied by significant alterations in taxonomic composition. Bacterial taxonomic analysis indicated that the relative abundances of 1 phyla and 4 genera increased dramatically, while the relative abundance of 3 phylum and 115 genera decreased significantly during battery exposure. In conclusion, this study suggests that battery exposure leads to gut microbial dysbiosis and affect antioxidant ability in chickens. The significant alterations of gut microbiota may represent one of the mechanisms through which battery exerts its intestinal and renal toxicity. Given the context of battery pollutant leakage and inadequate recycling supervision, this study contributes to providing impetus for environmental protection agencies and organizations worldwide to enhance the recycling of battery waste.
PMID:41181318 | PMC:PMC12575344 | DOI:10.3389/fcimb.2025.1682969
Environ Res. 2025 Dec 15;287:123162. doi: 10.1016/j.envres.2025.123162. Epub 2025 Oct 20.
ABSTRACT
Emerging pesticides exposure in companion animals remains understudied despite growing concern over environmental contamination and pet health. We quantified 24 emerging pesticides and their metabolites in serum samples from 60 pet dogs and cats in Wuhan, China, using a salting-out assisted acetonitrile extraction method coupled with HPLC-MS/MS. A total of 19 compounds were detected in cats and 16 in dogs, with cats exhibiting significantly higher total pesticide concentrations (median: 4.90 ng/mL) than dogs (3.02 ng/mL). Organophosphates (OPs), particularly chlorpyrifos as indicated by its metabolite 3,5,6-trichloro-2-pyridinol (TCPY), were the predominant pesticide class in dogs, whereas pyrethroids (PYRs) and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) were more abundant in cats. TCPY, 2,4-D and N-desmethyl acetamiprid (a neonicotinoid metabolite) were the most frequently detected pesticides across both species. Estimated daily intakes (EDIs) of these three dominant pesticides (0.0002-0.0649 μg/kg bw/day) were well below established chronic reference doses (cRfDs; 0.3-71 μg/kg bw/day), suggesting limited individual pesticide risk. However, over 95 % of serum samples contained multiple pesticide residues, raising concerns about potential cumulative and synergistic effect. These findings underscore the need for expanded biomonitoring efforts to better understand emerging pesticide exposure in pets and their role as sentinels for household and environmental chemical risks.
PMID:41125199 | DOI:10.1016/j.envres.2025.123162
Virus Evol. 2025 Sep 23;11(1):veaf075. doi: 10.1093/ve/veaf075. eCollection 2025.
ABSTRACT
Newcastle disease (ND), caused by virulent strains of avian paramyxovirus type-1 (APMV-1), is one of the most important poultry diseases globally due to its economic impact and endemicity in lower- and middle-income countries. A variant of APMV-1 is endemic in Columbiformes (pigeons and doves) worldwide and is commonly termed pigeon paramyxovirus-1 (PPMV-1). Since its initial detection in the 1980s, PPMV-1 has caused numerous ND outbreaks in poultry, including in high-income countries, and was the causative agent for the last ND outbreak in the British Isles in 2006. Here, we have undertaken sequencing of PPMV-1 isolates between 1983 and 2023 and define three distinct genotypes of PPMV-1 being present in the British Isles. Analysis of the contemporary VI.2.1.1.2.2 genotype, demonstrated likely incursion from mainland Europe, whilst this genotype has subsequently spread across China, with detections also occurring in Australia. The presence of a virulent fusion-gene cleavage site in sequences highlights the continued risk to poultry from PPMV-1 genotypes, which were detected in pigeons and doves across the British Isles.
PMID:41089326 | PMC:PMC12516948 | DOI:10.1093/ve/veaf075
Vaccine. 2025 Oct 24;65:127775. doi: 10.1016/j.vaccine.2025.127775. Epub 2025 Sep 25.
ABSTRACT
Influenza vaccination saves lives, reduces short-term and long-term health consequences, decreases healthcare utilization, and improves pregnancy outcomes and infant health. Consequently, many, although not all, high-income countries have influenza vaccination policies that recognize both the direct (prevention of infection) and indirect (e.g., reduction in transmission and absenteeism, exacerbations of other health conditions) benefits of vaccination. Vaccination policies for COVID-19 are less consistent, even though COVID-19 continues to cause more infections than influenza. Indeed, some countries recommend COVID-19 vaccination only for older adults and individuals who are severely immunocompromised. Herein we compare influenza and COVID-19 vaccination effectiveness against both acute infection and indirect effects of infection. We find that COVID-19 vaccines are equivalent to, or outperform, influenza vaccines when comparing protection from symptomatic infection, reduction in severe disease, safety profiles, and real-world effectiveness. We propose that expansion of COVID-19 vaccination policies would reduce disruptions to school, work, and healthcare systems, in addition to preventing hospitalizations and severe disease.
PMID:41004948 | DOI:10.1016/j.vaccine.2025.127775
Proc Natl Acad Sci U S A. 2025 Sep 16;122(37):e2423973122. doi: 10.1073/pnas.2423973122. Epub 2025 Sep 11.
ABSTRACT
Influenza A virus (IAV) infection causes significantly greater morbidity and mortality in the elderly population, but the molecular mechanisms in the aging process responsible for severe infection remain unclear. In this study, we found that increased severity in IAV infection and reduced innate immune response correlated with extensive mitophagy in senescent human cells and in the lung of aged mice. Apolipoprotein D (ApoD) was identified as strongly elevated in the lungs and sera of aged human (>65 y old) and mouse (>21 mo old). ApoD was able to localize to mitochondria and interact, through its WXXI motif in the LC3B-Interacting Region domain, with LC3B to trigger mitophagy during IAV infection, in a PINK1 pathway independent manner, which attenuated type I interferon response and promoted virus replication. ApoD deficiency, on the other hand, protected older mice from severe influenza and improved survival. Likewise, depletion of senescent cells by ABT-263, a senolytic compound, in aged mice lowered ApoD level and restored innate immune antiviral response, limiting virus propagation and associated pulmonary damage. Thus, age-induced ApoD drives IAV-mediated mitophagy, and promotes virus replication and infection severity, and is therefore a promising target for inhibition to improve disease outcome in older patients.
PMID:40932775 | PMC:PMC12452933 | DOI:10.1073/pnas.2423973122
J Virol. 2025 Oct 23;99(10):e0043025. doi: 10.1128/jvi.00430-25. Epub 2025 Sep 8.
ABSTRACT
Swine influenza A virus (swIAV) is an important zoonotic pathogen with the potential to cause human influenza pandemics. Swine are considered "mixing vessels" for generating novel reassortant influenza A viruses. In 2009, a swine-origin reassortant virus (2009 pandemic H1N1, pdm/09 H1N1) spilled over to humans, causing a global influenza pandemic. This virus soon spread back into swine herds and reassorted with the circulating swIAVs. We previously reported that the genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 virus, which bore pdm/09- and triple reassortant (TR)-derived internal genes, had been predominant in swine populations of China since 2016, posing a threat to both the swine industry and public health. Here, our ongoing surveillance confirmed that G4 EA H1N1 viruses remained the predominant swIAVs in China from 2019 to 2023 and had reassorted with the co-circulating swIAVs, such as the H3N2 virus, to generate novel reassortant EA H1N2 viruses. Genetic analyses revealed that the pdm/09-derived internal genes of G4 EA H1N1 viruses originated from reassortments between pdm/09 H1N1 and EA H1N1 viruses in 2009-2010 and underwent independent and continuous evolution in the swine host, exhibiting higher evolutionary rates than those of the pdm/09 H1N1 virus circulating in humans. The accelerated evolution of internal genes enhanced the polymerase activity of G4 EA H1N1 viruses in mammalian cells, resulting in increased viral replication and pathogenicity in mice. This study provides evidence for swine in promoting the genetic evolution of influenza A virus and highlights the need for increased attention to novel reassortant viruses in swine.IMPORTANCEThe emergence of pdm/09 H1N1 virus highlights the role of swine influenza A viruses (swIAVs) in generating novel influenza viruses with pandemic potential. Since 2009, the pdm/09 H1N1 virus has been frequently transmitted to swine and reassorted with the circulating swIAVs, generating many new reassortant viruses bearing pdm/09-derived genes globally. The G4 EA H1N1 viruses, which bore pdm/09-derived internal genes and acquired increased human infectivity, remained the predominant swIAVs in China from 2019 to 2023 and reassorted with the co-circulating swIAVs to generate novel subtype viruses. The internal genes of G4 EA H1N1 viruses originated from the human pdm/09 H1N1 viruses during 2009-2010 and exhibited higher evolutionary rates and greater genetic diversity than those in the human host. This has contributed to increased viral adaptation and pathogenicity in mammals. Therefore, sustained surveillance and immunization efforts are essential to control emerging reassortant swIAVs and protect public health.
PMID:40919902 | PMC:PMC12548388 | DOI:10.1128/jvi.00430-25
