Veterinary Research最新文献

Foot-and-mouth disease (FMD) remains endemic in Bangladesh with the persistent circulation of FMD virus (FMDV) serotypes O, A, and Asia 1, underscoring the need for robust epidemiological data to inform and optimize national FMD control strategies. This study analyzed 57 VP1 coding sequences obtained from 89 clinical samples collected from FMD-infected cattle in Bangladesh between 2021 and 2023. Phylogenetic analysis classified these field isolates into three FMDV lineages: O/ME-SA/Ind-2001e (n = 40, 70.2%), O/ME-SA/SA-2018 (n = 15, 26.3%), and A/ASIA/Iran-05 (n = 2, 3.5%). The O/ME-SA/SA-2018 lineage detected in 2022 (61.1%) and 2023 (25.0%) shared 94.24-99.06% nucleotide sequence identity with viruses from the same lineage collected in 2021. Sequences for O/ME-SA/SA-2018 were monophyletic, while data for O/ME-SA/Ind-2001e provided evidence for viruses evolving within two sister clades in Bangladesh during 2021-23. Additionally, two samples collected in 2023 and tested positive for serotype A were characterized as belonging to the A/ASIA/Iran-05 lineage (sublineage FAR-11), representing the first cases of this lineage reported within the FMD endemic Pool 2. Analyses showed that VP1 sequences for two isolates (A/BAN5/2023 and A/BAN6/2023) were most closely related to a virus isolated in Pakistan during 2022 (PAK/41/2022a), sharing 97.81% nucleotide identity and a common ancestor dated March 2022. Further studies are needed to identify likely pathways of introduction of the A/Iran-05 lineage in Bangladesh, as well as to assess the potential risk to neighboring countries. This study highlights the importance of continuous FMD monitoring in Bangladesh to inform both control and vaccination strategies.

Tuberculosis (TB) is a worldwide zoonotic disease caused by bacteria members of the Mycobacterium tuberculosis complex (MTC), which affects a wide range of domestic and wildlife species, as well as humans. TB is characterized as a chronic pulmonary infection, primarily affecting the lungs and local lymph nodes (LNs), causing significant respiratory and immunosuppression problems. MTC members have the capability to survive in the host by evading the immune system's killing mechanisms and persisting within macrophages. This chronic antigenic stimulation promotes the formation of a complex, organized tissue structure known as a tuberculous granuloma, which is a defining cellular response to mycobacteria infections, and is composed of a compact aggregate of immune cells, whose functions are modulated by cytokines. The immune response against TB is complex and nowadays is not completely understood; therefore, the study of its immunopathogenesis becomes essential for evaluating immune-mediated response against mycobacterial infections, and consequently, develop strategies to control and eradicate the propagation of this disease in animals and humans. The aim of this work was to review the literature on key cell populations and immunological markers involved in the formation and development of granulomas in the lungs of humans and animals, and to discuss their potential use in evaluating the efficacy of novel vaccine candidates ‒ a tool that could contribute to TB control.

Avian influenza viral ribonucleoproteins (vRNPs) complete genome transcription and replication by interacting with host proteins, and RNA-dependent RNA polymerase (RdRp) is its major component. PB2 is a component of RdRp and plays an important role in viral RNA synthesis. Our previous mass spectrometry analysis identified PB2 interacted with avian cellular heterogeneous nuclear ribonucleoprotein AB (hnRNP AB). However, the specific mechanism of this interaction regulating viral replication needs to be further clarified. In this study, we found that avian hnRNP AB inhibited the replication of multiple subtypes of avian influenza viruses (AIVs) from different reservoirs, and the glycine-rich domain (GRD) of hnRNP AB was the function domain that inhibited AIV replication. Moreover, we demonstrated that the GRD of avian hnRNP AB interacted with the C-terminus of PB2, reducing the binding of PB1 to PB2 and interfering with RdRp assembly. Based on the previous discovery that hnRNP AB affected the nucleoplasmic distribution of PB2 mRNA, we have further explored the mechanism here. Mechanically, hnRNP AB intervened in the nuclear export of PB2 mRNA by reducing the binding ability of UAP56, and decreased PB2 expression to interfere with RdRp formation and reduce vRNA synthesis, which in turn inhibited viral replication. Collectively, this study demonstrated that the avian host protein hnRNP AB inhibited AIV replication by blocking assembly of RdRp and vRNA synthesis, in which was associated with UAP56-mediated nuclear export of PB2 mRNA, providing a potential target for antiviral intervention.

Epizootic haemorrhagic disease virus serotype 8 (EHDV-8) is an emerging Culicoides-borne virus that was first detected in Europe in autumn 2022 in Italy and subsequently spread to Spain, Portugal and France. Despite its economic impact, little is known about its tissue distribution, persistence, and induction of immune responses in cattle. Therefore, we conducted an experimental infection study in groups of 3 cattle inoculated intradermally (ID; 10^6.2 or 10^5.2 TCID₅₀/animal) or subcutaneously (SC, 10^6.2 TCID₅₀/animal) with a Spanish EHDV-8 isolate. Viremia appeared at 3 days post-inoculation (dpi), peaked at 7-10 dpi, and persisted until the end of the study (21 dpi). Fever spiked at 8-9 dpi with a longer duration in the high-dose groups. No other clinical symptoms were noted, except in one animal from the SC high-dose group. This animal exhibited apathy, conjunctivitis, and swollen lymph nodes from 10 dpi onwards. At necropsy, lymph nodes and spleen contained higher viral loads than muscles, brain, and skin. The clinical animal displayed petechiae on the kidney with high viral loads (Ct value = 20), which was an outlier compared with all other organs tested. The virological data thus confirmed that blood, spleen and lymph nodes are the most suitable diagnostic samples. A strong humoral response (100% seroconversion) was observed in all the groups at 10 dpi. All the animals, except the one showing clinical signs, also exhibited a strong cellular immune response, with IFN-γ levels peaking at 5-7 dpi. In conclusion, this study demonstrated that the inoculation route and dose only minimally impacted viremia, viral spread and induced immune responses.

The small intestine, a part of the digestive system, absorbs nutrients and plays a role in immune protection against viruses that can disrupt its activity. Currently, to analyse these functions, studies rely on in vivo (animals) or in vitro (most often immortalized cell lines) experiments. However, these models have ethical and methodological concerns. Organoids, an ex vivo model, consisting of 3D self-organized cell complexes to recapitulate the cellular diversity, structure, and functionality of an evaluated organ, represent an alternative system. However, to infect organoids, the apical pole containing viral receptors, which are localized in the lumen of the 3D organoids, must be accessible. For this purpose, 2D organoids, corresponding to dissociated and plated 3D organoids, are typically used. This study aimed to characterize the robustness and fidelity of 3D and 2D organoids in terms of gene expression in jejunum tissue and the contribution of 2D organoids in comparison to those of swine testicular cells (ST cells) and piglet jejunums to decipher host-virus interactions with transmissible gastroenteritis virus (TGEV). Our study revealed that our culture and differentiation procedures enabled the production of 3D and 2D organoids that reproduced intestinal epithelial organization with high repeatability. Similar to infected piglets and ST cells, infected 2D organoids expressed genes involved in innate and antiviral immune responses, with a variety of genes activated as a function of viral load. Organoids, which maintain the cellular diversity of the intestinal epithelium, therefore offer the possibility to decipher the host-virus interactions involved in enteric infections.

Th17 cells play important roles in anti-infective responses. The 15 kDa excretory/secretory protein of Haemonchus contortus (HcES-15) has been identified as a promising immune-protective antigen against H. contortus infection capable of up-regulating IL-17, IL-4 and IL-10 production. To obtain the peptides that primarily induce the Th17 immune response, we amplified and expressed the peptides ES15-1, ES15-2 and ES15-3 from HcES-15. In vitro studies demonstrated that ES15-1 stimulated transcriptional activation of the STAT3/RORγt signaling pathway and induced IL-17 production in goat peripheral blood mononuclear cells (PBMCs). In vivo studies, flow cytometric analysis revealed that subcutaneous injection of PLGA-encapsulated ES15-1 peptide (PLGA-ES15-1, 50 μg) significantly enhanced Th17 cell differentiation in the spleens of BALB/c mouse. Consistent with these findings, ELISA quantification demonstrated that ES15-1 treatment significantly increased serum levels of pro-inflammatory cytokine (IL-17, IL-1, IL-6, and TNF-α). In goat immune protection studies, goats (n = 6) were subcutaneously immunized with 500 μg of PLGA-ES15-1 on days 0 and 14, followed by infection with H. contortus infective third-stage larvae (iL3s) 1 week post-second immunization. ES15-1 significantly enhanced serum levels of pro-inflammatory cytokines (IL-17, IL-1, IL-6, TNF-α). At autopsy, vaccinated goats exhibited 69.0% (p < 0.001) reduction of fecal egg counts (FEC) and 50.54% (p < 0.05) reduction of worm burdens versus controls. Our findings suggested that peptide ES15-1 enhanced Th17 responses through regulation of the STAT3/RORγt pathway, conferring a certain immune protection against H. contortus infection.

Neonatal calves predominantly rely on colostral IgG for the passive transfer of immunity; however, little is known about their intrinsic capacity for mucosal immunoglobulin production and the developmental changes associated with their growth. To elucidate the developmental trajectory of mucosal immunity, we investigated changes in mucosal immunoglobulin concentrations and the expression levels of genes involved in immunoglobulin production and secretion across different growth stages in calves. The results demonstrated that fecal IgG and IgM levels exhibited transient peaks at 1 week of age according to smooth spline analysis, followed by sharp decreases, whereas IgA levels remained relatively stable and became the predominant isotype after 4 weeks. Gene expression analysis and immunohistochemistry revealed the localized expression of immunoglobulins in the intestinal mucosa, particularly IgA, which gradually increased with calf growth. The secretion of IgA is also thought to be facilitated by the upregulated expression of PIGR, a gene encoding the IgA transporter whose expression levels increase with calf growth. In contrast, the levels of plasma cell-recruiting chemokines and their receptors were not increased. These results suggest an important role for IgA in the mucosal defense system of the calf intestine, indicating its pivotal function in maintaining gut health following the clearance of colostral IgG.

Since the emergence of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4 Goose/Guangdong lineage in Europe in 2014, an unprecedented outbreak occurred during the 2021-2022 epidemiological year, causing mass mortalities in wild birds, including birds of prey, but also increasingly affecting Charadriiformes, which has imposed substantial ecological and infection pressure at the wild-bird-poultry and avian-mammalian interface. Neurological signs have been associated with higher fatalities in birds but pathological examinations of natural cases, including viral distribution, are currently lacking. In this study, we have thoroughly assessed the histopathological lesions and antigen distribution by immunohistochemistry (IHC) from 115 PCR-positive wild birds that died naturally from HPAI, including Charadriiformes, birds of prey, gamebirds, waterfowl and captive wild birds. The commonest histological lesion was pancreatic necrosis followed by splenic necrosis, encephalitis or neuronal necrosis, myocardial necrosis or myocarditis, necrosis of the respiratory tract and hepatic necrosis. Overall, 96 birds tested positive by IHC in multiple organs and most of the viral antigen was detected in the brain followed by the respiratory tract, heart, pancreas and kidney. In the brain, viral antigen was most commonly detected in neurons, neuropil and endothelium. In conclusion, HPAI-associated mortality in different wild birds can be associated with multisystemic viral dissemination and tissue damage, with endothelial tropism being a key feature in neuroinvasion and disease pathogenesis.

Vaccination against Mycoplasma hyopneumoniae is still carried out worldwide, but unfortunately current commercial vaccines only provide partial protection. Therefore, two M. hyopneumoniae strains were genetically modified by transposon-mediated gene disruption of mmsA and mnuA, encoding methylmalonate semialdehyde dehydrogenase and membrane nuclease A, respectively. We investigated how immune responses elicited by these genetically modified M. hyopneumoniae strains protected pigs against challenge infection. An endotracheal single dose vaccination with genetically modified M. hyopneumoniae strain 1 (ΔmmsA) or 2 (ΔmnuA), or physiological saline solution (Control) was followed by challenge infection. Piglets from ΔmnuA had a higher respiratory disease score post-vaccination, but this group coughed significantly less after challenge. Significantly fewer DNA copies of the challenge strains were observed in broncho-alveolar lavage fluid (BAL) from ΔmnuA after challenge. Two weeks post-challenge, significantly more BAL IgG and BAL IgA was observed in ΔmnuA, but at euthanasia significantly more IgA and less pro-inflammatory cytokines were detected in BAL from both vaccinated groups. Furthermore, a significantly lower percentage of IFN-γ⁺ and TNF-α⁺IFN-γ⁺ CD8⁺ T cells was observed after administration of ΔmnuA. The percentage of IFN-γ⁺ CD8⁺ T cells was significantly lower in ΔmmsA at euthanasia. To conclude, the results of this exploratory study show that a single endotracheal administration of ΔmnuA resulted in coughing post-vaccination, but reduced clinical signs post-challenge and challenge strain DNA load in BAL. Therefore, a strain mutated in the mnuA gene might be an interesting mutant strain that could be promising as a potential live vaccine candidate strain as it can reduce M. hyopneumoniae infection burden under field conditions.

Pseudorabies virus (PRV) infection causes fatal encephalitis across various species, a condition known as pseudorabies encephalitis (PRE). However, the molecular mechanisms underlying PRE remain poorly understood. Long noncoding RNAs (lncRNAs) have emerged as important regulators of gene expression in neurological diseases and viral infections. This study explores genome-wide transcriptional alterations in a mouse model of PRV-induced encephalitis. The intranasal inoculation of mice with PRV induced severe encephalitis, characterized by high viral loads, significant inflammatory responses, and the onset of neurological symptoms. RNA-seq analysis revealed 683 differentially expressed (DE) mRNAs and 179 DElncRNAs in PRV-infected brains compared with controls. Functional and pathway analyses revealed that PRE involves neurodegeneration and diverse immune responses, reflecting the complex interplay between viral evasion strategies and host defenses. Co-expression network analysis, supported by experimental validation, identified several lncRNAs as central hubs interacting with multiple immune-related genes and exhibiting cell type-specific expression pattern. Notably, ZFAS1 was prominently dysregulated in PRV-infected microglia and showed extensive co-expression connectivity. Knockdown of ZFAS1 modulated microglia-driven inflammation without altering viral replication, underscoring its potential as a therapeutic target for mitigating neuroinflammation in virus-associated neurological diseases. The identification of key lncRNAs and their potential regulatory roles deepens our understanding of disease mechanisms, while offering new avenues for therapeutic intervention in neurotropic viral infections.