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.
The use of plant extracts as insecticides against vector insects serves as a perfect alternative to conventional methods. This study was carried out to assess the chemical composition and efficacy of Chromolaena odorata L. and Ocimum gratissimum L. in the control of adult houseflies. C. odorata and O. gratissimum were extracted with cold water and applied at four concentrations (5, 10, 40 and 100% v/v) in different bioassays (contact, fumigant and feeding-deterrent). A synthetic insecticide (Lambdacyhalothrin) and an untreated control were included in the treatments. The treatments were arranged in a completely randomized design with three replicates. The phytochemical compositions of the tested plant extracts were determined via gas chromatography‒mass spectrometry (GC‒MS). Mortality data were recorded at the stipulated times (1, 2, 4, 6, 8 and 24 h), and the means were separated via Duncan’s multiple range test at a 5% probability. GC‒MS revealed different chemical compounds, and eugenol, n-hexadecanoic acid, caryophyllene, phytol, humulene, 9,12,15-octadecatrienoic acid, (Z,Z,Z)-, squalene, and stigmasterol compounds, among others, were identified as active insecticidal compounds. The tested plant extracts were effective against the studied insects, which suggested synergistic action of the observed natural chemicals in the plant extracts used. Moreover, the two plant extracts did not kill the studied insects faster than the synthetic insecticide did, but 100% mortality was observed after 12 h of exposure to the plant extracts. The mode of application and concentration played a significant role in the toxicity of the plant extracts, with the feeding mode of application resulting in greater toxicity effects than the fumigant and contact bioassays at the highest concentration. However, O. gratissimum exhibited better insecticidal control than C. odorata extracts did. Therefore, the use of crude plant extracts as insecticides could serve as substitutes for lambdachyalothrin in the control of houseflies, especially in animal rearing facilities and in the human population.
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.