Search Results (78)

Background: Transmissible gastroenteritis virus (TGEV) is a highly pathogenic porcine coronavirus that causes severe gastrointestinal damage in piglets. However, how TGEV affects host iron homeostasis, oxidative stress, and the ferroptosis process remains unclear. This study aimed to investigate the effects of TGEV infection on cellular iron metabolism, oxidative damage, and lipid peroxidation-mediated ferroptosis, as well as to evaluate the potential therapeutic role of retinoic acid (RA). Methods: Using an intestinal epithelial cell model of TGEV infection, we assessed key regulators of iron handling, oxidative stress, lipid peroxidation, and ferroptosis. The expression of ferroportin (FPN) and ferritin (FTH/L) and the activity of the p62–NRF2–GPX4/HO-1 antioxidant axis were analyzed, and the effects of exogenous RA treatment on these endpoints were examined. Results: TGEV infection disrupted cellular iron homeostasis by downregulating the expression of ferroportin (FPN) and ferritin (FTH/L), leading to the accumulation of intracellular free iron, which in turn induced the generation of a large amount of reactive oxygen species (ROS) and ultimately triggered ferroptosis in intestinal epithelial cells. Additionally, TGEV infection significantly inhibited the p62-NRF2-GPX4/HO-1 antioxidant signaling pathway, further exacerbating the ferroptosis process. Conclusions: This study reveals that ferroptosis is a key pathological mechanism in TGEV-induced intestinal injury and demonstrates that RA exerts a therapeutic effect by regulating iron metabolism and activating the p62-NRF2-GPX4/HO-1 signaling pathway. These findings provide new theoretical insights for potential intervention strategies targeting virus infection-associated ferroptosis and intestinal damage. Full article

Porcine epidemic diarrhea virus (PEDV) is a major pathogen responsible for severe diarrhea, dehydration, and high mortality in neonatal piglets, continually threatening global swine production. Rapid differentiation of its major genotypes (classical G1, variant G2, and recombinant S-INDEL) is vital for molecular epidemiology and effective disease control, yet existing approaches rely mainly on time-consuming sequencing and phylogenetic analysis of the S gene. To overcome this limitation, we developed a novel triplex TaqMan-based real-time PCR assay for rapid detection and differentiation of the three PEDV genotypes. The assay demonstrated high sensitivity, with the lowest detection limit of 10² copies/μL, and strong specificity, showing no cross-reactivity with six other common swine pathogens (TGEV, PDCoV, PoRV, PRRSV, CSFV, and PRV). It also exhibited excellent reproducibility, with both intra- and inter-assay coefficients of variation maintained below 1.5%. In clinical validation, the assay showed 100% concordance with results obtained from S gene sequencing and phylogenetic analysis. Furthermore, testing of 160 clinical samples revealed cases of co-infection involving G2 and S-INDEL strains. In conclusion, this rapid, specific, and reproducible assay provides a reliable tool for routine molecular diagnosis, facilitating large-scale epidemiological surveillance and enabling genotype-informed control strategies against PEDV. Full article

Swine enteric coronaviruses (SECoVs), including transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome coronavirus (SADS-CoV), are major enteric pathogens causing severe diarrhea, dehydration, high neonatal mortality, and substantial global economic losses. Rapid viral evolution and recombination continually generate antigenically diverse variants that limit cross-protection and undermine vaccine efficacy, particularly for PEDV genogroup II strains that now dominate worldwide circulation. This review synthesizes current knowledge on epidemiology, diagnostic innovations, and emerging vaccine platforms, with emphasis on advances since 2022. Recent progress includes molecular surveillance tools, rapid point-of-care diagnostics, and next-generation vaccine technologies such as mRNA-based and virus-like particle platforms. However, significant knowledge gaps persist regarding viral evolution dynamics, co-infection synergies, and zoonotic spillover potential, particularly following documented human infections with PDCoV. Effective long-term control requires integrated genomic surveillance, strengthened farm-level biosecurity, rationally designed multivalent vaccines targeting conserved epitopes, and harmonized international surveillance systems to reduce outbreak risk and enhance pandemic preparedness at the human–animal interface. Full article

Background: Transmissible gastroenteritis virus (TGEV), a coronavirus (CoV) infecting pigs, uses its spike (S) glycoprotein to bind porcine aminopeptidase N (pAPN) for cell entry. Although structural studies have identified receptor-binding motifs (RBMs) within the receptor-binding domain (RBD) of the S protein, the functional relevance of individual residues for TGEV receptor recognition, cell entry, and infection remain unclear. Methods: In this study, we performed structure-guided mutagenesis of the TGEV RBD to evaluate the contribution of specific residues to receptor binding and viral infectivity. Results: Using soluble RBD proteins, we found that most of the RBD residues within the pAPN-binding interface contribute to the binding interaction. Nonetheless, TGEV reverse genetics experiments revealed that just three RBD residues (Gly527, Tyr528, and Trp571) were indispensable for viral cell entry. Mutations at these positions, which are conserved among group 1 alpha-CoVs abolished infectivity, highlighting their central role in the virus–receptor interface. Conclusions: Our findings provide a detailed functional map of the TGEV RBD and offer insights into the evolution of receptor recognition across CoV. Full article

The rapid evolution of coronaviruses (CoVs) requires researchers to develop specific yet broad-spectrum detection methods to monitor their constant genomic changes. The goal of the present study was to establish a current pan-coronavirus RT-PCR system capable of detecting a wide variety of CoVs and useful for the investigation of virus diversity and host spectrum. For optimization, one-step and two-step nested RT-PCRs with three RT enzymes were examined, amplifying a ~600 bp long product of the RNA-dependent RNA polymerase. As templates, the in vitro transcribed RNA of ten pathogenic CoVs (SARS-CoV, SARS-CoV-2, NL-63, OC43, feline CoV, porcine epidemic diarrhea virus or PEDV, transmissible gastroenteritis virus or TGEV, canine CoV, bat CoV, and infectious bronchitis virus) were applied instead of the often-used DNA standards. A limit of detection of 5–50 copies/reaction was achieved with a random hexamer-primed two-step RT-PCR and a touchdown cycling profile, representing a lower detection limit and higher specificity compared to previously published primer sets. Swine origin pooled samples (n = 121), collected from apparently healthy herds in Hungary, were tested with the novel RT-PCR system. Sequences of porcine respiratory CoV/TGEV and porcine hemagglutinating encephalomyelitis virus were identified in 24 oral fluid and nasal swab pools, demonstrating the circulation of these viruses in this country, as well as the suitability of the new PCR for their detection. The results highlighted the importance of adequate RT enzyme selection and the use of RNase inhibitors in sample preparation and conservation. Full article

The emergence and spread of swine coronaviruses represent a growing challenge for both veterinary medicine and public health. These viruses exhibit high mutation rates, recombination potential, and the capacity for cross-species transmission. Among the most relevant pathogens are PEDV, TGEV, PRCV, PHEV, PDCoV, and SADS-CoV, which have caused significant outbreaks in swine production systems worldwide, with severe economic consequences. Recent evidence demonstrates coronavirus circulation in wild boar populations across Europe, including Italy, Spain, and Germany. Although wild boars are not confirmed as primary reservoirs, their ecological behavior and increasing overlap with domestic pigs raise concern over their potential role in maintaining viral circulation. Future research priorities should focus on developing a more integrated and coordinated system for the control of swine coronaviruses, including strengthened surveillance in both domestic pigs and wild boar populations, the use of molecular epidemiology techniques to identify emerging variants, and structured collaboration among veterinary, ecological, health, and regulatory sectors. Finally, investment is needed in the development of next-generation vaccines and diagnostic tools to address the considerable genetic variability of swine coronaviruses and to improve the prevention and early detection of and response to future epidemic threats. Full article

Transmissible gastroenteritis (TGE), caused by the TGE virus (TGEV), is a highly contagious enteric disease characterized by vomiting, dehydration, and watery diarrhea. It mainly endangers piglets within two weeks of age, with a 100% mortality rate, inflicting severe economic losses on the global swine industry. Since enteric tropism of the virus and mucosa serves as the first line of defense against viral invasion, an oral vaccine inducing sufficient secretory immunoglobulin A (SIgA) antibodies in animals should be developed. Being a generally recognized as safe (GRAS) microorganism, Bacillus subtilis can form endospores under extreme environmental conditions, which confer resistance to the hostile gastric environment and have been widely employed as delivery vehicles for oral vaccines owing to their immunoadjuvant activity and non-specific antidiarrheal effects. In this study, the AD antigenic epitope of the TGEV S protein was selected as the immunogen. The mature peptide of the B subunit of the heat-labile enterotoxin from enterotoxigenic Escherichia coli served as a mucosal adjuvant, and B. subtilis WB800N was used as the delivery host to construct the recombinant strain pHT43-LTB-AD/WB800N. After confirming the successful expression of the target protein, oral immunization was performed using mice as a model. The results demonstrated that this recombinant strain induced robust mucosal, humoral, and cellular immunity, along with considerable levels of neutralizing antibodies. These findings indicate that recombinant B. subtilis could serve as an oral vaccine candidate to combat TGEV infections. Full article

Red blood cells (RBCs) are essential for transporting oxygen from lungs to peripheral tissues. However, the impact of transmissible gastroenteritis virus (TGEV) infection on RBCs and its potential pathophysiological significance during disease progression remain largely unexplored. In this study, hematological analysis of TGEV-infected piglets revealed significant reduction in both RBC distribution width–coefficient of variation and RBC distribution width–standard deviation, alongside elevated pCO₂ levels. Viral detection confirmed the presence of TGEV within RBCs from infected piglets. Further investigation demonstrated that TGEV could bind to, but not replicate in, RBCs. TGEV-bound RBCs exhibited crenated and impaired deformability, which were associated with reduced oxygen-carrying capacity. Additionally, TGEV infection promoted macrophage-mediated phagocytosis of RBCs and led to decreased serum iron levels, factors that might enhance TGEV infection. Collectively, these results demonstrated the involvement of RBCs in the progression of TGEV infection, providing new insights for the development of diagnostic and therapeutic strategies. Full article

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

Porcine deltacoronavirus (PDCoV) is a newly discovered porcine intestinal coronavirus that can pose a significant threat to the global commercial swine industry. We established an enzyme-linked immunosorbent assay (ELISA) detection method for the detection of PDCoV antibodies, based on the recombinant nucleocapsid (N) protein expressed using a baculovirus system. The assay was validated using positive and negative serum samples obtained from experimentally immunized rabbits and demonstrated an absence of cross-reactivity with either transmissible gastroenteritis virus (TGEV) or porcine epidemic diarrhea virus (PEDV). The recombinant PDCoV N protein antigen dilution (0.8 μg/mL), sample serum (1:400), and the enzyme-labeled secondary antibody (1:50) were used in this assay. The cut-off value was 0.355, without cross-reactivity including TGEV and PEDV. The ELISA method shows good sensitivity (96.67%), specificity (85.51%), and reproductivity (CV < 10%). We utilized the method to detect PDCoV antibodies in 600 pig serums collected from Zhejiang Province in the last four years (2021–2024). The results showed significant differences in antibody levels between regions and considerable fluctuation in positivity rates across the four-year period. As shown in the results, we developed a sensitive and specific ELISA method for detecting anti-PDCoV N antibodies, which provides a rapid and reliable diagnostic tool for PDCoV surveillance and control. This assay demonstrates significant potential for both epidemiological investigations and commercial applications in swine disease management. Full article

Transmissible gastroenteritis virus (TGEV) represents a critical intestinal pathogen responsible for acute enteritis in pigs, posing significant challenges to global swine production biosecurity. N⁶-methyladenosine (m⁶A), the most abundant epitranscriptomic mark in eukaryotic messenger RNA, has emerged as a regulatory factor in host–virus interactions. Despite its recognized importance, the functional significance of m⁶A modifications during TGEV infection of porcine jejunal epithelial (IPEC-J2) cells remains unexplored. Here, we established a TGEV-infected IPEC-J2 cell model and we employed methylated RNA immunoprecipitation sequencing (MeRIP-seq) to comprehensively profile the m⁶A epitranscriptomic landscape and identify N⁶-methyladenosine-bearing transcripts in IPEC-J2 cells following TGEV challenge. A total of 14,813 m⁶A peaks were identified in the IPEC-J2, distributed in 7728 genes, mainly enriched in the CDS and 3′-UTRs. After TGEV infection, we identified 832 m⁶A peaks and 1660 genes with significant changes. Integrative analysis revealed a direct positive relationship between N⁶-methyladenosine modification abundance and transcript expression levels. Through integrated examination of MeRIP-Seq and RNA-Seq datasets, we identified 105 transcripts bearing m⁶A modifications, which were mainly enriched in the mTOR signaling pathway. Protein–protein interaction (PPI) network and RT-qPCR analysis demonstrated that SOS2 probably acts an important moderator in TGEV infection. This work contributes to understanding the m⁶A modification landscape in the TGEV-swine model and suggests SOS2 as potential target for future antiviral strategies. Full article

Porcine enteric coronaviruses (CoVs), including swine acute diarrhea syndrome coronavirus (SADS-CoV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and porcine transmissible gastroenteritis virus (TGEV), are major pathogens causing porcine viral diarrhea syndrome (VDS), which brings significant economic losses to the swine industry; distinguishing between these clinically similar viruses has become a serious challenge. We developed a highly specific and interference-resistant porcine CoV multiplex digital PCR (dPCR) assay. The assay exhibited robust anti-interference capabilities, as the concentrations of the four viruses did not affect their accurate quantification. The coefficients of variation (CV%) of intra-batch and inter-batch repeatability for all target viruses were less than 11%. The limit of quantification (LoQ) of this dPCR assay reached 7.5 copies/reaction for each target, and it was one order of magnitude more sensitive than qPCR. The limits of detection (LoD) for SADS-CoV, PEDV, PDCoV, and TGEV were 2.72, 3.00, 3.56, and 3.19 copies/reaction, respectively. A total of 408 known samples were used for validation tests, and the results were highly consistent with the known conditions, showing a compliance rate of 97–100%. The diagnostic specificity (Dsp) of the method was 99–100%. In conclusion, the developed multiplex dPCR assay is highly suitable for early detection and quarantine in four porcine CoVs. The results indicate that this dPCR method is characterized by high specificity, anti-interference capabilities, repeatability, and high sensitivity. It also demonstrates a high compliance rate and diagnostic specificity in sample detection. This multiplex dPCR will contribute to the control of porcine enteric CoV-caused VDS and provide clues for subsequent research. Full article

The cross-species spillover of coronaviruses is considered a serious public health risk. Feline coronavirus (FCoV), canine coronavirus (CCoV), and transmissible gastroenteritis virus (TGEV) are all classified under Alphacoronavirus suis and infect companion animals and livestock. Due to their frequent contact with humans, these viruses pose a potential risk of future cross-species transmission. Molnupiravir, a prodrug of N4-hydroxycytidine, exhibits potent antiviral activity against SARS-CoV-2, a member of the Betacoronavirus genus, and has been approved for the treatment of COVID-19. Molnupiravir was recently shown to be effective against FCoV, suggesting broad-spectrum antiviral activity across coronavirus lineages. Based on these findings, the present study investigated whether molnupiravir is also effective against CCoV and TGEV, which belong to the same Alphacoronavirus suis species as FCoV. We examined the in vitro antiviral effects of molnupiravir using four viral strains: FCoV-1 and -2, CCoV-2, and TGEV. Molnupiravir inhibited plaque formation, viral antigen expression, the production of infectious viral particles, and viral RNA replication in a dose-dependent manner in all strains. IC₅₀ values for CCoV-2 and TGEV, calculated using a feline-derived cell line (fcwf-4), were significantly lower than those for FCoV, suggesting higher sensitivity to molnupiravir. These results demonstrate that molnupiravir exhibited broad antiviral activity against animal coronaviruses classified under Alphacoronavirus suis, providing a foundation for antiviral strategies to mitigate the future risk of cross-species transmission. Full article

PoRV is a significant etiological agent of neonatal diarrhea in piglets, resulting in substantial economic losses within the global swine industry due to elevated mortality rates and reduced productivity. To address the urgent need for accessible and rapid diagnostics in resource-limited settings, we have developed a CRISPR/Cas12a-based assay integrated with recombinase polymerase amplification (RPA) for the visual detection of PoRV. This platform specifically targets the conserved VP6 gene using optimized RPA primers and crRNA, harnessing Cas12a’s collateral cleavage activity to enable dual-readout via fluorescence or lateral flow dipsticks (LFDs). The assay demonstrates a detection limit of 10² copies/μL within 1 h, exhibiting no cross-reactivity with phylogenetically related pathogens such as Transmissible Gastroenteritis Virus (TGEV). By eliminating reliance on thermal cyclers or specialized equipment, this method is fully deployable in swine farms, veterinary clinics, or field environments. The lateral flow format provides immediate colorimetric results that require minimal technical expertise, while the fluorescence mode allows for semi-quantitative analysis. This study presents a robust and cost-effective platform for decentralized PoRV surveillance in swine populations, addressing the critical need for portable diagnostics in resource-limited settings and enhancing veterinary health management. Full article

Porcine transmissible gastroenteritis virus (TGEV) is a highly contagious pathogen causing severe diarrhea in pigs, particularly piglets, leading to significant economic losses. Distinguishing TGEV from the genetically similar porcine respiratory coronavirus (PRCV) remains challenging due to their high genomic homology. In this study, we developed a one–pot assay combining recombinase-aided amplification (RAA) and CRISPR/Cas13a technology, targeting the TGEV S gene. This method was optimized for sensitivity and specificity, with orthogonal tests determining the optimal reagent concentrations. The assay achieved a detection limit of 4.13 copies/µL within 40 min at 37 °C, demonstrating no cross-reactivity with other porcine viruses. Clinical validation on 140 samples showed 100% concordance with RT–qPCR and RT–PCR results. Since the established method is completed in a single reaction tube, it eliminates the need for step-by-step operations, simplifying the process and reducing the risk of cross–contamination and false positives in subsequent tests. Overall, this assay shows promising potential for TGEV detection. Full article