为了解山东省青岛市猫疱疹病毒Ⅰ型(FHV-1)的流行情况,2019年6月至2021年6月共采集猫眼鼻拭子样本218份,提取样本DNA后利用PCR方法进行FHV-1核酸检测,共检出阳性样本22份,阳性率为10.1％(22/218).宠物救助站猫的FHV-1阳性率(16.7％)略高于其他来源猫,2～6月龄幼猫的FHV-1阳性率(13.6％)略高于成年猫(7.0％),成年公猫阳性率(7.3％)稍高于成年母猫(6.7％),但各组间均无显著性差异(P>0.05).对2021年3月采集的60份猫血清进行了FHV-1中和抗体检测,共检出阳性样本40份,抗体阳性率为66.7％.结果表明,青岛市猫群中存在一定的FHV-1流行,抗体保护水平不高,应加快国产FHV-1相关疫苗的研制,及时对猫进行免疫预防.

2020年在某鸡场做跟踪服务时,发现该场两批蛋鸡初开产就产软壳蛋、破壳蛋,并且无产蛋高峰.分析以往的生产记录和检测数据,认为雏鸡在小日龄感染QX型传染性支气管炎(IBV),青年鸡阶段又发生了滑液囊支原体(MS),是导致该问题发生的主要原因.现将该案例的发生发展情况,综合分析及针对性防控建议汇总如下,希望对养殖生产有所借鉴和帮助.

不同的鸡滑液囊支原体(MS)分离株对鸡体的侵袭部位和侵袭力不同,根据侵袭部位可分为呼吸型、滑膜囊炎型和生殖型.近几-生殖型滑液囊支原体的发病率较高,给养殖业带来了较大的影响和经济损失,希望引起大家关注.

The H9N2 avian influenza virus is not only an important zoonotic pathogen, it can also easily recombine with other subtypes to generate novel reassortments, such as the H7N9 virus. Although H9N2 live attenuated vaccines can provide good multiple immunities, including humoral, cellular, and mucosal immunity, the risk of reassortment between the vaccine strain and wild-type virus is still a concern. Here, we successfully rescued an H9N2 live attenuated strain [rTX-NS1-128 (mut)] that can interdict reassortment, which was developed by exchanging the mutual packaging signals of HA and truncated NS1 genes and confirmed by RT-PCR and sequencing. The dynamic growth results showed that rTX-NS1-128 (mut) replication ability in chick embryos was not significantly affected by our construction strategy compared to the parent virus rTX strain. Moreover, rTX-NS1-128 (mut) had good genetic stability after 15 generations and possessed low pathogenicity and no contact transmission characteristics in chickens. Furthermore, chickens were intranasally immunized by rTX-NS1-128 (mut) with a single dose, and the results showed that the hemagglutination inhibition (HI) titers peaked at 3 weeks after vaccination and lasted at least until 11 weeks. The cellular immunity (IL-6 and IL-12) and mucosal immunity (IgA and IgG) in the nasal and trachea samples were significantly increased compared to inactivated rTX. Recombinant virus provided a good cross-protection against homologous TX strain (100%) and heterologous F98 strain (80%) challenge. Collectively, these data indicated that rTX-NS1-128(mut) lost the ability for independent reassortment of HA and NS1-128 and will be expected to be used as a potential live attenuated vaccine against H9N2 subtype avian influenza.

为建立一种检测非洲猪瘟病毒(ASFV)抗体的间接ELISA(iELISA)方法,对构建的ASFV P30基因表达工程菌诱导表达后,将获取的重组ASFV P30蛋白进行纯化和Western-blot检测,然后以纯化的重组蛋白为抗原,建立了ASFV抗体iELISA检测方法,并进行了特异性、灵敏性、重复性试验;同时与基于ASFV P30-2His6蛋白(N、C末端各融合1个His6标签)的iELISA方法进行兽医临床样本比较试验.结果显示:重组ASFV P30蛋白和重组ASFV P30-2His6蛋白在Western-blot检测中,均能与猪ASFV阳性血清产生特异性杂交带;基于重组ASFV P30蛋白iELISA的最佳反应条件为,抗原蛋白包被质量浓度20μg/mL、血清样品稀释度1:1000、酶标二抗稀释度1:40000、血清样品检测OD450阳性结果临界值0.22.该方法仅对ASFV阳性血清呈特异性反应,1:3200稀释的阳性血清仍可检出,批内试验和批间试验变异系数均小于10％,可以消除His标签所造成的假阳性反应.本研究建立的ASFV P30 iELISA检测方法为ASFV抗体检测提供了一种有效手段.

为了解我国鸡滑液囊支原体(Mycoplasmasynoviae,MS)感染的最新流行情况,本研究于2016-2019年从江苏、安徽、山东、河南、河北、宁夏、黑龙江、湖北等8个省份疑似发生MS感染的鸡场采集样品,进行MS菌株的分离鉴定,结果共获得48株MS分离株.对这些分离株的vlhA基因片段测序和分析显示,其中46株均属于K基因型,另外2株分别属于A基因型和E基因型.研究结果表明,当前国内流行的MS优势基因型是K基因型,与其他国家和地区流行的基因型存在显著性差异.本研究结果为制定适合我国鸡群MS控制与净化的策略提供了必要的流行病学依据.

为了监测我国规模化猪场伪狂犬病病毒(Pseudorabies virus,PRV)野毒感染情况,本研究采用伪狂犬gE抗体ELISA检测试剂盒对2012年2月～2017年7月送检的我国11个省份925个规模化猪场的44 809份猪血清样品进行PRV野毒抗体检测.结果 显示,925个猪场中有508个野毒阳性猪场,占检测猪场总数的54.91％,检出9153份阳性猪血清,平均阳性率为20.42％.其中种猪的野毒感染情况最明显,检出率较高,阳性率为23.19％;育肥猪的阳性检出率最低为17.22％.调查表明,我国规模化猪场猪群中仍存在PRV野毒感染.同时,本调查分析了不同地区、不同日龄猪的PRV野毒感染情况及该病的流行趋势,为我国伪狂犬病的净化提供思路.

OBJECTIVE To establish a method for evaluation of the efficacy of a classical swine fever virus (CSFV) subunit vaccine in rabbits as determined via humoral immune responses to the virus. ANIMALS 40 specific pathogen-free rabbits. PROCEDURES Rabbits were randomly assigned to 4 groups (10 rabbits/group) for SC injection of 0.05, 0.1, and 0.2 mL of a CSFV subunit E2 vaccine (representing 1.15, 2.3, or 4.6 mu g of E2 protein/dose, respectively) or saline (0.9% NaCl) solution. Blood samples were collected 21 days after vaccination for measurement of the antibody response against CSFV via ELISA and virus neutralization methods. On the same day, the CSFV Chinese (C) strain was injected into an ear vein. Vaccine efficacy was determined by monitoring of rabbits for pyrexia for 4 days and measurement of viral copies in spleen lysates at the end of the study. Reproducibility of the antibody response was tested with 2 other batches of the vaccine at the minimum immunization dose identified for the initially tested batch. RESULTS The E2 protein dose of the initially tested vaccine was positively correlated with the antibody response and protection rate in rabbits. The identified minimum immunization dose per rabbit was 0.1 mL, representing an E2 protein content of approximately 2.3 mu g, and reproducibility of the antibody response to vaccination with the 2 other batches at this dose was good. CONCLUSIONS AND CLINICAL RELEVANCE A method was established in rabbits for evaluation of the efficacy of a CSFV subunit vaccine that could help in the optimization of later large-scale vaccine production and quality control processes as well as in the clinical application of the vaccine.

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a single-stranded RNA coronavirus that causes nervous dysfunction in the infected hosts and leads to widespread alterations in the host transcriptome by modulating specific microRNA (miRNA) levels. MiRNAs contribute to RNA virus pathogenesis by promoting antiviral immune response, enhancing viral replication, or altering miRNA-mediated host gene regulation. Thus, exploration of the virus-miRNA interactions occurring in PHEV-infected host may lead to the identification of novel mechanisms combating the virus life cycle or pathogenesis. Here, we discovered that the expression of miR-10a-5p was constitutively up-regulated by PHEV in both the N2a cells in vitro and mice brain in vivo. Treatment with miR-10a-5p mimics allowed miR-10a-5p enrichment and resulted in a significant restriction in PHEV replication, suggesting widespread negative regulation of the RNA virus infection by miR-10a-5p. The outcomes were also evidenced by miR-10a-5p inhibitor over-expression. Luciferase reporter, quantitative real-time PCR (qRT-PCR), and western blotting analysis further showed that Syndecan 1 (SDC1), a cell surface proteoglycan associated with host defense mechanisms, acts as a target gene of miR-10a-5p during PHEV infection. Naturally, siRNA-mediated knockdown of SDC1 leads to a reduction in viral replication, implying that SDC1 expression is likely a favorable condition for viral replication. Together, the findings demonstrated that the abundant miR-10a-5p leads to downstream suppression of SDC1, and it functions as an antiviral mechanism in the PHEV-induced disease, providing a potential strategy for the prevention and treatment of PHEV infection in the future work.

旨在鉴定河南某蛋鸡场以心包积液、肝肿大出血为特征的病原,并对病原的免疫原性蛋白进行表达和效果分析.本研究采用病毒分离、血清学试验、PCR检测及测序分析、动物回归试验、大肠杆菌表达、蛋白纯化、攻毒保护等方法进行研究.结果 显示,所采集样品经卵黄囊途径接种7日龄SPF鸡胚,盲传2代后获得病毒;PCR可扩增出约900 bp的Hexon基因片段,经测序,其Hexon基因与血清C4型毒株的相似性为100％;血清中和试验结果表明分离的禽腺病毒为1群血清4型禽腺病毒,命名为HN-ZK株.该毒株可在鸡胚原代肝细胞上产生CPE,病毒含量可达107.5TCID50·0.1 mL-1.动物回归试验表明,该分离毒株可使35日龄SPF鸡100％ (10/10)表现出发病症状.以分离株的DNA为模板,利用大肠杆菌原核表达系统,获得相对分子质量约为33 ku的Fiber-2蛋白,离心浓缩、纯化后蛋白含量为300 mg·mL-1.将表达的Fiber-2蛋白用不同的剂量免疫SPF鸡,结果表明20μg·只-1的剂量能使鸡完全抵抗强毒株的攻击,说明Fiber-2蛋白具有较好的免疫原性.本研究可为禽心包积水-肝炎综合征的诊断和基因工程亚单位疫苗的研制提供数据参考.

Previous studies have demonstrated that transcription factor Etv5 plays an important role in the segregation between epiblast and primitive endoderm at the second fate decision of early embryo. However, it remains elusive whether Etv5 functions in the segregation between inner cell mass and trophectoderm at the first cell fate decision. In this study, we firstly generated Etv5 knockout mouse embryonic stem cells (mESCs) by CRISPR/Cas9, then converted them into extended potential stem cells (EPSCs) by culturing the cells in small molecule cocktail medium LCDM (LIF, CHIR99021, (S)-(+)-dimethindene maleate, minocycline hydrochloride), and finally investigated their differentiation efficiency of trophoblast stem cells (TSCs). The results showed that Etv5 knockout significantly decreased the efficiency of TSCs (CDX2+) differentiated from EPSCs. In addition, Etv5 knockout resulted in higher incidence of the differentiated cells with tetraploid and octoploid than that from wild type. Mechanistically, Etv5 was activated by extracellular-signal-regulated kinase (ERK) signaling pathway; in turn, Etv5 had a positive feedback on the expression of fibroblast growth factor receptor 2 (FGFR2) which lies upstream of ERK. Etv5 knockout decreased the expression of FGFR2, whose binding with fibroblast growth factor 4 was essentially needed for TSCs differentiation. Collectively, the findings in this study suggest that Etv5 is required to safeguard the TSCs differentiation by regulating FGFR2 and provide new clues to understand the specification of trophectoderm in vivo.

猪瘟E2基因工程亚单位疫苗能诱导机体产生抗CSFV中和抗体,被认为是最具应用前景的新型猪瘟疫苗.本研究利用稳定表达重组CSFV E2蛋白的细胞系HEK-293T-E2,制备E2亚单位疫苗并在动物体内检测其免疫原性.结果 显示,制备的E2亚单位疫苗能成功诱导试验兔和仔猪产生抗CSFV抗体,相比对照组,试验动物能够抵抗猪瘟标准强毒石门株的攻击,并且没有产生体温升高及其他不良反应,证实了该疫苗的有效性和安全性.本研究为新型猪瘟亚单位疫苗的研发提供了重要线索.

[目的]从临床发病的疑似感染鸡呼肠孤病毒的白羽肉鸡病料中分离鉴定获得1株鸡源呼肠孤病毒SD 18,对SD18株进行致病性及传播特性研究,为该病毒的深入研究和综合防治奠定基础.[方法]无菌采集疑似感染鸡呼肠孤病毒发病鸡跗关节处的肌腱和渗出物,分离病原物,在LMH细胞上培养,并连续盲传3代,经无菌生理盐水倍比稀释,采用Reed Muench法测定病毒鸡胚半数致死量(ELD50)和组织细胞半数感染量(TCID50);对分离毒株进行理化特性和血凝特性测定;利用设计的鸡呼肠孤病毒L1和S1基因特异性引物,对提取的病毒总RNA进行RT-PCR扩增,经PCR鉴定为阳性的菌落进行基因测序以及核苷酸同源性比对和系统遗传进化分析;用该分离株病毒对SPF鸡和白羽肉鸡进行动物回归试验,并用酶联免疫吸附试验(ELISA)测定攻毒后的SPF鸡血清中呼肠孤病毒抗体滴度.[结果]从疑似感染鸡呼肠孤病毒发病鸡跗关节处的肌腱和渗出物中分离获得1株鸡源呼肠孤病毒SD 18,其ELD50为10-6.5/0.1 mL,TCID50为10-7.36/0.1 mL.RT-PCR结果显示,目的基因片段长度分别为1 100,750,265bp,依次为鸡呼肠孤病毒的S1、σC和L1基因片段.核苷酸同源性比对结果显示,该分离株SD18与Ⅴ群鸡源呼肠孤病毒TW-918(台湾株)的S1基因序列同源性达92.7％,与工群鸡病毒性关节炎疫苗S1133株的同源性仅为59.0％.核酸序列遗传进化分析表明,该分离株SD18与Ⅴ群鸡源呼肠孤病毒TW-918(台湾株)处于同一进化分支上,与Ⅰ群鸡源呼肠孤病毒S1133株处于不同的进化分支上,说明新分离的肉鸡呼肠孤病毒SD 18株属于基因Ⅴ群,可能是Ⅰ群经典鸡源呼肠孤病毒S1133株的变异毒株.SPF鸡和白羽肉鸡回归试验表明,SD18株病毒能够引起鸡病毒性关节炎,与临床发病一致,并能水平传播.接种试验表明,病毒SD18能致死鸡胚,打开死亡鸡胚可见其绒毛尿囊膜增厚、尿酸盐沉积、胚体出血等症状,符合呼肠孤病毒的致病特点.[结论]该分离株SD18为新型肉鸡呼肠孤病毒,能够引起鸡发生病毒性关节炎.

Aims The outer membrane porin protein (OMPP) of Bordetella bronchiseptica is an important adhesion factor and protective immunogen. The aim of this study was to verify the immunogenicity of recombinant OMPP and its protective efficacy against a lethal challenge with B. bronchiseptica in rabbits. Methods and Results Soluble rOMPP was successfully expressed in Escherichia coli, and the purified recombinant protein was mixed with the ISA 201 VG adjuvant to prepare a subunit vaccine for B. bronchiseptica. Rabbits were immunized with the rOMPP subunit vaccine and then infected with the virulent B. bronchiseptica strain QDBb01. Rabbits immunized with the subunit vaccine were completely protected compared to the control group, and the protective effect was obviously better than that of the inactivated whole-cell vaccine. Moreover, analysis of the immunization duration showed that the rOMPP subunit vaccine provided immune protection for at least 4 months after the second immunization. Conclusions The rOMPP subunit vaccine completely protected rabbits from a subsequent B. bronchiseptica challenge. Significance and Impact of the Study The results will provide key information for the development of a safe and effective recombinant subunit vaccine against B. bronchiseptica in rabbits.

Background The cocirculation of duck hepatitis A virus subtypes 1 (DHAV-1) and 3 (DHAV-3) in ducklings has resulted in significant economic losses. Ducklings with DHAV-1 or DHAV-3 infection show similar clinical signs and gross lesions; hence, it is important to identify the viral subtypes in infected ducklings as early as possible for better clinical management. Methods and results Based on multiple 5' noncoding region (5'-NCR) sequences of DHAV-1 and DHAV-3 strain alignments, universal and type-specific primers were designed and synthesized. With three primers in one-tube reverse transcription-PCR (RT-PCR), reference DHAV-1 and DHAV-3 isolates ranging over 60 years and across many different countries were successfully amplified, indicating that the primer sequences were completely conserved. The sequence results and the sizes of amplicons from reference DHAV-1 and DHAV-3 isolates are completely correlated with their subtypes. Moreover, with this one-tube RT-PCR system, amplicon sizes from liver samples of reference DHAV-1- or DHAV-3-infected birds fit closely with their subtypes, which was determined by virus isolation and neutralization testing. No other duck-origin RNA viruses were detected. The sensitivity of viral RNA detection was 10 pg. With this system, 20% subtype 1, 45% subtype 3, and 9% coinfection of two subtypes were detected in 55 clinical samples. Conclusions and significance This novel approach could be used for rapidly typing DHAV-1 or DHAV-3 infection in routine clinical surveillance or epidemiological screening.

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a typical neurotropic coronavirus that mainly invades the central nervous system (CNS) in piglets and causes vomiting and wasting disease. Emerging evidence suggests that PHEV alters microRNA (miRNA) expression profiles, and miRNA has also been postulated to be involved in its pathogenesis, but the mechanisms underlying this process have not been fully explored. In this study, we found that PHEV infection upregulates miR-142a-3p RNA expression in N2a cells and in the CNS of mice. Downregulation of miR-142a-3p by an miRNA inhibitor led to a significant repression of viral proliferation, implying that it acts as a positive regulator of PHEV proliferation. Using a dual-luciferase reporter assay, miR-142a-3p was found to bind directly bound to the 3’ untranslated region (3’UTR) of Rab3a mRNA and downregulate its expression. Knockdown of Rab3a expression by transfection with an miR-142a-3p mimic or Rab3a siRNA significantly increased PHEV replication in N2a cells. Conversely, the use of an miR-142a-3p inhibitor or overexpression of Rab3a resulted in a marked restriction of viral production at both the mRNA and protein level. Our data demonstrate that miR-142a-3p promotes PHEV proliferation by directly targeting Rab3a mRNA, and this provides new insights into the mechanisms of PHEV-related pathogenesis and virus-host interactions.

为了解山东省不同地区猪群中猪瘟病毒(CSFV)分子流行病学特点,采用RT-PCR方法,对2012—2018年收集到的79份临床疑似猪瘟病例组织样品,进行E2基因主要抗原区域扩增与序列测定,对获取的59个CSFV E2基因主要抗原区域序列进行遗传演化分析,并构建了遗传发育进化树.结果显示:7株CSFV属1.1亚型,其中有3个毒株的E2基因与疫苗株E2基因几乎一致,提示这7个毒株可能来自疫苗毒或为类疫苗毒株;SDJZ-15株归属2.1b亚型,其E2基因推导氨基酸仅A51(丙氨酸)突变为V51(缬氨酸);其他51个毒株属2.1d亚型,与2型CSFV的E2基因主要抗原区(28～90 aa)氨基酸序列相比发生了4处突变,总体保持稳定.研究结果表明,2.1亚群中的2.1d分支CSFV是山东省当前的优势流行毒株.

经形态观察、培养特性、生化特性、PCR鉴定及PCR分型等鉴定,确定2018年从河南省某蛋鸭场分离到的一株疑似多杀性巴氏杆菌菌株为1:A型.采用药敏纸片,对该分离菌株进行药敏试验,发现其对头孢噻肟、头孢曲松钠、左氧氟沙星高度敏感,对强力霉素、环丙沙星、头孢哌酮舒巴坦钠、丁胺卡那中度敏感,对氟苯尼考、林可霉素不敏感.用该菌株的培养物腹腔注射4只体质量为25 g左右的昆明小鼠进行毒力试验,结果攻毒菌量为3.7 CFU时,能使全部小鼠死亡,证明该菌株具有较强的毒力.本研究对于了解河南省鸭源多杀性巴氏杆菌的血清型及其耐药性和致病性提供了数据支撑.

为跟踪传染性支气管炎病流行情况,2015年我们从在江苏某养鸡场疑似传染性支气管炎发病鸡群采集分离到1株疑似传染性支气管炎病毒,对其进行了鉴定和生物学特性研究.结果在鸡胚上连传6代出现鸡胚典型病变,死亡鸡胚全身出血明显,未死鸡胚发育受阻,呈明显的侏儒胚、蜷缩.分离株S1基因RT-PCR扩增可见到清晰的1.7 kb左右大小的条带,与引物设计的预期结果相符,与GenBank中的IBV序列进行比对和分析,从进化树看,分离株属于IBV当前主要流行的Qx型.电镜下观察可见直径为80 ～ 120 nm,有囊膜和纤突的冠状病毒粒子;经卵磷脂酶C处理后能凝集鸡红细胞,并能特异性地被该分离株的高免血清所抑制;对热、酸碱、胰酶有一定耐受性,对脂溶剂敏感,符合鸡传染性支气管关病毒(IBV)有囊膜的特性;该分离株的最小致病量为102.0EID50.该毒株灭活苗0.25 mL/只免疫即可达到良好的免疫效果.以上结果表明,该分离株符合鸡传染性支气管炎病毒的特性.