Encephalomyocarditis virus (EMCV), a potential zoonotic pathogen, poses significant socioeconomic and public health challenges across various host species. Although EMCV rarely triggers severe clinical symptoms in humans, its widespread prevalence and unique biological characteristics underscore the need for continuous surveillance and the development of effective therapeutics and prophylactics. In this study, we evaluated the neutralizing effects of a monoclonal antibody derived from the spleens of mice immunized with EMCV virus-like particles (VLPs), both in vitro and in vivo. Using recombinant DNA technology, we engineered a baculovirus system to express EMCVs P12A and 3C, facilitating the production of VLPs in Sf9 cells. These VLPs serve as antigens to immunize mice, leading to the isolation of the monoclonal antibody 45G3. This antibody exhibited high specificity for EMCV conformational epitopes, excluding linear epitopes, and demonstrated potent in vitro neutralizing activity, with an IC50 of 0.01873 μg/mL. Immunoelectron microscopy (IEM) revealed a strong direct interaction between the 45G3 antibody and EMCV particles. Virus adsorption inhibition assays demonstrated that 45G3 effectively blocked viral attachment, thereby preventing further infection of host cells. These findings further support the notion of a robust interaction between the virus and the antibody. Moreover, in vivo assessments revealed that 45G3 significantly reduced viral loads in treated mice and improved survival outcomes following EMCV exposure. Additionally, posttreatment analysis revealed reduced tissue damage and a markedly decreased inflammatory response in the brain, indicating that the 45G3 antibody effectively blocked viral infection, thereby mitigating tissue damage and enhancing survival. These findings position 45G3 as a promising candidate for EMCV management and provide a strong foundation for the future development of antiviral drugs targeting this widespread virus.

Porcine deltacoronavirus (PDCoV) is a globally distributed swine enteropathogenic virus that emerged in the last decade. A recent report of PDCoV infection in Haitian children also highlights potential public health implications. In this study, two monoclonal antibodies (mAbs), 1C2 and 5H5, were generated and showed high specificity for the PDCoV S protein. Both mAbs displayed high-titer neutralizing capabilities, suggesting their potential for passive immunotherapy. Epitope mapping revealed that the mAbs likely recognized conformational epitopes in the S1 subunit domains A and B of the native S protein, thereby blocking the interaction between the S1 receptor-binding domain and the cellular receptor, which could inhibit viral entry into host cells. This study offers new biological tools for PDCoV detection and lays the groundwork for the future development of porcine-specific antibodies for the prevention and treatment of PDCoV in piglets.

Pseudorabies virus (PRV, SuidAlphaherpesvirus 1) causes substantial economic losses in swine production. Here, we report the development of DNA aptamers targeting the PRV glycoprotein D (gD) through an optimized SELEX protocol. After 15 selection cycles, Apt-gD-2 demonstrated nanomolar affinity (Kd = 6.107 ± 0.476 nM) and high specificity for gD, as validated by an enzyme-linked aptamer-sorbent assay (ELASA) and fluorescence microscopy. Molecular docking revealed hydrogen bonding as the key interaction mechanism. The developed ic-ELASA achieved 83.3% concordance with qPCR in clinical samples, supporting its utility for on-farm PRV surveillance. These findings highlight the potential of aptamer-based diagnostic methods for rapid, sensitive, and onsite detection of PRV, offering a promising tool for disease control in the swine industry.

Feline injection site sarcomas (FISSs) are tumors frequently found at injection sites in domestic cats associated with vaccines and other pharmaceutical substances. The most accepted theory suggests that chronic inflammatory reactions at the injection site trigger these tumors. This study analyzed 58 cases of FISS in cats to investigate the role of tumor-associated macrophages (TAMs). Immunohistochemistry for MAC387+ macrophages was performed via the Novolink™ polymer detection system. TAMs were quantified and categorized into low, moderate, and extensive infiltration groups. Most tumors showed sparse macrophage infiltration (29 out of 58 cases), with moderate macrophage infiltration (18 out of 58), and 11 cases out of 58 showed high infiltration. Significant associations were found between TAM infiltration and the degree of differentiation (p<0.001), degree of necrosis (p=0.033), mitotic index (p= 0.003), and histological degree of malignancy (p<0.001). This study revealed that TAM density is correlated with tumor aggressiveness in the FISS, suggesting a fundamental role for macrophages in the tumor microenvironment and a promising marker for prognosis.

This report describes the first documented case of Mycobacterium caprae (M. caprae) infection in a domestic cat (Felis catus) in the United Kingdom. The affected cat was a male-castrated Bengal breed that presented with respiratory symptoms and progressive weight loss. Clinical signs were unresponsive to antibiotics and anti-inflammatory therapy. Postmortem examination and histopathology revealed severe chronic pyogranulomatous bronchopneumonia with necrosis and acid-fast bacilli, which were identified as M. capraevia PCR and culture. While primarily a pathogen of goats, M. caprae poses zoonotic risks and requires specialized diagnostics. This case emphasizes the need for interdisciplinary collaboration to address emerging zoonotic threats.

Coinfection, the simultaneous invasion of multiple pathogens into a single host, is a critical but understudied area, especially in the farm animal sector. We report a unique and unusual fatal case of coinfection with S. Indiana and S. Kentucky, which has rarely been studied in the literature and could hold potential importance for veterinary clinics. In silico analysis revealed that all the isolates exhibited extensive multidrug resistance. By analyzing the plasmids, two replicons, IncHI2 and IncHI2A, were detected in S. Indiana, whereas no plasmids were detected in S. Kentucky. Chicken embryo lethality assays demonstrated that both S. Indiana and S. Kentucky caused 100% mortality by the third day post infection, significantly exceeding the lethality of the control strains. These findings emphasize the high pathogenic potential of these serovars, especially S. Indiana, which carries the cdtB gene encoding typhoid toxin, further confirming its increased pathogenicity. Overall, our results underscore the urgent need to improve biosecurity measures to mitigate the risk of coinfections involving multidrug-resistant Salmonella strains in poultry production environments.

Peptide-based therapies have emerged as groundbreaking advancements in both therapeutic and preventive strategies against infectious diseases. These approaches utilize innovative functional immunopeptides—such as antigenic peptides, antimicrobial, immune modulation, and delivery peptides derived from pathogens or hosts—to target specific immune mechanisms. In addition to their simplicity of use, peptide-based approaches provide several advantages. These include improved specificity and immunogenicity by targeting specific antigenic peptides and enhanced delivery of particular proteins or vaccines to targeted immune cells, which increases the efficiency of antigen presentation and provides a self-adjuvant effect and therapeutic properties. The most recent developments in peptide-based systems to increase vaccine efficacy and therapeutic interventions for animal diseases are investigated in this review. It encompasses fundamental ideas, immunomodulating functions, and peptide production techniques. Additionally, the improvements and synergistic advantages attained by combining these functional immunopeptides with vaccines or using them as stand-alone therapeutic agents are emphasized. This review demonstrates how peptide-based treatments in veterinary medicine enhance immune responses and inhibit or eliminate pathogens.

Streptococcus suis (S. suis) is a major zoonotic pathogen whose nasopharyngeal colonization relies on adaptive regulation in response to the host’s low-glucose microenvironment. However, the molecular mechanisms underlying this adaptation remain largely unexplored. In this study, RNA-seq analysis of S. suis cultured under low-glucose (0.2%) conditions revealed 86 DEGs, predominantly associated with the phosphotransferase system, alternative carbon metabolism, and energy homeostasis pathways. A phenotypic screening of eight transcription factor (TF) mutants revealed that deletion of HrcA significantly impaired bacterial growth and survival under low-glucose conditions. ChIP-seq analysis revealed the HrcA-binding motif (GTGCTAATT) and mapped 391 potential target genes, 18 of which were differentially expressed under low-glucose conditions. Further qPCR and electrophoretic mobility shift assays (EMSAs) validated the direct regulation of 10 target genes by HrcA. Specifically, HrcA represses energy-intensive genes (B9H01_00980 and B9H01_04980) to conserve energy while activating B9H01_00995 and B9H01_01125 to promote alternative carbon metabolism and pyruvate fermentation. Additionally, HrcA modulates the expression of the AraC family TF1 and the DeoR family TF4, establishing a hierarchical regulatory network. Notably, HrcA downregulates its own expression under low-glucose conditions to fine-tune carbon metabolism gene regulation and maintain S. suis homeostasis, providing new insights into its adaptive strategies.

As a widely recognized environmental pollutant, Cr (VI) (hexavalent chromium) is a toxin that triggers carcinogenesis in poultry, particularly through oxidative damage. A new selenium variant, nanoselenium, has shown promise in mitigating heavy metal-induced toxicity. While most research on Cr (VI) toxicity has focused on broilers, the effects on laying hens remain underexplored. This study investigated the therapeutic potential of nanoselenium in alleviating Cr (VI)-induced toxicity in laying hens both in vivo and in vitro. Specifically, the mechanisms underlying chromium-induced cardiac damage and the protective effects of nanoselenium were examined. In vivo, exposure to Cr (VI) led to significant oxidative damage, autophagy, and apoptosis in myocardial cells, which was mediated by dysregulation of the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR signaling pathways and manifested as changes in reactive oxygen species (ROS) and matrix metalloproteinase (MMP) levels. Nanoselenium treatment effectively counteracted these effects, restoring pathway balance and reducing oxidative damage and mitochondrial dysfunction. Similarly, in vitro, nanoselenium reduces oxidative damage, and Cr (VI) initiates apoptosis in cardiac myocytes. These findings revealed that nanoselenium antagonizes chromium-induced cardiac toxicity in laying hens.

Porcine epidemic diarrhea virus (PEDV), an enteropathogenic coronavirus of significant veterinary importance, induces severe watery diarrhea and dehydration in swine populations, with mortality rates approaching 100% in neonatal piglets. Among PEDV variants, S-INDEL strains have drawn increasing attention because of their genetic divergence and uncertain pathogenic potential in the field. In 2024, a novel S-INDEL PEDV strain, designated PEDV CH/JSHA2024, was isolated from intestinal samples of diarrheic piglets on a commercial swine farm in Jiangsu Province, China. Recombination analysis revealed that the spike (S) glycoprotein gene of this strain originated from genetic recombination between the Ch/HNLH/2015 and SQ2014 progenitor strains. Comparative genomic analysis with the prototype OH851 strain revealed multiple amino acid substitutions and insertions, including multiple amino acid substitutions and insertions within the S1 subunit, along with the absence of a conserved N-glycosylation site at position 114 (N114). The pathogenic potential of PEDV CH/JSHA2024 was assessed in pigs of different ages and maternal antibody levels. The strain caused 100% mortality in 1-day-old piglets (6/6), 50% mortality in 3-day-old piglets lacking maternal antibodies (3/6), and no mortality in 3-day-old piglets with maternal antibodies (0/6). In older animals, including 4-week-old weaned piglets and gilts, infection led to acute diarrhea and reduced feed intake but not fatality. Notably, high levels of serum IgA antibodies persisted for at least two months postinfection. These findings advance our understanding of coronavirus evolution through genetic recombination events. The establishment of this experimental model provides a valuable platform for elucidating the molecular determinants underlying S-INDEL strain pathogenesis, with particular implications for vaccine development and herd immunity strategies.

In this study, we developed a highly sensitive enzyme-linked immunosorbent assay (ELISA) using newly produced monoclonal antibodies (mAbs) for detecting horse/donkey IL-1β in cell culture medium and serum samples. The mAbs were generated via the use of a KLH-conjugated peptide and purified equine IL-1β protein as separate immunogens. Notably, the generated mAbs (3G8 and 5G3) demonstrated no cross-reactivity with other major inflammatory mediators, including IL-1α, IL-1Ra, TNF-α, and SAA. The IL-1β assay, which is based on the screened mAbs, exhibits a detection range of 200–10,000 pg/mL, meeting clinical detection requirements. The coefficients of variation for the repeatability and reproducibility of the assay were both less than 5%, indicating an acceptable level of variation. Subsequently, 84 equine and 24 asinine serum samples were collected, and the IL-1β concentration was measured with both our assay and a commercial kit in parallel. Our results revealed no significant difference between the in-house and commercial ELISA kits for the detection of IL-1β concentrations in horse sera. Moreover, our ELISA method demonstrated superior sensitivity for IL-1β detection in donkey samples compared to existing commercial assays. These findings suggest that the newly developed ELISA provides a reliable analytical method for detecting IL-1β in both equine and asinine samples.

Intestinal spirochetes are detected in a wide range of mammalian and avian host species. and cause enteric disease, especially in swine and poultry. Although avian intestinal spirocheosis (AIS) is considered a growing and underestimated problem in poultry production systems, its occurrence and economic burden cannot be neglected. The causative agent of AIS is Brachyspira spp., particularly Brachyspira pilosicoli (B. pilosicoli), B. intermedia, and B. alvinipulli. They are Gram-negative spiral motile, oxygen-tolerant, and fastidious slow-growing anaerobes of the order Spirochaetes. The bacterium colonizes the lower gastrointestinal tract of most domestic and free-living birds. Layer and breeder chickens are most susceptible to Brachyspira spp. infection and present signs of chronic diarrhea, a low growth rate, delayed or reduced egg production, and poor egg quality. The zoonotic potential of B. pilosicoli is increasingly recognized. Humans can become infected via contact with the feces or meat of infected animals or food contaminated by food handlers. Patients with colonic spirochaetosis exhibit signs of diarrhea, rectal bleeding, and abdominal pain. Diagnosis is usually carried out through conventional isolation and identification as well as recent molecular detection techniques. Tiamulin and other macrolides are considered the gold standard for treating AIS. Unfortunately, resistance of bacteria to such treatments has emerged owing to the urgent need for the development of new interventions. Non-antibiotic interventions such as probiotics show promising results in preventing Brachyspira infection. There are no commercially available vaccines to prevent AIS. However, a recombinant vaccine against B. pilosicoli was recently developed in layer chickens. Here, the review discusses AIS in terms of etiology and pathogenesis, susceptibility and transmission, clinical picture in poultry, human infection, laboratory diagnosis, and prevention and treatment.

Lumpy skin disease (LSD) has caused economic losses in cattle, and Thailand experienced a nationwide outbreak in 2021. Spatial epidemiology plays a crucial role in identifying transmission patterns and high-risk areas for targeted disease control. This study examines the spatial epidemiology of LSD by analyzing clustering patterns, disease hotspots, and the directional spread of outbreaks in dairy farm networks with short interfarm proximities. LSD outbreak data from a large dairy farming area in northern Thailand were analyzed via multiple spatial analytical techniques. The standard deviation ellipse (SDE) approach, implemented with the Yuill and CrimeStat methods, was employed to determine the spatial-directional spread of outbreaks. Global and local Moran’s I statistics were used to assess spatial autocorrelation, whereas kernel density estimation (KDE) was used to identify the density areas of the LSD outbreaks. Ordinary kriging was applied to interpolate high-intensity surfaces. The results from the SDE indicate that the LSD outbreaks predominantly followed a northeast-to-southwest trend. Global Moran’s I revealed no statistical significance, whereas local Moran’s I indicated significant local spatial autocorrelation. KDE revealed a high density of outbreaks in the upper northern part of the farming region. Additionally, ordinary kriging was used to quantify the likelihood of outbreaks across different areas, highlighting potential high-intensity surfaces. These results enhance the understanding of LSD spatial epidemiology, providing valuable insights into disease dynamics and transmission. Additionally, these findings support policymakers in making informed decisions on targeted prevention, control strategies, and resource allocation at the local and regional levels.

Brucella, the causative agent of brucellosis, is a globally significant zoonotic pathogen with serious public health implications. Understanding the molecular and genetic characteristics of Brucella species is crucial for the precise prevention, control, and epidemiological traceback investigation of brucellosis. In this study, 82 Brucella strains were genotyped via multiple-locus variable-number tandem-repeat analysis (MLVA-11) and multilocus sequence typing (MLST-21). Among these strains, four species and 14 biotypes were identified. MLVA-11 analysis revealed that 82 strains of bacteria contained 25 MLVA-11 genotypes, with genotype 72 (N = 10) and genotype 116 (N = 10) being the dominant genotypes. Hunter & Gaston diversity index (HGDI) analysis was conducted on the repeat results of 11 VNTR loci across all strains. These 11 VNTR loci exhibited varying degrees of polymorphism, with four loci demonstrating high levels of polymorphism. Notably, the 18 loci presented the highest degree of polymorphism, with a polymorphism index reaching 0.712. MLST-21 analysis revealed that 82 strains of Brucella contained 16 genotypes, with ST-8 (N = 33) being the dominant genotype. This study elucidates the phylogenetic relationships among diverse Brucella species. A comparison of the clustering results for 82 Brucella strains obtained via the two methods revealed that the MLVA-11 typing results more reliably encompassed the typing information provided by MLST-21. These findings provide novel insights into the molecular epidemiology of Brucella, which may facilitate the development of more effective strategies for brucellosis prevention and control.

Lumpy skin disease (LSD) is a highly contagious viral disease in cattle caused by lumpy skin disease virus (LSDV), which belongs to the genus Capripoxvirus (CaPVs) within the family Poxviridae. Since its first outbreak in China in August 2019, LSD has spread widely across mainland China, posing significant threats to the cattle industry. This study aimed to isolate and identify a clinical strain of LSDV via Vero cells. Skin tissue samples from lump lesions were homogenized and inoculated onto cell cultures. After 7 passages, the inoculated cells exhibited typical cytopathic effects (CPEs). PCR amplification of the LSDV132 gene confirmed the presence of LSDV nucleic acid. In addition, quantitative PCR (qPCR) demonstrated a significant increase in viral copy number over time. Transmission electron microscopy (TEM) revealed typical brick-shaped viral particles. Furthermore, an indirect immunofluorescence assay (IFA) of infected Vero cells exhibiting CPEs produced a positive reaction with antiserum from cattle naturally infected with LSDV. Additionally, nucleotide similarity analysis of 123 LSDV strains revealed a high degree of similarity (98.4%-100%) among different geographic lineages. Nucleotide sequencing and recombination analysis of the LSDV011 gene from LSDV/China/HB01/2020 revealed close similarity to Asian strains and revealed a recombination event. Furthermore, similarity plot analysis confirmed two genomic exchange sites at nucleotide positions 120 and 762 within the LSDV011 gene. Recombination events between 65 Asian LSDV strains and 13 goatpox virus (GTPV) strains have raised safety concerns regarding the use of attenuated goatpox vaccines, highlighting the need for novel and safer LSDV vaccines. In summary, this study successfully isolated a clinical LSDV strain, demonstrating its evolutionary status and providing crucial insights for LSD control in the cattle industry.

Toxoplasma gondii (T. gondii) is a globally distributed parasite that can infect a diversity of warm-blooded animals, including swine and humans. Infection in swine poses a considerable threat to food safety and public health. The aim of this meta-analysis was to estimate the seroprevalence of T. gondii infection in the swine population in China from 2000 to 2023 and to examine potential factors associated with infection. A total of 112 studies were included, collectively involving 145,152 swine samples originating from 26 provinces. The pooled seroprevalence was 26.0% (95% CI: 23.3%–28.7%). Stratified analysis based on diagnostic methods revealed that studies using the indirect hemagglutination assay (IHA) reported a seroprevalence of 19.7% (95% CI: 17.2%–22.2%), whereas those utilizing the enzyme-linked immunosorbent assay (ELISA) reported a higher seroprevalence of 35.5% (95% CI: 29.1%–41.8%). Geographical analysis indicated higher seroprevalence in the South Central and Southwest regions, whereas the East and Northwest areas reported the lowest seroprevalence. Chongqing Province reported the highest seroprevalence, reaching 44.9% (95% CI: 43.4%–46.0%), followed by Xinjiang, Hainan, and Guizhou, whereas the lowest was observed in Shandong Province (3.5%, 95% CI: 1.7%–6.1%). These findings provide important epidemiological evidence that can inform strategies for the prevention and control of T. gondii infection in swine populations, with a focus on high-risk populations and geographical areas. This imperative contributes substantially to the improvement of both food safety and public health.

Porcine rotavirus (PoRV) is widely prevalent in Chinese pig farms and causes substantial economic losses to the swine industry. Virus isolation remains technically challenging, and the pathogenicity of circulating strains in piglets is incompletely characterized. A total of 481 diarrhoeic samples were collected from Anhui province, China. PoRV was detected on 83.33% (15/18) of the farms, with a sample-level positivity rate of 28.48% (137/481). Phylogenetic analysis of the VP7 and VP4 genes identified G9 (50.00%) and P[23] (13.33%) as the predominant genotypes. A PoRV strain was successfully isolated and named RVA/Pig/China/GL/2022/G9P[23] (GL/2022), exhibiting a genomic constellation of G9–P[23]–I5–R1–C1–M1–A8–N1–T1–E1–H1. Comparative phylogenetic analyses revealed that GL/2022 shares high homology with both human and porcine RVA lineages, indicating possible interspecies reassortment. Importantly, this study represents the first systematic comparison of the evolutionary dynamics of GL/2022 with those of previously reported G9P[23] strains. Pathogenicity experiments demonstrated that GL/2022 induced severe enteric lesions and 50% mortality in neonatal piglets. These findings highlight PoRV's genetic complexity and zoonotic potential, providing critical insights for disease surveillance and vaccine development.

Hepatitis, caused by five main viral strains (A, B, C, D, and E), is a major global health issue in animals and humans. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are particularly concerning and can lead to chronic diseases, cirrhosis, liver cancer, and death. Recent WHO data indicate a rise in hepatitis-related deaths from 1.1 million (2019) to 1.3 million (2022), predominantly attributed to HBV. China bears a substantial global burden of HBV and HCV due to its large population. Data on hepatitis A, B, C, E, and unclassified hepatitis from 2004–2019 were obtained from the Chinese Center for Disease Control and Prevention. Joinpoint, ArcGIS, and SaTScan were used to analyze trends, spatial‒temporal distributions, and correlations. From 2004–2019, the overall incidence and mortality of viral hepatitis in China declined. Although hepatitis C and E showed an initial increase until 2012 before stabilizing. Hepatitis B remains the most common strain, with peaks in spring, particularly in the southeastern provinces (Jiangsu, Zhejiang, Fujian). Farmers and workers were the most affected groups due to their living and hygiene conditions. Spatial analysis revealed higher concentrations of cases in rapidly urbanizing and mobile regions. Enhanced prevention and control strategies targeting high-risk populations and regions are critical for reducing hepatitis transmission and improving public health in China.

The original online version of this article was revised: Equal contribution statement has been added. Figure 1, Figure 2, Figure 7, and Figure 8 have been updated. Figure 1, Figure 2, and Figure 3 captions have been updated.

A correction to this article is available online at https://doi.org/10.1186/s44149-025-00192-9.

Zoonotic cryptosporidiosis is caused primarily by Cryptosporidium parvum. Within C. parvum, the IIa and IId zoonotic subtype families are the most prevalent. The IId subtype family has emerged in China in recent years, causing outbreaks of cryptosporidiosis in dairy calves. The majority of infection studies have been conducted with IIa subtypes, while the pathogenicity of IId subtypes remains poorly understood. In this study, two IId isolates (IIdA20G1-HLJ and IIdA20G1-HB) from dairy farms in China were used to infect neonatal dairy calves, with a IIa isolate (IIaA17G2R1-Waterborne) from the USA employed as a control. The present study investigated the clinical, parasitological, and pathological characteristics of infected calves. The results demonstrated significantly greater intensity and duration of oocyst shedding in IId-infected calves than in control calves. In addition, the IIdA20G1-HLJ isolate induced peak oocyst shedding of 4.3×10⁷ oocysts per gram of feces (OPG) in calves, with oocyst shedding over 10⁶ OPGs at 5–9 d post-infection. In contrast, the IIaA17G2R1-Waterbrone isolate induced a lower peak oocyst shedding with 8.7×10⁶ OPGs, and oocyst shedding with over 10⁶ OPGs occurred at 2–4 d post-infection. Furthermore, calves infected with the two IId isolates presented more severe clinical signs and 20–25% mortality. Calves recovered from the primary infection with the IIa or IId subtype were resistant to a secondary challenge with the heterologous subtype, suggesting the existence of cross-protection between the IIa and IId subtypes. The present data demonstrate the high pathogenicity of C. parvum IId subtypes in China and the potential cross-protective immunity between the IIa and IId subtypes in calves.

Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic coronavirus that currently poses significant threats to the global swine industry. The spike (S) protein is the main PEDV structural protein that mediates viral entry while also serving as the major antigen that triggers host immune responses. To aid in the development of novel, advanced antiviral intervention strategies, identification of conserved epitopes within the fast-evolving S protein is essential. In the present study, we generated seven monoclonal antibodies (mAbs) against the S protein via the use of purified PEDV virions as immunogens, namely, 1F11, 2C4, 3D11, 3G7, 4G5, 8B2, and 8E4. Most of them were demonstrated to recognize conformational epitopes of the S protein, whereas only 4G5 was shown to recognize a linear epitope. To this end, a novel B-cell epitope, ¹²⁷³NATYLNLTGE¹²⁸², was identified and further shown to be highly conserved among different PEDV isolates. Taken together, our study contributes to a better understanding of PEDV S antigenicity, as the identification and validation of this conserved epitope will provide support for the development of serological diagnostic tools.

African swine fever (ASF) is a devastating disease of pigs, and control measures are needed worldwide. This review examines advances in the in vitro culture and propagation of ASF virus (ASFV), which are essential for the development of ASF vaccines. As conventional ASFV culture in primary porcine macrophages is challenging in terms of scalability, cost, and biosafety, increasing research has focused on the adaptation of ASFV to different systems, particularly nonporcine or stable porcine cell lines. This adaptation process, which may include serial passaging, results in genetic changes and attenuation in pigs, an important feature for the production of live attenuated vaccines (LAVs). Modern biotechnological tools such as synthetic genomics and reverse genetics have accelerated the development of ASFV strains with specific, advantageous traits. However, a major problem with LAV candidates generated by cell culture adaptation is the possible return to virulence in pigs after back-passage in vivo, which requires careful safety assessment. Nonetheless, the use of continuous cell lines offers a viable route for economical, large-scale ASF vaccine production. Future research should focus on identifying vaccine candidates that offer broad protection and exceptional safety, with an emphasis on cross-protection against different ASFV strains, while ensuring the economic viability of innovative production methods.

Streptococcus suis (S. suis) is an important zoonotic pathogen that can cause sepsis, meningitis and toxic shock syndrome and is a serious threat to public health. Conventional antibiotic therapy is facing an increasing problem of drug resistance, and antivirulence strategies targeting virulence factors provide a new direction for infection prevention and control. Natural products provide potential lead compounds for the development of novel antibacterial drugs. Suilysin (SLY), a key virulence factor, plays a key role in pathogenesis by disrupting host cell membranes, inducing excessive inflammatory responses and promoting blood‒brain barrier penetration. In this paper, we systematically review the progress of research on antivirulence natural products that target SLY, including flavonoids, bioflavonoids, flavonols, flavonolignans, isoflavonoids and alkaloids. These natural products can directly target SLY; combine antibacterial, anti-inflammatory and antioxidant effects; and are less likely to induce drug resistance. This review provides data support and references for the development of novel natural antimicrobial drugs and anti-infection strategies.

Porcine epidemic diarrhea virus (PEDV) is a significant pathogen that causes severe diarrhea and high mortality rates in piglets. Thus, maternal and lactogenic immunity is a key success in protecting piglets from PEDV. Here, we developed four recombinant adenovirus (rAd)-based vaccine candidates against PEDV harboring novel immunogens fused with mucosal adjuvants and evaluated their capacity to elicit maternal and lactogenic immunity in gestating sows. The rAd-based vaccines were developed on the basis of the new immunogen PEDVSME (rAd. PEDVSME) and its derivatives fused with three mucosal adjuvants: bacterial outer membrane protein H (OmpH), cholera toxin B subunit (CTB), and GM-CSF/IL-4 fusion protein (GI). In a randomized controlled trial, a total of 50 pregnant sows (n = 10/group) received a prime-boost vaccination regimen of rAd. PEDVSME, rAd. PEDVSME-OmpH, rAd. PEDVSME-CTB, rAd. PEDVSME-GI and PBS were used as controls. After the second dose, the rAd. PEDVSME-CTB induced the highest PEDV-specific IgG response with the highest PEDV-neutralizing titer in pregnant sows, whereas rAd. PEDVSME-OmpH elicited the greatest level of systemic PEDV-specific IgA responses. For the transfer of maternal PEDV-specific antibodies into colostrum, all three rAd-based vaccines expressing adjuvanted immunogens (PEDVSME-OmpH, PEDVSME-CTB, PEDVSME-GI) were superior to the rAd expressing the original immunogen PEDVSME and the PBS control. Interestingly, IgG was the dominant isotype in colostrum, and correlated more strongly with neutralizing activity than IgA. In offspring, newborn piglets from all four groups of sows receiving rAd-based vaccines had antibodies with neutralizing titers higher than those from the control group. During the weaning period, decreases in neutralizing titers were observed in all groups, except for piglets from the rAd group. PEDVSME-OmpH group, whose neutralizing titers were well maintained and significantly greater than those in the control group (P<0.05). These findings demonstrate that the rAd-based vaccines expressing the PEDVSME immunogen fused with the mucosal adjuvant OmpH (rAd. PEDVSME-OmpH) are primary candidates for further evaluation viral challenge in piglets to determine their protective efficacy via passively lactogenic immunity.

Sacbrood virus (SBV) is one of the most pathogenic honeybee viruses with host specificity and regional variation. The SBV strain infecting the Chinese honeybee (Apis cerana) is known as Chinese sacbrood virus (CSBV). The extensively used CSBV detection methods require professionals and expensive equipment; thus, they are unsuitable for rapid onsite CSBV detection. To achieve early and rapid detection of CSBV, we developed a lateral flow detection (LFD) strip method for CSBV detection via clustered regularly interspaced short palindromic repeats (CRISPR) and the Cas13a technique. On the basis of the conserved CSBV VP2 gene nucleotide region, we designed 3 recombinant enzyme-assisted amplification (RAA) primer pairs and prepared 3 corresponding crRNAs. We investigated key performance metrics, including the sensitivity, specificity, and accuracy of LFD strips. The results demonstrated that the LFD strip based on the optimal combination (primer 2+crRNA 2) presented the lowest detection limit (2.80×10¹ copies/μL), and this strip could complete CSBV detection within 1 h. Furthermore, this strip exhibited excellent detection specificity, with no cross-reactivity with four other honeybee viruses. A test of 100 clinical samples indicated the feasibility of the LFD method for CSBV detection. A comparison of various CSBV detection methods revealed that the CRISPR-Cas13a-based LFD method was more accurate, efficient, and sensitive than the other methods were, indicating great application prospects in onsite CSBV detection. Our developed method is highly important for preventing and controlling CSBV infection as well as maintaining honeybee health.

Bacillus velezensis (B. velezensis) is a new generation of probiotics that has excellent benefits, bacteriostatic activity, and growth-promoting activity. In this study, a novel B. velezensis strain, B. velezensis XJC-1, was isolated from healthy cats in Xinjiang. This strain exhibited a certain tolerance to acidic conditions (pH 3.0 for 6 h), bile salts (0.1% and 0.3% for 6 h), and high temperatures (50°C, 60°C and 70°C for 10 min). Whole-genome sequencing (WGS) revealed that XJC-1 (GenBank Accession: JBPEKN000000000) yielded a total of 36 scaffolds, encompassing 3,916,364 base pairs (bp) in total, with an average G+C content of 46.31%. UniProtKB/Swiss-Prot annotates stress resistance genes, such as dnaK, which aligns with the observed phenotypic traits. AntiSMASH-7.1.0 identified 20 secondary metabolite clusters, especially six 100% similar biosynthesis-related gene clusters (bacillaene, bacilysin, bacinapeptin, bacillibactin, bacillothiazols A-N and macrolactin H), which are correlated with the inhibitory effects against Escherichia coli, Staphylococcus aureus and Salmonella enteritidis. In the safety evaluation, XJC-1 was sensitive to 8 antibiotics, and in silico polymerase chain reaction (PCR) screening revealed that there were no common enterotoxin-related genes in the genome of XJC-1. In addition, there were no acquired drug resistance genes or common food-borne bacterial virulence genes in its genome. Critically, gas chromatography–mass spectrometry (GC–MS) analysis revealed that XJC-1 produced short-chain fatty acids (SCFAs), with acetic acid being the major component (418 mg/L), which was consistent with the metabolism of cofactors/vitamins pathway in the Kyoto Encyclopedia of Genes and Genomes (KEGG) as well as 46 glycoside hydrolase (GH) and 40 glycosyl transferase (GT) genes annotated in the Carbohydrate-Active enZYmes (CAZy) database. These findings highlight XJC-1’s potential as a feline probiotic.

Phosphorylation of the influenza A virus (IAV) nucleoprotein (NP) is crucial for the viral life cycle, as it encapsidates the viral genomic RNA. Here, we employed mass spectrometry to identify serine 69 (S69) as a novel phosphorylation site of NP in IAV. Sequence homology alignment revealed that NP S69 is highly conserved across various subtypes of IAV. The S69A mutation, which is designed to mimic constant dephosphorylation, had minimal effects on viral replication and pathogenicity in both cellular and murine models. In contrast, the S69E mutation, which mimics constant phosphorylation, was lethal. Mechanistically, the phosphorylation of NP S69 reduces the polymerase activity of viral ribonucleoprotein (vRNP) by impairing the interaction between NP and PB2. Additionally, NP S69 phosphorylation inhibited NP nuclear import by disrupting its interaction with importin-α3. These findings identify NP S69 phosphorylation as a critical regulatory mechanism in IAV replication, providing valuable insights into the role of NP phosphorylation in the life cycle of influenza virus.