Enterovirus G (EV-G) is an important enteric pathogen widely circulating in swine populations and is characterized by considerable genetic diversity and recombination potential. In recent years, recombinant EV-G strains carrying exogenous papain-like cysteine protease (PLCP) gene insertions have been increasingly reported; however, their genotype distribution and molecular characteristics in major pig-producing regions remain poorly understood. In this study, 356 clinical samples collected from Guangxi, southern China, between 2020 and 2025 were screened for EV-G, and 13 representative strains were subjected to whole-genome sequencing and sequence analysis. The overall EV-G positivity rate in Guangxi was 20.51% (73/356). Phylogenetic analysis showed that the 13 Guangxi EV-G strains were mainly classified into three genotypes, G1, G2, and G8, with G1 being the predominant genotype. Notably, PLCP gene insertions of 573-642 nt were identified at the 2C/3A junction in seven strains belonging to three distinct genotypes, G1, G2, and G8, demonstrating the cross-genotype distribution of PLCP insertions within a single geographic region. Phylogenetic analysis of the PLCP sequences demonstrated that all Guangxi-derived PLCP sequences clustered within the EV-G-PLCP clade and were clearly separated from the torovirus PLCP clade. Recombination analysis retained three potential recombination events with clearer combined support from RDP4 and SimPlot analyses, involving Guangxi strains GX3008, GX3022, and GX4292. Selection pressure analysis showed that the VP1 gene was overall under negative selection. Collectively, these findings demonstrate the co-circulation of multiple EV-G genotypes, the cross-genotype distribution of PLCP insertions, and the presence of potential recombination events in Guangxi. This study provides new evidence for understanding the genetic diversity, genomic plasticity, and regional molecular characteristics of EV-G, and also provides an important basis for future PLCP-related functional studies and continued EV-G surveillance.

The H3N2 subtype of canine influenza virus (CIV) has emerged as a significant pathogen in canine populations since 2006, causing widespread epidemics globally. The hemagglutinin (HA) protein, particularly the HA1 subunit, plays a critical role in viral entry and is a primary target for vaccine development and antiviral therapies. In this study, we analyzed HA structure and rare codons, immunized BALB/c mice with the truncated HA protein, and generated three HA1-specific mAbs: 2A8, 3C4, and 5A3. mAbs 2A8 and 5A3 targeted the conserved epitope 211QTIIP215, while 3C4 recognized the moderately variable epitope 91SNAFS95. Analysis of H3 CIV HA sequences from GISAID revealed that 211QTIIP215 is highly conserved across H3N2 CIV strains, suggesting its potential as a target for broad-spectrum antibodies development, whereas mutations in 91SNAFS95 exhibits moderate sequence variability. These findings support the design of vaccines and diagnostics for H3N2 CIV, advancing our understanding of CIV biology.

Porcine rotavirus (PoRV) has emerged as a primary pathogen causing viral diarrhea in pigs, resulting in significant economic losses. This study was conducted to systematically characterize the epidemiology and genotypic characteristics of PoRV in Guangxi, China. A total of 870 diarrheic pig samples were collected from Guangxi during 2020-2025. The qRT-PCR results indicated an overall PoRV-positive rate of 41.38% (360/870), and the annual positivity rate showed an overall upward trend. The genetic evolutionary analysis of the VP4, VP6, and VP7 genes indicated that PoRV predominantly belonged to the A group and the predominant P genotype observed was P[13] (76.83%), while the G genotypes were G5 (36.56%) and G9 (33.33%). The most prevalent genotype combinations were G9P[13]I5 and G5P[13]I5. CH-GXGL-PoRV-3151-2021, a PoRV strain isolated from positive samples, was identified via RT-PCR, qRT-PCR, whole-genome sequencing, and IFA. This strain was assigned the 11-segment genotype constellation G9-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1 based on whole-genome sequencing. NSP1 and NSP2 showed high similarity to human rotavirus strains, whereas VP1-VP4, VP6, VP7, and NSP3-NSP5 showed high similarity to porcine rotavirus strains. This study indicates the widespread circulation of PoRV in Guangxi, with multiple G genotypes, including G9, G5, G4, G3, G2, and G26, being detected. The isolated G9P[23]I5 strain exhibits the same genotype as the strains that have become increasingly prevalent in recent years. This strain may represent a possible reassortant between porcine and human rotaviruses. This study offers significant insights into the epidemiology of PoRV and the prevalent genotypes in Guangxi, thereby supporting the development of targeted prevention strategies and novel vaccines.

BACKGROUND:Porcine astrovirus (PAstV) poses a major risk to the pig industry by causing diarrhea in suckling piglets. Despite its global prevalence and five genotypes, the virus's pathogenic mechanism is not well understood due to difficulties in isolating and culturing it in vitro. Studying PAstV from clinical samples and its interaction with host cells is crucial for understanding its pathogenesis and developing antiviral treatments. METHODS:To isolate porcine astrovirus (PAstV) from clinical specimens, fecal samples from PAstV-positive pigs were collected in August 2018, inoculated into PK-15 cells, and subjected to three successive blind passages. The in vitro growth characteristics of the isolated strain were subsequently evaluated, and the morphology of the virus particles was examined through electron microscopy. The complete genome sequence of the isolated strain was determined, followed by sequence alignment, homology analysis, phylogenetic analysis, and recombination analysis. To investigate the induction of reactive oxygen species (ROS) production in PK-15 cells infected with the isolated strain, the cells were infected, and ROS production was quantified using the MitoSOX probe. Furthermore, the expression levels of the antioxidant factors Nrf2 and HO-1 were analyzed via Western blotting. Mitochondrial damage resulting from PAstV infection was observed using transmission electron microscopy, and the effect of PAstV infection on mitochondrial membrane potential was assessed using the JC-1 probe. Finally, the impact of ROS on PAstV replication was explored using IFA and RT-qPCR. RESULTS:In this study, a strain of PAstV was isolated from porcine fecal samples, demonstrating an ability to adapt effectively to PK-15 cells with a viral titer reaching up to 10^7.85 TCID50/mL. Genetic evolution analysis classified the isolated strain as PAstV5, revealing high genetic homology with other representative PAstV5 strains. The isolated strain was designated as PAstV5-GX2. Sequence alignment identified 11 consecutive amino acid deletions at the 3' end of ORF1a in the PAstV5-GX2 strain, resulting in alterations to the three-dimensional structure of the nsp1a/4 protein. Further investigation indicated that PAstV infection in PK-15 cells enhances mitochondrial ROS production and diminishes the protein expression levels of the antioxidant molecules Nrf2 and HO-1. Concurrently, PAstV infection induces mitochondrial swelling, cristae rupture, and vacuolization, along with a reduction in mitochondrial membrane potential. Through the application of H2O2 and NAC to modulate cellular ROS levels, it was determined that ROS can facilitate viral replication. CONCLUSIONS AND RELEVANCE:Our study successfully isolated a novel strain of PAstV5 characterized by an 11-amino acid deletion in the nsp1a protein, leading to significant alterations in the three-dimensional structure of the nsp1a/4 protein. This strain was observed to induce the production of mitochondrial ROS, downregulate the expression of Nrf2 and HO-1, and cause mitochondrial damage. Furthermore, the generation of mitochondrial ROS was found to facilitate the replication of PAstV. These findings offer valuable insights into the genetic evolution and pathogenic mechanisms of PAstV.

Introduction:Mycoplasma hyopneumoniae (Mhp) infection significantly challenges Guangxi's pig farms, yet its prevalence and molecular characteristics remain poorly understood. This study aimed to define circulating Mhp genotypes and their distribution in the region. Methods:From 2022-2023, 1,362 pig lung samples were randomly collected from 14 Guangxi regions. Mhp was detected using TaqMan Real-time PCR. Strong positive samples underwent multilocus sequence typing (MLST) of adk, rpoB, and tpiA genes to assess genetic relationships. Results:Of 1,362 samples, 655 (48.1%) were Mhp-positive. MLST amplification succeeded for 61 samples, revealing 27 sequence types (24 novel) across all 14 regions. Phylogenetic analysis indicated predominant circulation of Mhp types I and V. High Mhp incidence and substantial genetic diversity were observed. Discussion:This study provides comprehensive analysis of Mhp in Guangxi, revealing high prevalence and genetic diversity dominated by types I and V. These findings expand understanding of Mhp epidemiology in China and offer a theoretical foundation for developing prevention and control strategies in Guangxi.

Porcine Teschovirus (PTV) is a highly prevalent pathogen within swine populations, primarily associated with encephalitis, diarrhea, pneumonia, and reproductive disorders in pigs, thereby posing a significant threat to the sustainable development of the pig farming industry. In this study, a novel strain of PTV was isolated from the feces of a pig exhibiting symptoms of diarrhea, utilizing PK-15 cell lines. The structural integrity of the viral particles was confirmed via transmission electron microscopy, and the viral growth kinetics and characteristics were evaluated in PK-15 cells. High-throughput sequencing facilitated the acquisition of the complete viral genome, and subsequent phylogenetic analysis and full-genome alignment identified the strain as belonging to the PTV 2 genotype. Further investigation revealed that infection with the PTV-GXLZ2024 strain induces phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α) in PK-15 cells, indicating activation of the unfolded protein response (UPR) through the PERK pathway, with minimal involvement of the IRE1 or ATF6 pathways. Notably, ATF4 protein expression was progressively downregulated throughout the infection, while downstream CHOP protein levels remained unchanged, indicating an incomplete UPR induced by PTV-GXLZ2024. Furthermore, PERK knockdown was found to enhance the replication of PTV-GXLZ2024. This study provides critical insights into the molecular mechanisms underlying PTV pathogenesis and establishes a foundation for future research into its evolutionary dynamics and interactions with host organisms.

Influenza A viruses (IAVs) pose a persistent potential threat to human health because of the spillover from avian and swine infections. Extensive surveillance was performed in 12 cities of Guangxi, China, during 2018 and 2023. A total of 2540 samples (including 2353 nasal swabs and 187 lung tissues) were collected from 18 pig farms with outbreaks of respiratory disease. From these, 192 IAV-positive samples and 19 genomic sequences were obtained. We found that the H1 and H3 swine influenza A viruses (swIAVs) of multiple lineages and genotypes have continued to co-circulate during that time in this region. Genomic analysis revealed the Eurasian avian-like H1N1 swIAVs (G4) still remained predominant in pig populations. Strikingly, the novel multiple H3N2 genotypes were found to have been generated through the repeated introduction of the early H3N2 North American triple reassortant viruses (TR H3N2 lineage) that emerged in USA and Canada in 1998 and 2005, respectively. Notably, when the matrix gene segment derived from the H9N2 avian influenza virus was introduced into endemic swIAVs, this produced a novel quadruple reassortant H1N2 swIAV that could pose a potential risk for zoonotic infection.

为建立一种可精准、快捷鉴别检测副溶血弧菌(VP)及嗜水气单胞菌(AH)的方法,根据GenBank公布的VP Tlh基因及AH aerA基因保守区序列,设计合成两对特异性引物,通过优化反应体系及反应程序,成功建立了一种可同时检测VP与AH的双重PCR方法,并开展了特异性及敏感性试验.结果显示:VP Tlh和AH aerA基因扩增条带大小分别为 500、760 bp;反应体系中Tlh与aerA基因引物最优浓度分别为 7.5、10.0 nmol/L,反应程序中最佳退火温度为 56.8℃;该方法对 VP、AH 的最低可检出细菌浓度均为1.2×103 CFU/mL;对地衣芽孢杆菌、微小杆菌、巨大芽孢杆菌、蜡阳芽孢杆菌、普通变形杆菌、维氏气单胞菌、布氏柠檬酸杆菌、豚鼠气单胞菌、霍乱弧菌、拟态弧菌、简氏气单胞菌等其他非目标菌均无交叉反应,仅对VP和AH呈特异性阳性扩增.综上,本研究建立了一种可快速鉴别诊断VP、AH的双重PCR检测方法,其特异性强、灵敏度高,可为VP、AH等细菌性病原引发的水生动物疫病的快速诊断、监测及有效防控提供技术支持.

为了建立一种能快速鉴别猪日本脑炎病毒(JEV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪细小病毒(PPV)和猪伪狂犬病病毒(PRV)的准确、高效的多重常规PCR检测方法,针对JEV、PRRSV、PPV、PRV基因保守区域合成特异性引物,优化后获得最优反应条件,对该方法特异性、敏感性、重复性进行了测定,并应用该方法对临床样品进行初步应用.结果显示,该方法对JEV、PRRSV、PPV、PRV可进行特异性扩增,对混合阳性质粒检测下限达2×106 copies/μL,对猪圆环病毒2型、猪瘟病毒、猪流行性腹泻病毒、猪丁型冠状病毒、猪传染性胃肠炎病毒等相关病毒均无扩增,且重复性良好.用该方法检测51份2021年采集的广西区内组织样品,检出JEV、PRRSV、PPV、PRV阳性率分别为7.84％、50.98％、5.88％、23.53％,且存在多重混合感染的情况.所建立的多重PCR方法具有良好的特异性、敏感性及重复性,可应用于临床常见猪繁殖障碍性病毒病的快速诊断和监测预警,为猪繁殖障碍性病毒病提供了诊断技术支持.

旨在研究猪丁型冠状病毒(porcine deltacoronavirus,PDCoV)N蛋白的抗原性,为下一步诊断试剂盒的研发提供依据.试验通过RT-PCR的方法扩增PDCoV CH/GX/1468B/2017株完整的N基因并构建原核表达质粒pET32a-N,将pET32a-N转化至大肠杆菌BL21感受态细胞中,经诱导表达获得重组N蛋白,纯化后经Western blot方法检测其反应原性,免疫昆明小鼠制备重组N蛋白多克隆抗体并进行效价测定(间接ELISA法)和特异性验证(间接免疫荧光法).结果显示:重组N蛋白在IPTG终浓度为1.0mmol/L,37℃诱导表达6 h的条件下可获得最高表达量,该重组蛋白主要以可溶性蛋白的形式表达;Western blot结果显示,纯化后的重组N蛋白可以和PDCoV阳性猪血清发生特异性结合,具有良好的反应原性.制备的多克隆抗体的效价可达1:64 000,间接免疫荧光法结果表明其能特异性识别和结合PDCoV,说明重组N蛋白具有较好免疫原性.提示:PDCoV N蛋白抗原性好,可作为诊断试剂盒的候选抗原.

针对猪德尔塔冠状病毒(PDCoV)的N基因建立检测PDCoV的SYBR Green Ⅰ荧光定量PCR方法,并验证了其特异性、敏感性和重复性等.结果显示,本方法特异性高,与猪流行性腹泻病毒、猪传染性胃肠炎病毒、猪轮状病毒、猪肠病毒、伪狂犬病病毒、猪嵴病毒、猪繁殖与呼吸综合征病毒、猪星状病毒等病原无交叉反应.本方法Ct值与标准模板浓度在108.5～103.5PFU/mL范围内呈良好的线性关系,相关系数(R2)为0.994 9,直线方程为y=-3.594 9x+41.006,最低检测限为102.50 PFU/mL.运用该方法检测PDCoV感染不同来源细胞系的病毒载量,发现的PDCoV感染宿主谱广,能感染不同来源的细胞,且在LLC-PK细胞上的复制能力最强.本研究建立的方法为PDCoV的防控提供了技术支持.

为建立猪流行性腹泻病毒(PEDV)血清学ELISA抗体检测方法,本研究以原核表达纯化的PEDV S2重组蛋白为包被抗原,通过反应条件优化,建立了一种PEDV重组S2蛋白的间接ELISA抗体检测方法.结果显示,重组蛋白抗原最佳包被量0.8 μg/孔;血清最佳稀释倍数为1 ∶40,最佳血清孵育时间为120 min;酶标二抗最佳工作浓度为1 ∶4000,最佳二抗反应时间为45 min;最佳底物显色时间为15 min;待检血清样品S/P值＞0.212时判定为阳性,待检血清样品S/P值＜0.188时判定为阴性,当0.188≤待检血清样品S/P值≤0.212时判定为可疑.以S2蛋白作为包被抗原建立的PEDV抗体间接ELISA方法仅对PEDV血清检测为阳性,与猪瘟病毒、猪丁型冠状病毒等主要猪源病毒阳性血清均无交叉反应,具有良好的特异性.该方法检测灵敏度较高、重复性好,批内和批间重复性变异系数均小于10％.利用本研究建立的PEDV S2蛋白间接ELISA抗体检测方法对广西地区不同阶段猪群血清样品共计622份进行检测,总体样品阳性率为76.05％,不同阶段阳性率相差较大.本实验建立的ELISA方法可应用于临床样品PEDV抗体检测以及PEDV血清流行病学调查.

Abstract To exploring the effects of probiotics on growth performance, immune function, blood biochemical indicators and cecal flora of broilers, 5 native experimental probiotics (Bacillus coagulans, Lactobacillus fermentum, Bacillus subtilis, Bacillus licheniformis and Enterococcus faecalis) were isolated and purified. Broilers Fufeng and Sanhuang were divided: 5 single experimental probiotic groups, 1 mixed experimental probiotic group (Lactobacillus fermentum, Bacillus subtilis, Bacillus licheniformis, Enterococcus faecalis), commercial probiotics group and negative control group. Each group had 10 replicates of each type of broilers. The experimental probiotics were added to broiler’s diet during experimental period. The growth performance was measured on 21d, 42d and 77d while the immune function, blood biochemical indexes and cecal flora were measured on 77d. The growth performance results showed that experimental probiotics could effectively increase the FCR and BWG (P <0.05); Thymus indexes (P <0.05), spleen indexes and bursa indexes were increased; The levels of IgA, IgG and IL-2 were significantly increased (P <0.05); The contents of total protein (P <0.05) and albumin increased while the total cholesterol, triglycerides (P <0.05), urea nitrogen and blood glucose (P <0.05) were decreased; The population of LAB increased (P <0.05) while E.coli decreased (P <0.05) in caecal. These results indicated that different experimental probiotics had different degree of effects on experimental broilers, but their effects were similar. And the combination of several types of experimental probiotics had a more stable beneficial effects which indicated that the isolated experimental probiotics can be used as broiler feed additives to improve broiler s immunity and health in Guangxi.

2020年10月份—2021年2月份,广西某养鸽场鸽群陆续出现乳鸽及种鸽死亡、鸽胚孵化率降低、部分种鸽有神经症状等情况,为了查找病因、确定诊治方案、降低经济损失,通过病史及用药史询问了解鸽群基本情况,采用临床检查、RT-PCR、血凝抑制试验、显微镜镜检及细菌分离鉴定等方法对病鸽进行综合诊断,并采用药敏试验选择有效药物,根据综合诊断及试验结果,对鸽场患病鸽群进行针对性防治并提出鸽场合理化防控建议.结果表明:该鸽场患病鸽确诊感染鸽Ⅰ型副黏病毒(pi-geon Paramyxo virus Ⅰ,PPMV-Ⅰ),并发感染大肠杆菌、沙门氏菌和毛滴虫,分离菌株的混合菌液对亚胺培南、头孢替坦、多黏菌素B、米诺环素、美罗培南、链霉素、阿米卡星高敏.通过对鸽群进行新城疫疫苗紧急免疫,对发病鸽群进行敏感药物系统治疗并辅以鸽舍消毒和杀菌,鸽群恢复正常,鸽场疫情得到有效控制.说明该鸽场鸽群感染了 PPMV-Ⅰ、大肠杆菌、沙门氏菌和毛滴虫,提示鸽场需提高生物安全意识,做好各类病原的防控措施及免疫程序.

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is an emerging swine enteric coronavirus that causes vomiting, severe diarrhea, dehydration and death in suckling piglets. NS7a is putative accessory protein that is predicted to be encoded by SADS-CoV, but still to be confirmed experimentally. In the present study, recombinant NS7a protein was expressed in a prokaryotic expression system and used as an antigen to prepare monoclonal antibodies (mAbs) specific to NS7a protein. We obtained two anti-NS7a mAbs, termed AH5 and EH3, that were shown by western blotting to react with the natural NS7a protein in Vero E6 cells infected with SADS-CoV. Using the produced mAbs, we observed by confocal microscopy that NS7a protein was expressed in the cytoplasm. Further studies revealed that the motif 31VNTWQEFA38 was the minimal unit of the linear B-cell epitope recognized by mAb AH5, and the motif 82FDLFERF88 was the minimal unit of the linear B-cell epitope recognized by mAb EH3. Alignment of amino acids showed that these two epitopes were highly conserved among different SADS-CoV strains and SADS-related coronaviruses from bats, but with one substitution in these two motifs in bat coronavirus HKU2. In summary, we generated and characterized two mAbs against SADS-CoV NS7a protein, and demonstrated NS7a expression in SADS-CoV-infected cells for the first time.

为建立快速、准确的猪丁型冠状病毒(PDCoV)抗体ELISA检测方法,本研究以重组蛋白N作为包被抗原,建立了 PDCoV间接ELISA抗体检测方法.结果显示,经条件筛选,确定了该ELISA最佳反应条件:重组蛋白每孔包被0.2 μg;待检血清1:80稀释,孵育60 min;酶标二抗1:4 000稀释,反应30 min;底物显色10min.待检血清样品S/P值＞0.200时判定为阳性,S/P值＜0.173时判定为阴性,S/P值介于0.173和0.200之间则判为可疑.特异性试验结果表明,该检测方法不与HCV、FMDV、PRRSV、PRV、TGEV和PEDV的阳性血清发生交叉反应;重复性试验结果显示,批内变异系数为0.79％～4.75％,批间变异系数在1.92％～6.60％之间,表明重复性良好;敏感性试验结果显示,该方法可检测到血清最大稀释度为1:320.符合率试验结果显示,本方法与中和试验检测结果符合度高,阳性符合率、阴性符合率和总符合率分别为86.36％、96.43％和92.00％.利用本研究建立的ELISA方法对456份采自广西地区不同阶段猪群的血清样品进行检测,结果显示,总体样品阳性率为40.40％,不同阶段猪群抗体阳性率有较大区别,后备母猪的阳性率可高达100％,保育猪阳性率最低仅为3.90％.

为了解广西猪场伪狂犬病毒(PRV)感染和免疫状况,2017年1月—2020年12月,对部分猪场随机采样送检的血清样品,应用ELISA方法开展PRV血清抗体检测,并对检测结果进行不同年份、不同季节、不同地区、不同生长阶段猪群的统计分析.结果显示:从时间分布上看,2018年PRV gE抗体场阳性率(57.71％)和个体阳性率(24.75％)均最高,此后呈逐年下降趋势,其中个体阳性率下降明显(P<0.05),2020年下降至6.14％;各年间的PRV gB抗体场合格率差异不显著(P>0.05),均在90％以上,而2019年的个体阳性率(88.71％)最低,与其他年份差异显著(P<0.05).冬季PRV gE和gB抗体个体阳性率最低,分别为14.96％和89.35％,与其他季节差异明显(P<0.05);冬季gE抗体场阳性率(42.97％)最低,与春季、秋季差异不显著(P>0.05),但显著低于夏季(P<0.05),而gB抗体场合格率一年四季差异不显著(P>0.05),均在95％以上.从空间分布上看,广西14个地市猪场均存在不同程度的PRV野毒感染,其中玉林市最严重,场阳性率和个体阳性率分别为69.51％和35.86％,而钦州市最轻,分别为16.67％和4.07％;PRV gB抗体个体合格率普遍较高,均在84％以上.从不同生长阶段猪群上看,后备母猪、育肥猪PRV gE和gB抗体个体阳性率均显著低于其他生长阶段猪群(P<0.05),其中gE抗体个体阳性率在13％以下,而gB抗体个体阳性率不足80％.结果表明,近年广西规模猪场PRV野毒感染率较高,而疫苗免疫并不能完全阻止野毒株感染.建议通过PRV净化和提高规模猪场生物安全水平等措施来控制其流行.本研究为制定合理的猪伪狂犬病防控与净化策略提供了依据.

Coinfection caused by various genotypes of porcine epidemic diarrhea virus (PEDV) is a new disease situation. We previously reported the coexistence of PEDV strains containing different ORF3 genotypes in China. In this study, the PEDV strains 17GXCZ-1ORF3d and 17GXCZ-1ORF3c were isolated and plaque-purified from the same piglet, which had a natural large deletion at the 172–554 bp position of the ORF3 gene or possessed a complete ORF3 gene, respectively. Meanwhile, 17GXCZ-1ORF3d had >99% nt identity with 17GXCZ-1ORF3c in the 5′UTR, ORF1a/1b, S, E, M, N and 3′UTR regions but only demonstrated low nucleotide identities (80.5%) in the ORF3 gene. To elucidate the pathogenicity, 7-day-old piglets were infected. Piglets infected with these two PEDV strains exhibited severe clinical signs and shed the virus at the highest level within 96 hpi. Compared with the piglets inoculated with the 17GXCZ-1ORF3c strain, the piglets inoculated with the 17GXCZ-1ORF3d strain had higher mortality rates (75% vs. 50%), an earlier onset of clinical signs with a significantly higher diarrhea score, lower VH:CD ratios and a higher percentage of PEDV-positive enterocytes. This study is the first to report PEDV coinfections with different ORF3 genotypes, and a PEDV strain with a large deletion in the ORF3 gene might have the advantage of a potential genetic marker, which would be useful during vaccine development.

旨在对广西玉林市某规模化猪场免疫猪流行性腹泻病毒(porcine epidemic diarrhea virus,PEDV) AJ1102疫苗株和猪传染性胃肠炎病毒(TGEV)二联弱毒活疫苗后,猪群发生的腹泻进行确诊.通过对发病猪群临床观察、腹泻死亡仔猪病理解剖、实验室RT-PCR检测和基因测序,最终诊断为PEDV变异株感染.对PEDV变异毒株的S基因进行了扩增测序与分析发现,该毒株与国内外参考毒株S基因核苷酸同源性为92.8％～ 99.5％,氨基酸同源性为91.8％ ～ 99.2％;遗传进化分析表明,该PEDV毒株属于G2-a型变异毒株;氨基酸序列比较结果显示,该PEDV变异株氨基酸在多个位点发生了变异,S蛋白在第807位与第827位疏水性氨基酸处出现了较大的变化,在抗原位点第800～813位氨基酸处发生了较为明显的变化.本研究通过该例猪流行性腹泻病毒变异株感染的临床诊断和S基因变异分析,为PEDV病原学研究以及科学防控该病提供参考依据.

近年来,猪德尔塔冠状病毒(porcine deltacoronavirus,PDCoV)给养猪业造成了较大经济损失.为快速检测PDCoV,针对病毒N基因设计特异引物,建立了PDCoV重组酶介导核酸等温扩增荧光法(RT-RAA).通过优化引物浓度、反应温度,确定了最佳反应条件,然后进行了特异性和灵敏性试验,并与普通RT-PCR方法进行了比较.结果显示:该方法特异性较好,与猪繁殖与呼吸综合征病毒、猪轮状病毒、猪伪狂犬病病毒、猪细小病毒、猪圆环病毒、猪瘟病毒、猪捷申病毒、传染性胃肠炎病毒、猪流行性腹泻病毒等猪源病毒无明显交叉反应;反应过程均在39℃恒温条件下完成,用时30 min即可得到扩增结果;反应体系可检测的最低扩增拷贝数为10 copies/μL,敏感性较高;该方法检测68份猪源病毒样品的PDCoV阳性检出率为17.6％,高于普通RT-PCR(13.2％).结果表明,本研究建立的RT-RAA快速检测PDCoV方法具有快速、特异、灵敏的优点,可用于PDCoV的快速检测和流行病学监测.