Pub Date : 2026-01-16DOI: 10.1016/j.vetmic.2026.110895
Xue-Lian Zhang , Xiao-Wen Li , Wei-Hao Tan , Jia-Run Yang , Jie-Yue Liang , Jian-Wei Shao
Nairobi sheep disease virus (NSDV), a tick-borne orthonairovirus that causes lethal hemorrhagic gastroenteritis in small ruminants, has recently expanded eastward into China. However, its molecular pathogenesis remains poorly understood. In this study, time-course transcriptomic profiling of NSDV-infected BHK-21 cells revealed a progressive reprogramming of the autophagy pathway, characterized by significant up-regulation of autophagy-related genes. Enhanced autophagosome formation and accelerated autophagosome–lysosome fusion were confirmed by electron microscopy and mRFP-GFP-LC3 flux assays. Pharmacological blockade of autophagy with chloroquine markedly reduced viral RNA accumulation and concurrently enhanced type I interferon responses, indicating that NSDV actively exploits autophagy to facilitate replication and dampen innate immunity. These findings identify autophagy as a proviral mechanism essential for optimal NSDV replication and suggest that targeting this pathway could offer a novel therapeutic strategy against emerging nairoviral infections.
{"title":"Transcriptomic profiling reveals that NSDV exploits autophagy as a proviral mechanism to enhance viral replication","authors":"Xue-Lian Zhang , Xiao-Wen Li , Wei-Hao Tan , Jia-Run Yang , Jie-Yue Liang , Jian-Wei Shao","doi":"10.1016/j.vetmic.2026.110895","DOIUrl":"10.1016/j.vetmic.2026.110895","url":null,"abstract":"<div><div>Nairobi sheep disease virus (NSDV), a tick-borne orthonairovirus that causes lethal hemorrhagic gastroenteritis in small ruminants, has recently expanded eastward into China. However, its molecular pathogenesis remains poorly understood. In this study, time-course transcriptomic profiling of NSDV-infected BHK-21 cells revealed a progressive reprogramming of the autophagy pathway, characterized by significant up-regulation of autophagy-related genes. Enhanced autophagosome formation and accelerated autophagosome–lysosome fusion were confirmed by electron microscopy and mRFP-GFP-LC3 flux assays. Pharmacological blockade of autophagy with chloroquine markedly reduced viral RNA accumulation and concurrently enhanced type I interferon responses, indicating that NSDV actively exploits autophagy to facilitate replication and dampen innate immunity. These findings identify autophagy as a proviral mechanism essential for optimal NSDV replication and suggest that targeting this pathway could offer a novel therapeutic strategy against emerging nairoviral infections.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110895"},"PeriodicalIF":2.7,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145998980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intestinal infection by Lawsonia intracellularis in swine causes epithelial hyperplastic lesions in crypts that resemble those induced by aberrant activation of canonical Wnt signaling. The objective of this study was to evaluate evidence of canonical Wnt signaling activation induced by L. intracellularis infection in vitro and in vivo. Cell lines Caco-2, intestinal porcine enterocytes (IPEC-J2), rat intestinal epithelial cells (IEC-18), mouse McCoy cells, a Wnt reporter cell line, and swine ileal enteroids were infected with L. intracellularis. Cell culture media and McCoy cell lysate were collected after 48 h and tested for Wnt activation using a Wnt Reporter Assay. No increase in Wnt activation was detected among non-infected and infected cell lines (p > 0.05) or enteroids (p = 0.1704). Wnt signaling activation across samples was not different from reporter cells exposed to media alone. RNA from cell lysates was evaluated for differential gene expression (DGE) of Wnt target genes CyclinD1 and c-Myc by qPCR. There were no differences in gene expression between non-infected and infected McCoy (p = 0.2666, p = 0.0558), IEC-18 (p = 0.160, p = 0.2009), IPEC-J2 (p = 0.1274, p = 0.2659), or reporter (p = 0.2740, p = 0.3278) cells. Archival samples of pig intestines presenting hyperplastic lesions caused by experimental infection with L. intracellularis were evaluated for cellular localization of β-catenin and DGE. Immunostaining showed membrane but no nuclear β-catenin in lesions and surrounding normal tissue. DGE analysis of non-infected and infected tissue revealed no difference in CyclinD1 (p > 0.9999) or c-Myc (p > 0.9999) expression. In summary, we found no evidence of canonical Wnt signaling activation induced by L. intracellularis in vitro or in pig tissues.
{"title":"Canonical Wnt signaling is not activated in vitro or in vivo by Lawsonia intracellularis infection","authors":"Caitlin Klaeui , Talita Pilar Resende , Connie Jane Gebhart , Milena Saqui-Salces","doi":"10.1016/j.vetmic.2026.110877","DOIUrl":"10.1016/j.vetmic.2026.110877","url":null,"abstract":"<div><div>Intestinal infection by <em>Lawsonia intracellularis</em> in swine causes epithelial hyperplastic lesions in crypts that resemble those induced by aberrant activation of canonical Wnt signaling. The objective of this study was to evaluate evidence of canonical Wnt signaling activation induced by <em>L. intracellularis</em> infection <em>in vitro</em> and <em>in vivo</em>. Cell lines Caco-2, intestinal porcine enterocytes (IPEC-J2), rat intestinal epithelial cells (IEC-18), mouse McCoy cells, a Wnt reporter cell line, and swine ileal enteroids were infected with <em>L. intracellularis.</em> Cell culture media and McCoy cell lysate were collected after 48 h and tested for Wnt activation using a Wnt Reporter Assay. No increase in Wnt activation was detected among non-infected and infected cell lines (<em>p</em> > 0.05) or enteroids (<em>p</em> = 0.1704). Wnt signaling activation across samples was not different from reporter cells exposed to media alone. RNA from cell lysates was evaluated for differential gene expression (DGE) of Wnt target genes <em>CyclinD1</em> and <em>c-Myc</em> by qPCR. There were no differences in gene expression between non-infected and infected McCoy (<em>p</em> = 0.2666, <em>p</em> = 0.0558), IEC-18 (<em>p</em> = 0.160, <em>p</em> = 0.2009), IPEC-J2 (<em>p</em> = 0.1274, <em>p</em> = 0.2659), or reporter (<em>p</em> = 0.2740, <em>p</em> = 0.3278) cells. Archival samples of pig intestines presenting hyperplastic lesions caused by experimental infection with <em>L. intracellularis</em> were evaluated for cellular localization of β-catenin and DGE. Immunostaining showed membrane but no nuclear β-catenin in lesions and surrounding normal tissue. DGE analysis of non-infected and infected tissue revealed no difference in <em>CyclinD1</em> (<em>p</em> > 0.9999) or <em>c-Myc</em> (<em>p</em> > 0.9999) expression. In summary, we found no evidence of canonical Wnt signaling activation induced by <em>L. intracellularis in vitro</em> or in pig tissues.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110877"},"PeriodicalIF":2.7,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146012414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.vetmic.2026.110884
R M Schmid, E Studer, A Kapopoulou, B Yilmaz, J Becker
Antimicrobial use (AMU) in Swiss bovines is widespread, and treatment incidences are high especially in calves, fattening bull and dairy cows. In contrast, AMU in heifers is very low. It is largely unknown to what extend bacteria resistant to antimicrobials are present in this population and which phenotypes, if any, are common. In the present study, on 30 farms implementing the most frequent husbandry systems, we followed heifers during a three-months period from spring to autumn 2023 and sampled 486 heifers (each one twice) by rectal swab sampling, isolating one random isolate per heifer and yielding a total of 966 Escherichia (E.) coli isolates. These were used to infer prevalence of antimicrobial resistance through phenotypic testing using disk diffusion and, if persistence with the herd was suspected, subjected to genetic testing using whole genome sequencing. The phenotypic prevalence was low at sampling timepoints (7.3-14.2 % of isolates exhibiting resistance to >1 drug). The most frequent phenotype was streptomycin-tetracycline (n = 37), and sul2 and tetB were the most frequent resistance genes. Surprisingly, on two farms without AMU, E. coli with identical phenotype, respectively, were isolated in spring an autumn, partly in the very same individual. Single nucleotide polymorphism (SNP) differences of 2 and < 10 of isolates obtained from farms, respectively, indicate harbouring of clonal resistant bacteria. Potential explanations for this finding, among others, may be that persistence of certain isolates in the cattle gut is longer than previously thought after cessation of selection pressure, or that isolates are maintained in the population through circulation via other animals or inanimate items. Therefore, also animals of livestock production categories with little AMU shall be considered when establishing One Health approaches to combat antimicrobial resistance.
{"title":"Long-term persistence of clonal resistant and multidrug resistant E. coli despite absence of antimicrobial use in weaned dairy heifer rearing systems in Switzerland.","authors":"R M Schmid, E Studer, A Kapopoulou, B Yilmaz, J Becker","doi":"10.1016/j.vetmic.2026.110884","DOIUrl":"https://doi.org/10.1016/j.vetmic.2026.110884","url":null,"abstract":"<p><p>Antimicrobial use (AMU) in Swiss bovines is widespread, and treatment incidences are high especially in calves, fattening bull and dairy cows. In contrast, AMU in heifers is very low. It is largely unknown to what extend bacteria resistant to antimicrobials are present in this population and which phenotypes, if any, are common. In the present study, on 30 farms implementing the most frequent husbandry systems, we followed heifers during a three-months period from spring to autumn 2023 and sampled 486 heifers (each one twice) by rectal swab sampling, isolating one random isolate per heifer and yielding a total of 966 Escherichia (E.) coli isolates. These were used to infer prevalence of antimicrobial resistance through phenotypic testing using disk diffusion and, if persistence with the herd was suspected, subjected to genetic testing using whole genome sequencing. The phenotypic prevalence was low at sampling timepoints (7.3-14.2 % of isolates exhibiting resistance to >1 drug). The most frequent phenotype was streptomycin-tetracycline (n = 37), and sul2 and tetB were the most frequent resistance genes. Surprisingly, on two farms without AMU, E. coli with identical phenotype, respectively, were isolated in spring an autumn, partly in the very same individual. Single nucleotide polymorphism (SNP) differences of 2 and < 10 of isolates obtained from farms, respectively, indicate harbouring of clonal resistant bacteria. Potential explanations for this finding, among others, may be that persistence of certain isolates in the cattle gut is longer than previously thought after cessation of selection pressure, or that isolates are maintained in the population through circulation via other animals or inanimate items. Therefore, also animals of livestock production categories with little AMU shall be considered when establishing One Health approaches to combat antimicrobial resistance.</p>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"315 ","pages":"110884"},"PeriodicalIF":2.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146126622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.vetmic.2025.110862
Zhenxiang Rong , Mingjin Jiao , Nan Cao , Mingxing Lu , Shudan Liu , Chao Zhang , Liuqing Wei , Yamei Li , Huanchun Chen , Xiangmin Li , Ping Qian
Seneca Valley virus (SVV), a member of the Picornaviridae family，which is closely associated with porcine idiopathic vesicular disease (PIVD), spread quickly and has posed a potential threat to the swine industry in several countries. Currently, SVA demonstrate persistent genetic evolution, yet no licensed vaccines or effective therapeutics are commercially available for disease containment，which underscores the significance of strategies for preventing and controlling SVA infection. A Venezuelan equine encephalitis virus (VEEV) replicon system expressing Vesicular stomatitis virus glycoprotein (VSVG) was constructed in the preliminary research. In this study, we developed a recombinant virus-like vesicles (rVLVs) vaccine expressed SVA VP1 and VP2 protein based on the VEEV-VSVG system and evaluated the characterization and stability. Subsequently, immunization with rVLVs vaccine elicited robust humoral and cellular immune responses in both mice and swine. In addition, the swine challenge experiment manifested that immunization with rVLVs-SVA-VP2 conferred complete protection, comparable to the inactivated vaccine, whereas rVLVs-SVA-VP1 vaccination demonstrated a 60 % protective efficacy.
{"title":"SVA virus-like vesicle vaccine based on VEEV-VSVG vector elicits efficient immune responses and protection in swine","authors":"Zhenxiang Rong , Mingjin Jiao , Nan Cao , Mingxing Lu , Shudan Liu , Chao Zhang , Liuqing Wei , Yamei Li , Huanchun Chen , Xiangmin Li , Ping Qian","doi":"10.1016/j.vetmic.2025.110862","DOIUrl":"10.1016/j.vetmic.2025.110862","url":null,"abstract":"<div><div><em>Seneca Valley virus</em> (SVV), a member of the <em>Picornaviridae</em> family，which is closely associated with porcine idiopathic vesicular disease (PIVD), spread quickly and has posed a potential threat to the swine industry in several countries. Currently, SVA demonstrate persistent genetic evolution, yet no licensed vaccines or effective therapeutics are commercially available for disease containment，which underscores the significance of strategies for preventing and controlling SVA infection. A <em>Venezuelan equine encephalitis virus</em> (VEEV) replicon system expressing <em>Vesicular stomatitis virus</em> glycoprotein (VSVG) was constructed in the preliminary research. In this study, we developed a recombinant virus-like vesicles (rVLVs) vaccine expressed SVA VP1 and VP2 protein based on the VEEV-VSVG system and evaluated the characterization and stability. Subsequently, immunization with rVLVs vaccine elicited robust humoral and cellular immune responses in both mice and swine. In addition, the swine challenge experiment manifested that immunization with rVLVs-SVA-VP2 conferred complete protection, comparable to the inactivated vaccine, whereas rVLVs-SVA-VP1 vaccination demonstrated a 60 % protective efficacy.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110862"},"PeriodicalIF":2.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.vetmic.2026.110881
Sara Ferrini , Patrizia Nebbia , Ugo Ala , Maria Cristina Stella , Giulia Cagnotti , Giorgia Di Muro , Marzia Pezzolato , Elena Bozzetta , Giuliano Borriello , Claudio Bellino , Barbara Iulini , Antonio D’Angelo
Bacterial meningoencephalitis (BME) in cattle is responsible for economic losses due to mortality, neurological impairment, and decreased productivity. The use of cerebrospinal fluid (CSF) bacterial culture—the gold standard for antemortem bacterial detection—is limited by its lengthy processing times and potential false negatives. With this study we wanted to determine whether 16S rRNA gene real-time quantitative PCR (16S rRNA qPCR) of DNA extracted from CSF could be used to detect BME in cattle. We applied a modified low-biomass microbial investigation protocol to extract CSF DNA from 15 healthy cattle and 14 cattle diagnosed with BME. Environmental, DNA extraction, and PCR controls were performed. Bacteria were detected by culture and/or direct smear microscopy in 4 of the 14 BME cases, in 3 of which 16S rRNA qPCR yielded positive results. Overall, there was no statistically significant difference between the bacterial load measured via 16S rRNA qPCR in the BME cases and that of the healthy controls and the DNA extraction controls. While 16S rRNA qPCR demonstrated its ability to detect bacterial DNA in the CSF samples with high microbial load, it was unable to reliably distinguish BME cases from healthy controls when bacterial load was low. The question remains whether this limitation is due to the absence of bacteria in the CSF—despite underlying infection—or whether a low bacterial load is masked by background contamination. More comprehensive sequencing approaches may provide an answer.
{"title":"Feasibility of 16S rRNA gene qPCR for rapid detection of pathogenic bacteria in bovine cerebrospinal fluid","authors":"Sara Ferrini , Patrizia Nebbia , Ugo Ala , Maria Cristina Stella , Giulia Cagnotti , Giorgia Di Muro , Marzia Pezzolato , Elena Bozzetta , Giuliano Borriello , Claudio Bellino , Barbara Iulini , Antonio D’Angelo","doi":"10.1016/j.vetmic.2026.110881","DOIUrl":"10.1016/j.vetmic.2026.110881","url":null,"abstract":"<div><div>Bacterial meningoencephalitis (BME) in cattle is responsible for economic losses due to mortality, neurological impairment, and decreased productivity. The use of cerebrospinal fluid (CSF) bacterial culture—the gold standard for antemortem bacterial detection—is limited by its lengthy processing times and potential false negatives. With this study we wanted to determine whether 16S rRNA gene real-time quantitative PCR (16S rRNA qPCR) of DNA extracted from CSF could be used to detect BME in cattle. We applied a modified low-biomass microbial investigation protocol to extract CSF DNA from 15 healthy cattle and 14 cattle diagnosed with BME. Environmental, DNA extraction, and PCR controls were performed. Bacteria were detected by culture and/or direct smear microscopy in 4 of the 14 BME cases, in 3 of which 16S rRNA qPCR yielded positive results. Overall, there was no statistically significant difference between the bacterial load measured via 16S rRNA qPCR in the BME cases and that of the healthy controls and the DNA extraction controls. While 16S rRNA qPCR demonstrated its ability to detect bacterial DNA in the CSF samples with high microbial load, it was unable to reliably distinguish BME cases from healthy controls when bacterial load was low. The question remains whether this limitation is due to the absence of bacteria in the CSF—despite underlying infection—or whether a low bacterial load is masked by background contamination. More comprehensive sequencing approaches may provide an answer.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110881"},"PeriodicalIF":2.7,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.vetmic.2026.110882
Bo Zhang , Ke Li , Hongya Yan , Rong Zhao , Zhenju Yuan , Changrui Xiao , Chengji Yang , Aiguo Xin
Salmonella enterica serovar Enteritidis (SE) is a major foodborne pathogen causing severe intestinal diseases in humans and animals, posing significant global public health and economic burdens. The Salmonella protein tyrosine phosphatase (sptP), a type III secretion system effector and critical SE virulence factor, contributes to pathogenesis, but its precise role in SE-induced intestinal injury remains unclear. Specifically, whether sptP modulates the NLRP3/Caspase-1 inflammasome (a central inflammatory regulator) is undefined. To address this, we constructed an sptP gene deficient SE strain (sptP-) via CRISPR/Cas9, verified by PCR and sequencing. Given that MCC950 is a selective NLRP3 inflammasome inhibitor, we designed an animal study to examine the contribution of sptP to SE pathogenicity in chicks and its potential interplay with NLRP3 activation. Chicks were randomly divided into 5 groups (n = 10/group): SE sptP⁺ (wild-type), sptP⁻ (mutant), sptP⁺+MCC950 (NLRP3 inhibitor), sptP⁻+MCC950, and PBS control. Ileal tissues were collected 24 h post-infection. Histopathological injury was scored via H&E staining. Bacterial burdens in the ileum and spleen were quantified by plate counting. Cytokine levels (IL-1β, IL-18) were measured using ELISA and RT‑PCR. Protein expression (pro‑caspase‑1, cleaved‑caspase‑1, GSDMD, GSDMD‑N) was analyzed by Western blot, and pyroptosis was quantified via LDH release assay. The sptP mutant (sptP-) was successfully generated without unintended mutations. The sptP⁻ infection reduced IL-1β/IL-18 expression, cleaved-caspase-1 and GSDMD-N levels, and significantly diminished pyroptosis. MCC950 pretreatment markedly attenuated pathology in sptP⁺-infected chicks, including reduced Caspase-1/GSDMD cleavage, lower inflammatory cytokines, decreased pyroptosis, and alleviated intestinal damage. Notably, no significant differences in pathology, cytokines, or pyroptosis markers were observed between sptP⁻ and sptP⁻+MCC950 groups. Importantly, bacterial loads did not differ across groups, excluding colonization differences as a confounding factor. These findings demonstrate that sptP promotes SE-induced intestinal injury by activating the host NLRP3/Caspase-1 inflammasome pathway, driving inflammatory cytokine release and pyroptosis. This study clarifies a previously undefined mechanism by which sptP exacerbates SE-associated intestinal damage, addressing the knowledge gap regarding its regulation of the NLRP3 inflammasome.
{"title":"Salmonella virulence factor sptP activates the NLRP3/Caspase-1 pathway to induce pyroptosis and exacerbate intestinal injury in chicks","authors":"Bo Zhang , Ke Li , Hongya Yan , Rong Zhao , Zhenju Yuan , Changrui Xiao , Chengji Yang , Aiguo Xin","doi":"10.1016/j.vetmic.2026.110882","DOIUrl":"10.1016/j.vetmic.2026.110882","url":null,"abstract":"<div><div><em>Salmonella</em> enterica serovar Enteritidis (<em>SE</em>) is a major foodborne pathogen causing severe intestinal diseases in humans and animals, posing significant global public health and economic burdens. The <em>Salmonella</em> protein tyrosine phosphatase (sptP), a type III secretion system effector and critical <em>SE</em> virulence factor, contributes to pathogenesis, but its precise role in <em>SE</em>-induced intestinal injury remains unclear. Specifically, whether <em>sptP</em> modulates the NLRP3/Caspase-1 inflammasome (a central inflammatory regulator) is undefined. To address this, we constructed an <em>sptP</em> gene deficient <em>SE</em> strain (<em>sptP</em><sup><em>-</em></sup>) via CRISPR/Cas9, verified by PCR and sequencing. Given that MCC950 is a selective NLRP3 inflammasome inhibitor, we designed an animal study to examine the contribution of <em>sptP</em> to <em>SE</em> pathogenicity in chicks and its potential interplay with NLRP3 activation. Chicks were randomly divided into 5 groups (n = 10/group): <em>SE sptP⁺</em> (wild-type), <em>sptP⁻</em> (mutant), <em>sptP⁺</em>+MCC950 (NLRP3 inhibitor), <em>sptP⁻</em>+MCC950, and PBS control. Ileal tissues were collected 24 h post-infection. Histopathological injury was scored via H&E staining. Bacterial burdens in the ileum and spleen were quantified by plate counting. Cytokine levels (IL-1β, IL-18) were measured using ELISA and RT‑PCR. Protein expression (pro‑caspase‑1, cleaved‑caspase‑1, GSDMD, GSDMD‑N) was analyzed by Western blot, and pyroptosis was quantified via LDH release assay. The <em>sptP</em> mutant (<em>sptP</em><sup><em>-</em></sup>) was successfully generated without unintended mutations. The <em>sptP⁻</em> infection reduced IL-1β/IL-18 expression, cleaved-caspase-1 and GSDMD-N levels, and significantly diminished pyroptosis. MCC950 pretreatment markedly attenuated pathology in <em>sptP⁺</em>-infected chicks, including reduced Caspase-1/GSDMD cleavage, lower inflammatory cytokines, decreased pyroptosis, and alleviated intestinal damage. Notably, no significant differences in pathology, cytokines, or pyroptosis markers were observed between <em>sptP⁻</em> and <em>sptP⁻</em>+MCC950 groups. Importantly, bacterial loads did not differ across groups, excluding colonization differences as a confounding factor. These findings demonstrate that <em>sptP</em> promotes <em>SE</em>-induced intestinal injury by activating the host NLRP3/Caspase-1 inflammasome pathway, driving inflammatory cytokine release and pyroptosis. This study clarifies a previously undefined mechanism by which <em>sptP</em> exacerbates <em>SE</em>-associated intestinal damage, addressing the knowledge gap regarding its regulation of the NLRP3 inflammasome.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110882"},"PeriodicalIF":2.7,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.vetmic.2026.110879
Xiaoyu Zhang , Ying Li , Xin Liu , Ming Zhou , Ling Zhao
Canine coronavirus (CCoV) is a significant enteric pathogen in dogs, particularly in group-housed conditions. Although it is classically associated with mild enteritis, its high mutation rate drives genetic diversification, influencing virulence and reducing the effectiveness of traditional vaccines. To address this challenge, a novel CCoV strain, WH2023, was isolated from a breeding facility in Wuhan, Central China. Phylogenetic analysis of the spike (S) gene suggested that WH2023 is the predominant CCoV-IIa subtype. Pathogenicity studies in puppies revealed high virulence, with 100 % morbidity after a high challenge dose (106 TCID50/mL), severe diarrhea and lethargy, intestinal lesions in the jejunum and ileum, and high viral loads consistent with typical CCoV pathogenesis. An inactivated vaccine based on WH2023 and formulated with the GEL02 adjuvant was developed and evaluated in beagle puppies. Safety assessments revealed an excellent profile, and immunogenicity studies revealed strong neutralizing antibody responses, reaching titers of 1:5404 (12.4 log2) one week after booster vaccination. Vaccinated dogs were fully protected against the WH2023 challenge, whereas unvaccinated controls developed gastroenteritis. Neutralizing antibody titers in vaccinated dogs remained above 1:32 for up to 300 days and significantly exceeded those induced by commercial vaccines available in China. These findings indicate that WH2023 is a highly virulent CCoV-IIa strain and a promising candidate for vaccine development, providing enhanced safety and long-lasting protection against canine coronavirus infection.
{"title":"Identification and vaccine efficacy evaluation of a canine coronavirus isolated in central China","authors":"Xiaoyu Zhang , Ying Li , Xin Liu , Ming Zhou , Ling Zhao","doi":"10.1016/j.vetmic.2026.110879","DOIUrl":"10.1016/j.vetmic.2026.110879","url":null,"abstract":"<div><div>Canine coronavirus (CCoV) is a significant enteric pathogen in dogs, particularly in group-housed conditions. Although it is classically associated with mild enteritis, its high mutation rate drives genetic diversification, influencing virulence and reducing the effectiveness of traditional vaccines. To address this challenge, a novel CCoV strain, WH2023, was isolated from a breeding facility in Wuhan, Central China. Phylogenetic analysis of the spike (S) gene suggested that WH2023 is the predominant CCoV-IIa subtype. Pathogenicity studies in puppies revealed high virulence, with 100 % morbidity after a high challenge dose (10<sup>6</sup> TCID<sub>50</sub>/mL), severe diarrhea and lethargy, intestinal lesions in the jejunum and ileum, and high viral loads consistent with typical CCoV pathogenesis. An inactivated vaccine based on WH2023 and formulated with the GEL02 adjuvant was developed and evaluated in beagle puppies. Safety assessments revealed an excellent profile, and immunogenicity studies revealed strong neutralizing antibody responses, reaching titers of 1:5404 (12.4 log2) one week after booster vaccination. Vaccinated dogs were fully protected against the WH2023 challenge, whereas unvaccinated controls developed gastroenteritis. Neutralizing antibody titers in vaccinated dogs remained above 1:32 for up to 300 days and significantly exceeded those induced by commercial vaccines available in China. These findings indicate that WH2023 is a highly virulent CCoV-IIa strain and a promising candidate for vaccine development, providing enhanced safety and long-lasting protection against canine coronavirus infection.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110879"},"PeriodicalIF":2.7,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145967051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.vetmic.2026.110878
Michelle Wiebe, Angelo Antiguas, Sashi Kant, Michael Beck, Raksha Tiwari, Philip R. Hardwidge, Luchang Zhu
Streptococcus suis is a major zoonotic bacterial pathogen that poses significant challenges to both the swine industry and human health. Suilysin, a secreted cytotoxin produced by S. suis, is a critical virulence factor that facilitates bacterial invasion, dissemination, and disruption of the blood-brain barrier. However, the regulation of suilysin production remains incompletely understood. This study demonstrates that the Ihk/Irr two-component system regulates suilysin expression in highly virulent ST1 serotype 2 S. suis strains. Deletion of the ihk and irr genes resulted in significant reductions in suilysin transcript levels and protein abundance. Furthermore, loss of the Ihk/Irr system decreased bacterial cytotoxicity to a level comparable to that observed in a suilysin deletion mutant. Genome-wide transcriptomic analysis revealed that, in addition to suilysin, this two-component system regulates a broad array of genes, including those encoding transcriptional regulators, ABC transporters, and putative virulence factors such as the surface antigen Sao and the cell wall endopeptidase PepO. Overall, this work identifies new regulatory targets of the Ihk/Irr system in S. suis, providing deeper insight into how this pathogen coordinates the expression of its virulence factors.
{"title":"A two-component system regulating suilysin production in ST1 serotype 2 Streptococcus suis","authors":"Michelle Wiebe, Angelo Antiguas, Sashi Kant, Michael Beck, Raksha Tiwari, Philip R. Hardwidge, Luchang Zhu","doi":"10.1016/j.vetmic.2026.110878","DOIUrl":"10.1016/j.vetmic.2026.110878","url":null,"abstract":"<div><div><em>Streptococcus suis</em> is a major zoonotic bacterial pathogen that poses significant challenges to both the swine industry and human health. Suilysin, a secreted cytotoxin produced by <em>S. suis</em>, is a critical virulence factor that facilitates bacterial invasion, dissemination, and disruption of the blood-brain barrier. However, the regulation of suilysin production remains incompletely understood. This study demonstrates that the Ihk/Irr two-component system regulates suilysin expression in highly virulent ST1 serotype 2 <em>S. suis</em> strains. Deletion of the <em>ihk</em> and <em>irr</em> genes resulted in significant reductions in suilysin transcript levels and protein abundance. Furthermore, loss of the Ihk/Irr system decreased bacterial cytotoxicity to a level comparable to that observed in a suilysin deletion mutant. Genome-wide transcriptomic analysis revealed that, in addition to suilysin, this two-component system regulates a broad array of genes, including those encoding transcriptional regulators, ABC transporters, and putative virulence factors such as the surface antigen Sao and the cell wall endopeptidase PepO. Overall, this work identifies new regulatory targets of the Ihk/Irr system in <em>S. suis</em>, providing deeper insight into how this pathogen coordinates the expression of its virulence factors.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110878"},"PeriodicalIF":2.7,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-06DOI: 10.1016/j.vetmic.2026.110876
Abdul Karim Khalid , Doukun Lu , Gang Zhao , Yong Li , Chao Wang , Ye Zhi , Tahira Iftakhar , Aizhen Guo , Yingyu Chen
Mycoplasma bovis causes significant economic losses in cattle production, yet its pathogenic mechanisms remain incompletely understood. In this study, we characterize MbovP537 as a novel virulence factor and diagnostic marker for M. bovis. Bioinformatic analysis confirmed its identity as a secreted aromatic cluster surface protein (296 aa) with high antigenicity (VaxiJen score: 1.45). Recombinant MbovP537 (rMbovP537) exhibited strong immunogenicity in indirect ELISA, demonstrating 93.3 % sensitivity and 96.7 % specificity (AUC = 0.95) in detecting natural infections in cattle. Functional analysis revealed that deletion of MbovP537 abolished bacterial adhesion (5.6-fold reduction vs. wild-type, P < 0.001) without affecting growth, while attenuating proinflammatory responses (P < 0.001) in BoMac cells. Complementation partially restored both adhesion and inflammation. Crucially, endotoxin-free rMbovP537 directly triggered dose-dependent upregulation of IL-1β, IL-6, and IL-8 (P < 0.001 at 10 μg/mL), In contrast, the anti-inflammatory cytokines IL-4 and IL-10 were not significantly affected. These results indicated that MbovP537 may be essential for host colonization and immunopathology, while its diagnostic performance supports its potential applications in serological testing.
{"title":"Investigating the pro-inflammatory role of a secreted protein MbovP537 from Mycoplasma bovis: Potential as a diagnostic marker","authors":"Abdul Karim Khalid , Doukun Lu , Gang Zhao , Yong Li , Chao Wang , Ye Zhi , Tahira Iftakhar , Aizhen Guo , Yingyu Chen","doi":"10.1016/j.vetmic.2026.110876","DOIUrl":"10.1016/j.vetmic.2026.110876","url":null,"abstract":"<div><div><em>Mycoplasma bovis</em> causes significant economic losses in cattle production, yet its pathogenic mechanisms remain incompletely understood. In this study, we characterize MbovP537 as a novel virulence factor and diagnostic marker for <em>M. bovis</em>. Bioinformatic analysis confirmed its identity as a secreted aromatic cluster surface protein (296 aa) with high antigenicity (VaxiJen score: 1.45). Recombinant MbovP537 (rMbovP537) exhibited strong immunogenicity in indirect ELISA, demonstrating 93.3 % sensitivity and 96.7 % specificity (AUC = 0.95) in detecting natural infections in cattle. Functional analysis revealed that deletion of MbovP537 abolished bacterial adhesion (5.6-fold reduction vs. wild-type, P < 0.001) without affecting growth, while attenuating proinflammatory responses (P < 0.001) in BoMac cells. Complementation partially restored both adhesion and inflammation. Crucially, endotoxin-free rMbovP537 directly triggered dose-dependent upregulation of IL-1β, IL-6, and IL-8 (P < 0.001 at 10 μg/mL), In contrast, the anti-inflammatory cytokines IL-4 and IL-10 were not significantly affected. These results indicated that MbovP537 may be essential for host colonization and immunopathology, while its diagnostic performance supports its potential applications in serological testing.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110876"},"PeriodicalIF":2.7,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-06DOI: 10.1016/j.vetmic.2026.110874
Shichao Yuan , Rui Fu , Bangfeng Xu , Wenqing Wang , Huamao Ding , Xue Pan , Chunxiu Yuan , Qinfang Liu , Zhifei Zhang , Qiaoyang Teng , Xiaona Shi , Minghao Yan , Peirong Jiao , Dawei Yan , Zejun Li
Since 2015, outbreaks of goose Astrovirus type 2 (GAstV-2) have caused significant economic losses in the goose industry by inducing severe visceral and articular gout in goslings, with mortality rates reaching up to 50 %. The capsid (Cap) protein of GAstV-2 is the primary structural protein that elicits immune responses, but it has not been extensively studied for neutralizing epitopes or infection mechanisms. In this study, two novel neutralizing monoclonal antibodies (mAbs) 4A7 and 8H3 were generated, which specifically target the Cap protein and effectively inhibit GAstV-2 infection in vitro. Epitope mapping using alanine-scanning mutagenesis revealed that the epitopes recognized by mAbs 4A7 and 8H3 are located within the amino acids sequences 443ESCSFLVF450 and 425QVTPSLVYNF434 of the Cap protein, respectively. These two epitopes are highly conserved among GAstV-2 strains, but show substantial divergence from GAstV-1 strains. Structural analysis indicated that these epitopes are situated on the surface of the Cap protein, within the P2 domain, which is critical for virus-receptor interactions and immune recognition. The findings not only identify novel neutralizing epitopes in GAstV-2 but also highlight the potential of mAbs 4A7 and 8H3 for developing epitope-based vaccines and diagnostic assays.
{"title":"Identification of novel B-cell neutralizing epitopes in goose Astrovirus type 2","authors":"Shichao Yuan , Rui Fu , Bangfeng Xu , Wenqing Wang , Huamao Ding , Xue Pan , Chunxiu Yuan , Qinfang Liu , Zhifei Zhang , Qiaoyang Teng , Xiaona Shi , Minghao Yan , Peirong Jiao , Dawei Yan , Zejun Li","doi":"10.1016/j.vetmic.2026.110874","DOIUrl":"10.1016/j.vetmic.2026.110874","url":null,"abstract":"<div><div>Since 2015, outbreaks of goose Astrovirus type 2 (GAstV-2) have caused significant economic losses in the goose industry by inducing severe visceral and articular gout in goslings, with mortality rates reaching up to 50 %. The capsid (Cap) protein of GAstV-2 is the primary structural protein that elicits immune responses, but it has not been extensively studied for neutralizing epitopes or infection mechanisms. In this study, two novel neutralizing monoclonal antibodies (mAbs) 4A7 and 8H3 were generated, which specifically target the Cap protein and effectively inhibit GAstV-2 infection in <em>vitro</em>. Epitope mapping using alanine-scanning mutagenesis revealed that the epitopes recognized by mAbs 4A7 and 8H3 are located within the amino acids sequences <sup>443</sup>ESCSFLVF<sup>450</sup> and <sup>425</sup>QVTPSLVYNF<sup>434</sup> of the Cap protein, respectively. These two epitopes are highly conserved among GAstV-2 strains, but show substantial divergence from GAstV-1 strains. Structural analysis indicated that these epitopes are situated on the surface of the Cap protein, within the P2 domain, which is critical for virus-receptor interactions and immune recognition. The findings not only identify novel neutralizing epitopes in GAstV-2 but also highlight the potential of mAbs 4A7 and 8H3 for developing epitope-based vaccines and diagnostic assays.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"313 ","pages":"Article 110874"},"PeriodicalIF":2.7,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145935043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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