Veterinary microbiology最新文献

{"title":"African swine fever virus pNP419L inhibits host translation and increases viral replication through the PERK/eIF2α pathway","authors":"Xueying Wang ,&nbsp;Zixuan Wang ,&nbsp;Yilin Guo ,&nbsp;Sai Niu ,&nbsp;Rui Liang ,&nbsp;Lin Cheng ,&nbsp;Hakimeh Baghaei Daemi ,&nbsp;Guiqing Peng","doi":"10.1016/j.vetmic.2026.110920","DOIUrl":"10.1016/j.vetmic.2026.110920","url":null,"abstract":"<div><div>African swine fever (ASF) is a highly contagious disease caused by African swine fever virus (ASFV), which poses a significant threat to pig farming worldwide. Although ASFV encodes many self-sustaining proteins, its mRNA translation relies on the host’s translation machinery. However, the mechanisms by which ASFV-encoded proteins regulate the host’s translation process in infected cells remain largely unexplored. In this study, we investigated how ASFV-encoded proteins affect the translation of host cells. We identified 21 ASFV genes, excluding those from multigene families, that significantly inhibited Renilla luciferase (Rluc) activity. Among these genes, only NP419L, which is known as an early-expressed gene, demonstrated a strong inhibitory effect. We showed that NP419L significantly suppressed host protein synthesis, independent of its enzymatic activity. Our study, which utilized confocal microscopy and biochemical assays, revealed significant implications for ASFV infection. We found that ASFV pNP419L localized to the endoplasmic reticulum (ER), induced ER stress and activated the PERK/eIF2α pathway, resulting in the inhibition of host translation. Furthermore, viral assays demonstrated that knockdown of NP419L effectively reduced viral replication and significantly restored host gene expression. Overall, our findings improve the understanding of how the ASFV protein inhibits host translation and reveal a novel function of ASFV pNP419L beyond its DNA ligase activity for the first time, providing critical insights into translational regulation during ASFV infection.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110920"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146143755","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}

{"title":"Raccoon dog parvovirus NS1 protein antagonizes type I interferon signaling by promoting selective autophagic degradation of IRF3","authors":"Wen-yu Cao ,&nbsp;Rui-qi Wang ,&nbsp;Jin-yang Zheng ,&nbsp;Ping Ma ,&nbsp;Bo Hu ,&nbsp;Cheng-qi Zhang ,&nbsp;Ya-jie Sun ,&nbsp;Jia-jia Liu ,&nbsp;Ding-rui Guo ,&nbsp;Zi-han Zhao ,&nbsp;Xin Cao ,&nbsp;Xue Bai ,&nbsp;Li-wen Xu","doi":"10.1016/j.vetmic.2026.110934","DOIUrl":"10.1016/j.vetmic.2026.110934","url":null,"abstract":"<div><div>Raccoon dog parvovirus (RDPV) is a primary causative agent of infectious enteritis in raccoon dogs. Recently, RDPV has remained prevalent in both fur-bearing and wild animal populations, exhibiting increasing pathogenicity. However, the mechanisms by which RDPV evades host innate immunity remain poorly understood. In this study, we demonstrate that RDPV infection significantly inhibits 2′3'-cGAMP-induced transcription of IFN-β and interferon-stimulated genes (ISGs) in MDCK cells. Over expression of the NS1 protein in HEK293T cells further revealed that NS1 antagonizes the cGAS-STING pathway, suppressing IFN-β and interferon-stimulated response element (ISRE) reporter activities while downregulating mRNA levels of IFN-β, ISG15, and MX1. Mechanistically, Co-immunoprecipitation (Co-IP) and confocal microscopy analyses confirmed an interaction between NS1 and IRF3, which resulted in the downregulation of IRF3 at both the mRNA and protein levels. Notably, NS1 did not affect TBK1-mediated phosphorylation of IRF3 but significantly impaired its nuclear translocation. Furthermore, NS1 was found to recruit the autophagy receptors NBR1, OPTN, and p62 to facilitate the autophagic degradation of IRF3, thereby blocking type I interferon (IFN-I) signaling. In conclusion, this study elucidates a mechanism by which RDPV NS1 inhibits the host IFN-I response via the autophagic degradation of IRF3, providing new insights into viral immune evasion and highlighting the NS1–IRF3 axis as a potential target for future antiviral strategy development against RDPV infection.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110934"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146143774","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}

{"title":"Comparative genomics of Ornithobacterium spp. isolated from free range layer chickens with respiratory infections unveils marked genetic diversity and putative new species","authors":"Chathuri H. Rodrigo ,&nbsp;Sathya N. Kulappu Arachchige ,&nbsp;Sahar Zare ,&nbsp;Rhys N. Bushell ,&nbsp;Arif Anwar ,&nbsp;Jiongrui Huang ,&nbsp;Peter Scott ,&nbsp;Amir H. Noormohammadi ,&nbsp;Marc S. Marenda","doi":"10.1016/j.vetmic.2026.110897","DOIUrl":"10.1016/j.vetmic.2026.110897","url":null,"abstract":"<div><div>The bacterium <em>Ornithobacterium rhinotracheale</em> causes upper respiratory tract infections (URTI) in commercial poultry worldwide. Efficient diagnostic and control of this emerging pathogen require accurate understanding of its classification, prevalence and distribution. The present study explores the genetic diversity of sixty-seven organisms presumptively identified as <em>Ornithobacterium</em> and recovered from chickens with URTIs in Australian free-range layer farms. Rep-PCR fingerprinting revealed wide diversity of isolates between and within farms and sites of infection. Forty representative isolates were sequenced entirely and compared to published genomes. Sequence alignments of the <em>rpoB</em> gene supported their classification into the genus <em>Ornithobacterium</em>, and 16S rRNA analysis revealed 98.08 % to 100 % identity with <em>O. rhinotracheale</em> type-strain DMS15997. However, most isolates gave non-interpretable profiles with the current Multi Locus Sequence Typing (MLST) scheme. Average Nucleotide Identity (ANI) analysis separated the dataset into four genetically divergent clusters. Most of the published <em>O. rhinotracheale</em> genomes, including DMS15997, belonged to the largest group, whereas the other clusters contained isolates with ANI values ranging from 84 % to 92 % against DMS15997, suggesting the presence of new species or sub-species. Pan-genome analysis was consistent with these observations, identifying only a small set of core genes (n = 254) in the dataset, while delineating distinct subsets of accessory proteins for each ANI cluster. Core single nucleotide polymorphism phylogeny confirmed further the substantial genetic diversity of the isolates. This study underlines the complex epidemiology and taxonomy of <em>Ornithobacterium</em>-associated URTIs in poultry farms, and is expected to improve diagnostic and control programs for this pathogen.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110897"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039139","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}

{"title":"UL24 deletion attenuates Marek's disease virus replication and pathogenicity","authors":"Yunzhe Kang ,&nbsp;Xiuwen Yang ,&nbsp;Rui Wang ,&nbsp;Wenhui Zhu ,&nbsp;Lulu Yao ,&nbsp;Lijie Lv ,&nbsp;Yongkun Du ,&nbsp;Guoqing Zhuang ,&nbsp;Aijun Sun","doi":"10.1016/j.vetmic.2026.110903","DOIUrl":"10.1016/j.vetmic.2026.110903","url":null,"abstract":"<div><div>Marek’s disease virus (MDV), a highly oncogenic alphaherpesvirus of chickens, causes severe immunosuppression and fatal T-cell lymphomas. The <em>UL24</em> gene is conserved among alphaherpesviruses and contributes to viral replication and pathogenesis in several members of this subfamily; however, its role in MDV remains undefined. Here, we constructed a <em>UL24</em>-deletion mutant (Md5BACΔUL24) and its repaired revertant (Md5BACΔUL24-Re) in the virulent Md5 strain using Red-mediated recombination. <em>In vitro</em>, <em>UL24</em> deletion significantly impaired viral replication, as evidenced by smaller plaque size and reduced viral genome copies compared to parental and revertant viruses. In specific pathogen-free (SPF) chickens, <em>UL24</em> deficiency markedly decreased viral loads in the spleen, prevented lymphoid organ atrophy, and abolished tumor development, indicating a profound attenuation of virulence. Bioinformatic analyses revealed a putative nuclear localization signal and a conserved PD-(D/E)XK endonuclease motif within MDV <em>UL24</em>, suggesting involvement in nuclear processes critical for replication. Collectively, these findings establish <em>UL24</em> as a critical role of MDV replication and pathogenesis and represent a promising target for the rational design of attenuated or recombinant MDV vaccine vectors.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110903"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079314","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}

{"title":"Replacement of the Loop 4 region in CPV VP2 with corresponding PPV segments affects N-terminal cleavage, VLP morphology, hemagglutination, and cell binding","authors":"Shengke Chang ,&nbsp;Wenjun Meng ,&nbsp;Jie Li ,&nbsp;Cun Qu ,&nbsp;Na Li ,&nbsp;Rongjun Wang","doi":"10.1016/j.vetmic.2026.110919","DOIUrl":"10.1016/j.vetmic.2026.110919","url":null,"abstract":"<div><div>Canine parvovirus (CPV) and porcine parvovirus (PPV) are closely related <em>Protoparvoviruses</em> whose major capsid protein VP2 is essential for virus-like particle (VLP) assembly and hemagglutination (HA). To investigate structural determinants of VP2 function, two chimeric CPV VP2 constructs were generated by replacing the Loop 4 region with the corresponding PPV segment, either in full-length (CL) or truncated (CTL) form. SDS-PAGE and western blotting revealed complete N-terminal cleavage of VP2 into VP3 in both constructs. Electron microscopy showed that CL VLPs had increased diameters, whereas CTL VLPs formed defective particles with reduced size and irregular morphology. HA activity was abolished in both chimeric VLPs. Cell binding assays with CL VLPs demonstrated that Loop 4 substitution caused loss of attachment to F81 cells (feline kidney cell line) and PK15 cells (porcine kidney cell line), whereas wild-type CPV VP2 and PPV VP2 VLPs retained their respective cell-specific binding. These results demonstrated that Loop 4 was a critical determinant for maintaining capsid structural integrity and functional orientation, including particle size regulation, HA, and VLP-cell interactions. This study provided mechanistic insights into how conformational perturbations or structural defects in the three-fold spike affected viral function, offering a framework for dissecting VP2 structural and functional divergence across <em>Protoparvoviruses</em>.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110919"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146114374","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}

{"title":"Salmonella virulence factor sptP activates the NLRP3/Caspase-1 pathway to induce pyroptosis and exacerbate intestinal injury in chicks","authors":"Bo Zhang ,&nbsp;Ke Li ,&nbsp;Hongya Yan ,&nbsp;Rong Zhao ,&nbsp;Zhenju Yuan ,&nbsp;Changrui Xiao ,&nbsp;Chengji Yang ,&nbsp;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>^<em>-</em>) 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&amp;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>^<em>-</em>) 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":"2026-03-01","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}

{"title":"Feasibility of 16S rRNA gene qPCR for rapid detection of pathogenic bacteria in bovine cerebrospinal fluid","authors":"Sara Ferrini ,&nbsp;Patrizia Nebbia ,&nbsp;Ugo Ala ,&nbsp;Maria Cristina Stella ,&nbsp;Giulia Cagnotti ,&nbsp;Giorgia Di Muro ,&nbsp;Marzia Pezzolato ,&nbsp;Elena Bozzetta ,&nbsp;Giuliano Borriello ,&nbsp;Claudio Bellino ,&nbsp;Barbara Iulini ,&nbsp;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":"2026-03-01","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}

{"title":"Canonical Wnt signaling is not activated in vitro or in vivo by Lawsonia intracellularis infection","authors":"Caitlin Klaeui ,&nbsp;Talita Pilar Resende ,&nbsp;Connie Jane Gebhart ,&nbsp;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> &gt; 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> &gt; 0.9999) or <em>c-Myc</em> (<em>p</em> &gt; 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":"2026-03-01","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}

{"title":"Longitudinal assessment of Ehrlichia canis bacterial load in naturally infected dogs using droplet digital PCR","authors":"Peeravit Sumpavong ,&nbsp;Krittanut Kanittakul ,&nbsp;Sarawan Kaewmongkol ,&nbsp;Gunn Kaewmongkol","doi":"10.1016/j.vetmic.2026.110896","DOIUrl":"10.1016/j.vetmic.2026.110896","url":null,"abstract":"<div><div>Persistence of detectable <em>Ehrlichia canis</em> DNA after a full course of doxycycline treatment remains poorly described. Highly sensitive molecular tools are essential for monitoring this phenomenon. This study aimed to monitor <em>E. canis</em> DNAemia in naturally infected dogs over a 60-day follow-up period using droplet digital PCR (ddPCR) and to compare its performance with TaqMan real-time PCR (qPCR). Forty-one seropositive dogs (identified by the IDEXX SNAP 4Dx Plus test) exhibiting clinical signs consistent with canine monocytic ehrlichiosis (CME) were enrolled as the Day 0 group. Follow-up samples were collected during recovery from partially overlapping cohorts at Days 30 (n = 21) and 60 (n = 14). At Day 0, ddPCR detected <em>E. canis</em> in 33 of 41 dogs (82.92 %), outperforming qPCR (25/41; 60.97 %). At Days 30 and 60, ddPCR detected <em>E. canis</em> DNA in 12 of 21 (57.14 %) and 5 of 14 (35.71 %) dogs, respectively, while qPCR detected only 2 of 21 (9.52 %) at Day 30 and none at Day 60. Quantification of bacterial loads showed a significant decline from a median of 2.28 DNA copies/µL at Day 0–0.067 copies/µL at Day 30 (<em>P</em> &lt; 0.05), and 0.0614 copies/µL by Day 60 (<em>P</em> &lt; 0.05). Dogs with hematocrit (Hct) levels below 25 % on Day 0 were significantly more likely to have ddPCR-positive results at Day 30 (<em>P</em> = 0.035), suggesting a potential association between severe anemia at diagnosis and persistent DNAemia. The high sensitivity of ddPCR revealed persistence of detectable <em>E. canis</em> DNA with very low bacterial loads. These prolonged bacterial DNAemia require further studies incorporating viability assays to clarify whether residual DNAemia reflects persistent viable infection or non-viable bacterial DNA.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110896"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146012500","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}

{"title":"PRRSV nucleocapsid and nonstructural proteins dual-regulate CD40 expression via ATF-2 and AP-1 pathways","authors":"Chaolun Fu ,&nbsp;Hongyan Gao ,&nbsp;Yingchao Li,&nbsp;Chang Liu,&nbsp;Yuzhong Zhao,&nbsp;Youbo Li,&nbsp;Zhong Liu,&nbsp;Man Lu,&nbsp;Yang Shen,&nbsp;Yajing Xing,&nbsp;Yu Wang,&nbsp;Xiaotong Wu,&nbsp;Pingping Yang,&nbsp;Yihong Xiao","doi":"10.1016/j.vetmic.2026.110899","DOIUrl":"10.1016/j.vetmic.2026.110899","url":null,"abstract":"<div><div>Macrophage surface molecules critically regulate inflammatory responses. Porcine reproductive and respiratory syndrome virus (PRRSV), an immunosuppressive pathogen with marked tropism for porcine alveolar macrophages, modulates host surface receptor expression to facilitate infection. Here, we screened the expression of immunoregulatory molecules during PRRSV infection and identified CD40 as the most significantly upregulated transcript. We demonstrated that the PRRSV nucleocapsid protein (N) enhances CD40 promoter activity, whereas nonstructural proteins Nsp1α, Nsp11, and Nsp12 suppress it. Mechanistically, protein N upregulated CD40 via the transcription factor ATF-2, while Nsp1α, Nsp11, and Nsp12 downregulated CD40 through AP-1. CD40 overexpression restricted PRRSV replication, suggesting its potential as a target for antiviral strategies.</div></div>","PeriodicalId":23551,"journal":{"name":"Veterinary microbiology","volume":"314 ","pages":"Article 110899"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146030980","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}