共查询到20条相似文献，搜索用时 406 毫秒
1.
为了评价猪繁殖与呼吸综合征病毒(PRRSV)不同分离毒株致病性差异,选择4株PRRSV分离毒株,即YX0907、BB0907、SY0909(属于NSP2基因亚型Ⅰ,具有30aa缺失特征)和NT0801(属于NSP2基因亚型Ⅱ,其NSP2上不存在缺失)进行动物接种试验。将23头45日龄PRRSV、猪圆环病毒2型和副猪嗜血杆菌阴性健康仔猪随机分为5组,第1～4组各5头猪,分别颈部肌内注射上述4株PRRSV分离株(均为第3代)2×104.32TCID50.(mL.头)-1,第5组3头猪作为空白对照,隔离饲养21d,每天观察临床症状。攻毒后不同时间测定病毒血症,并对死亡猪和第21天处死猪进行病理剖解、观察大体病理变化和组织病理变化。结果显示,BB0907毒株毒力最强,试验猪感染后体温明显升高,临床症状明显,可引起3/5死亡,病猪肺脏组织具有明显病理变化;YX0907毒株毒力较强,试验猪临床症状和病理变化明显,可引起2/5死亡;NT0801毒力较弱,部分试验猪感染后出现1～2d体温升高和轻度临床症状,未引起死亡;SY0909毒株毒力最弱,感染猪出现1～3d体温升高,临床症状不明显,病理变化较轻;而对照猪无临床异常表现和... 相似文献
2.
本试验旨在探究猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus, PRRSV)感染对仔猪肺、肠道中的菌群影响以及肺和肠道的组织学变化。试验选取35日龄断奶健康仔猪14头，适应性饲养7 d,随机分为感染组(n=7)和对照组(n=7),感染组仔猪接种2 mL 1×105 TCID50·mL-1PRRSV-JTS毒株病毒液，对照组仔猪接种2 mL DMEM培养基。感染组3头仔猪分别于10、12和19 d死亡，将存活的感染组与对照组仔猪于21 d后处死，并取肺、不同肠段组织样品以及肠道内容物。采用免疫组化染色和HE染色观察肺和肠道组织病理学变化，并基于16S rRNA基因的高通量测序分析仔猪肺和各肠段菌群结构。结果表明，感染组仔猪肺部和肠道均有病毒分布；与对照组仔猪相比，感染组仔猪肺部和肠道均存在明显的炎症反应。微生物组成结构及多样性分析显示，感染组仔猪Chao1、ACE指数在肺中上升，在仔猪各肠段中下降，Shannon、Simpon指数在肺中升高，在... 相似文献
3.
《中国畜牧兽医》2018,(11)
本研究旨在获得猪流行性腹泻病毒(PEDV)分离株,并对其致病性进行研究。应用Vero细胞从山东某猪场腹泻病料中进行病毒分离,通过细胞病变、免疫荧光试验、电镜观察和RT-RCR进行鉴定,并对分离株的S基因序列进行分析;应用10~(3.5) TCID_(50)/mL分离株口服接种3日龄仔猪并观察临床症状和病理变化;用不同滴度的分离株分别口服接种3日龄仔猪(3mL/只),统计各组仔猪的死亡率,确定最小致死量。结果显示,成功分离到1株PEDV,命名为PEDV SD201604株。该分离毒株能在Vero细胞上增殖,产生细胞病变,传代至F6代时病毒滴度可达10~(3.5) TCID_(50)/mL,免疫荧光试验和RT-RCR检测均为PEDV阳性。电镜观察可见直径大小约为100nm的病毒粒子,有明显的囊膜和纤突,具有PEDV病毒粒子典型的形态特征,确定分离株为PEDV。S基因序列分析显示,分离株为国内流行的PEDV变异株。动物回归试验结果显示,口服感染该分离株的5头3日龄仔猪全部出现典型的PED临床症状和病理变化,其中3头死亡。最小致死量试验结果表明,口服感染3 mL病毒含量为10~(4.5) TCID_(50)/mL的分离株可使仔猪全部死亡。本试验结果可为PEDV的分离鉴定及生物学研究提供参考与借鉴。 相似文献
4.
猪圆环病毒和猪繁殖与呼吸综合征病毒混合感染对仔猪致病性的评估 总被引：11，自引：0，他引：11
本研究通过猪圆环病毒2型(Porcine circovirus type 2,PCV2)和猪繁殖与呼吸综合征(Porcine reproductive and respiratory syndrome virus,PRRSV)强毒共感染3周龄健康仔猪来评价其致病性。试验动物随机分为3组,空白对照组(n=3头),PRRSV单独感染组(n=3头),PCV2和PRRSV共感染组(n=6头),从而比较相互之间的差异。通过临床症状、病理学变化、病原学和血清学检查,对二者混合感染仔猪的致病性进行了研究。结果表明PCV2和PRRSV共同感染能引起仔猪断奶后多系统消耗性综合征,表现为淋巴组织肿大、出血,肉芽肿性炎症,坏死性肝炎,仔猪消瘦、生长缓慢等特征性病变;混合感染能加重PRRSV对仔猪引起的间质性肺炎的严重程度。混合感染可以出现支气管肺炎和明显的肝病变,淋巴结多呈界限明显的块状出血等典型病变。 相似文献
5.
《中国兽医学报》2015,(11):1727-1734
本实验室2014年从福建省龙岩市某规模化猪场疑似猪伪狂犬病发病仔猪的脑组织中分离到1株猪伪狂犬病毒变异株,命名为PRV Fujian-LY株。为了研究Fujian-LY株对免疫仔猪的致病性,将8头20龄的PRV抗原、gE抗体均为阴性,gB抗体均为阳性仔猪随机分为3组,其中2组(每组3头猪)分别通过肌肉注射和滴鼻接种Fujian-LY株,第3组2头仔猪做阴性对照。试验仔猪接种病毒24h后体温均开始升高,随着病程发展,呼吸系统症状明显,滴鼻接种组仔猪发病明显快于肌肉注射组,所有攻毒仔猪虽均有发病但未出现死亡。通过病理剖检、PCR鉴定、病毒分离培养、易感动物感染试验及gE抗体ELISA检测证实Fujian-LY株人工攻毒试验成功。gE抗体检测结果表明所有攻毒仔猪攻毒后7dPRV gE抗体开始阳转。对发病仔猪剖检可见,脑积液明显增多,脑膜血管充血,并伴有出血等典型的伪狂犬病病理变化。病理切片观察结果显示发病仔猪脑实质中小血管扩张充血,血管周围有淋巴细胞包围"血管套"现象,其他主要脏器也均有明显的病理变化。试验结果表明PRV Fujian-LY株为伪狂犬病毒强毒株。 相似文献
6.
《动物医学进展》2021,42(7)
应用Vero细胞对江苏省某猪场腹泻病料进行病毒分离,通过细胞病变观察、RT-PCR扩增、动物回归试验对病毒进行鉴定,通过半数致死量测定病毒的致病性。结果显示,成功分离到1株猪流行性腹泻病毒(PEDV),命名为PEDV JS14株。该毒株在Vero细胞上盲传至4代出现细胞病变,主要表现为细胞面粗糙、颗粒增多,细胞多核呈空斑样,细胞脱落等病变特征;分离株口服感染5头7日龄仔猪全部出现典型的临床症状,其中4头死亡。F6代培养物以不同滴度口服接种15头7日龄的仔猪,其半数致死量为10~(5.0)TCID_(50)/mL。结果表明,本次分离的PEDV为强毒株,为进一步的生物学特性研究奠定了基础。 相似文献
7.
猪流行性腹泻病毒SD201604株的分离鉴定及致病性研究 总被引：2，自引：2，他引：0
本研究旨在获得猪流行性腹泻病毒（PEDV）分离株,并对其致病性进行研究。应用Vero细胞从山东某猪场腹泻病料中进行病毒分离,通过细胞病变、免疫荧光试验、电镜观察和RT-RCR进行鉴定,并对分离株的S基因序列进行分析;应用103.5 TCID50/mL分离株口服接种3日龄仔猪并观察临床症状和病理变化;用不同滴度的分离株分别口服接种3日龄仔猪（3 mL/只）,统计各组仔猪的死亡率,确定最小致死量。结果显示,成功分离到1株PEDV,命名为PEDV SD201604株。该分离毒株能在Vero细胞上增殖,产生细胞病变,传代至F6代时病毒滴度可达103.5 TCID50/mL,免疫荧光试验和RT-RCR检测均为PEDV阳性。电镜观察可见直径大小约为100 nm的病毒粒子,有明显的囊膜和纤突,具有PEDV病毒粒子典型的形态特征,确定分离株为PEDV。S基因序列分析显示,分离株为国内流行的PEDV变异株。动物回归试验结果显示,口服感染该分离株的5头3日龄仔猪全部出现典型的PED临床症状和病理变化,其中3头死亡。最小致死量试验结果表明,口服感染3 mL病毒含量为104.5 TCID50/mL的分离株可使仔猪全部死亡。本试验结果可为PEDV的分离鉴定及生物学研究提供参考与借鉴。 相似文献
8.
猪繁殖呼吸综合征病毒S3毒株的分离及其免疫特性研究 总被引：2，自引：0，他引：2
从某猪场仔猪体内分离到一株PPRSV毒株，该毒株能在Marc-145细胞上增殖产生致细胞病变，该病变能被PPRSV美洲型阳性血清所抑制，不被乙脑病毒、猪细小病毒、伪狂犬病毒阳性血清所抑制，经美洲型PPRSV荧光抗体染色呈阳性反应，电镜观察到直径55－60nm的病毒粒子，接种阴性仔猪未见临床症状异常，但抗体检测阳性。命名该分离毒为PPRSV－S3毒株。在S3弱毒株分离鉴定的基础上，进一步在猪体上对其致病性和免疫力进行研究。S3毒株接种仔猪后，仔猪不表现任何症状，也不向外排毒。4－5周龄的仔猪接种S3株后可产生坚强的免疫力，免疫后4－6个月能抵抗强毒攻击。后备母猪配种前2－3周免疫接种S3株，怀孕90－95d攻强毒，未发生流产、死胎、木乃伊胎、产弱仔等繁殖障碍现象。结果表明，S3是一株自然分离的弱毒株，且具有良好的安全性和免疫力。 相似文献
9.
10.
11.
12.
Cho JG Dee SA Deen J Guedes A Trincado C Fano E Jiang Y Faaberg K Collins JE Murtaugh MP Joo HS 《American journal of veterinary research》2006,67(3):489-493
OBJECTIVE: To evaluate the influences of animal age, bacterial coinfection, and porcine reproductive and respiratory syndrome virus (PRRSV) isolate pathogenicity on virus concentration in pigs. ANIMALS: Twenty-one 2-month-old pigs and eighteen 6-month-old pigs. PROCEDURE: Pigs were grouped according to age and infected with mildly virulent or virulent isolates of PRRSV. The role of concurrent bacterial infection was assessed by infecting selected pigs with Mycoplasma hyopneumoniae 21 days prior to inoculation with PRRSV. On alternating days, blood and swab specimens of nasal secretions and oropharyngeal secretions were collected. On day 21 after inoculation with PRRSV, selected tissues were harvested. Concentrations of PRRSV were determined by use of quantitative real-time PCR and expressed in units of TCID(50) per milliliter (sera and swab specimens) or TCID(50) per gram (tissue specimens). RESULTS: Concentrations of virus were higher in blood and tonsils of pigs infected with virulent PRRSV. Pigs infected with virulent PRRSV and M hyopneumoniae had significantly higher concentrations of viral RNA in lymphoid and tonsillar tissue. Coinfection with M hyopneumoniae resulted in a higher viral load in oropharyngeal swab specimens and blood samples, independent of virulence of the PRRSV isolate. Two-month-old pigs had significantly higher viral loads in lymph nodes, lungs, and tracheal swab specimens than did 6-month-old pigs, independent of virulence of the PRRSV isolate. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple factors affect PRRSV concentration in pigs, including pathogenicity of the PRRSV isolate, age, and concurrent infection with M hyopneumoniae. 相似文献
13.
Genetic variation analysis of porcine reproductive and respiratory syndrome virus isolated in China from 2002 to 2007 based on ORF5 总被引：5，自引：0，他引：5
Yufeng Li Xinglong Wang Ping Jiang Xiaofeng Wang Wen Chen Xianwei Wang Kewei Wang 《Veterinary microbiology》2009,138(1-2):150-155
The complete open reading frame 5 (ORF5) sequences of 34 field porcine reproductive and respiratory syndrome virus (PRRSV) isolates from China in 2002–2007 were detected and compared with the different variable Chinese isolates S1, CH-1a, HB-1, HB-2 and JXA1. The results showed that all isolates were of type 2 PRRSV and could be assigned to two clusters. The isolates in cluster sg1 was high similar with the highly pathogenic PRRSV strain JXA1, while sg2 clustered with type 2 PRRSV isolate VR2332. It was interesting that the isolate SH02 which was isolated from Shanghai in 2002 has 98.8% identity with JXA1 emerged in 2006. And the ZJJ07 isolate was found to be a natural recombinant between a Chinese highly pathogenic SY0608 isolate and a VR-2332 derivative NH04 isolate. Analysis of the potential glycosylation sites indicated that they were frequently mutated and formed five putative N-linked glycosylation (NGS) sites patterns based on N30, 33–35, 44 and 51 in those isolates. It indicated that the highly variable PRRSV strain with different NGS patterns spread widely in China. The great genetic diversity could be taken into consideration for the control and prevention of this disease. 相似文献
14.
从河北省保定某两个猪场疑似高致病性猪繁殖与呼吸综合征病料中分离出能引起Marc-145细胞病变的病毒,经RT-PCR鉴定证明,该病毒为美洲型PRRSV,分别命名为BD1和BD2株。并将其克隆、测序,与国内外PRRSV分离株的Nsp2和E基因序列进行了比较。结果表明,与PRRSV高致病性毒株JXA1、GD、WUH1、SY0608、HUN0701的核苷酸序列同源性为95.3%~96.5%,BD1和BD2株ORF5基因存在部分突变,没有缺失,与国内高致病性PRRSV分离株JXA1、HUB1、Jiangxi-3、Henan-1、WUH1的同源性高达97.2%~99.3%。 相似文献
15.
Martínez-Lobo FJ Díez-Fuertes F Segalés J García-Artiga C Simarro I Castro JM Prieto C 《Veterinary microbiology》2011,154(1-2):58-68
Porcine reproductive and respiratory syndrome virus (PRRSV) isolates are classified in two different genotypes, based on genomic heterogeneity: type 1, which comprises European type isolates, and type 2, which includes North American type isolates. It is believed that members of both genotypes differ in some biological properties including pathogenicity, however extensive studies comparing isolates of both genotypes have never been carried out. The objective of the present study was to compare the pathogenic properties of six different PRRSV isolates, three of type 1 and three of type 2, in a young pig infection model. For this purpose, a total of 105 3-week-old piglets were divided in 7 groups of 15 animals that were exposed on day 0 of the experiment to one of the six isolates tested or were mock infected (negative control group). Clinical signs and rectal temperatures were recorded daily and blood samples were taken on days 3, 6, 9, 12, 15, 18 and 21 of the experiment. On days 7, 14 and 21 post-inoculation five animals per group were sacrificed, macroscopic lung lesions were evaluated and different tissue samples were collected to determine viral organic distribution. The results obtained indicate that type 2 isolates are more pneumovirulent than type 1 isolates, as demonstrated by the recording of respiratory clinical signs only in pigs exposed to type 2 viruses and by the severity of macroscopic and microscopic lung lesions in those pigs. However, no clear differences could be established between genotypes in systemic clinical signs or viral load and viral distribution after challenge. These results support the general idea that type 2 isolates induce more severe respiratory disease than type 1 isolates. 相似文献
16.
犬2型腺病毒SY株的致弱驯化 总被引：1，自引：1，他引：0
作者对分离和系统鉴定的一株犬传染性喉气管炎病毒（犬2型腺病毒）SY（沈阳）株，用犬肾传代细胞MDCK进行了致弱驯化，每驯化15代做一次初步的犬的安全性试验。用大剂量不同代次病毒对易感犬进行人工感染试验，每天观察犬的临床症状及白细胞总数，并于接毒后的第5d安乐死，作病理解剖学和病理组织学检查，易感犬的感染试验结果表明，SY株在犬贤细胞上传15代时对犬的致病力已降低，30代时对犬已不引起发烧，精神沉郁和厌食等症状，仅引起轻度的鼻炎，中度的咽炎，剖检肺表现正常，仅见支气管淋巴结肿大，45代时无临床症状，剖检除扁桃体肿大外没有见到其它症状，60代毒已完全失去致病力，未见任何临床症状及病理变化。 相似文献
17.
Qiao S Feng L Bao D Guo J Wan B Xiao Z Yang S Zhang G 《Veterinary microbiology》2011,149(1-2):213-220
In 2006 China experienced outbreaks of a severe form of porcine reproductive and respiratory syndrome (PRRS) characterized by high fever, morbidity and mortality in swine irrespective of age. It is thought that secondary bacterial infections may contribute to the generation of this severe form of the disease. To determine the mechanisms by which a highly pathogenic PRRSV strain causes high fever we used an in vitro model to investigate the production of the pro-inflammatory cytokines IL-1β and TNF-α by macrophages in response to inoculation with PRRSV with or without LPS. Firstly we demonstrated, through an animal inoculation trial, that the isolate HN07-1 was a highly pathogenic strain and sequencing showed that the virus had the same genomic characteristics as previously described isolates. Porcine alveolar macrophage (PAM) cultures infected with PRRSV strains showed increased cytokine secretion and this was greater in the more virulent strain. Addition of LPS further increased cytokine secretion and again the effect was greater with the more virulent strain. Incubation of PAMs with PRRSV strain HN07-1 resulted in a significant increase in surface CD14 expression. This may explain the synergistic action between PRRSV and LPS in the induction of inflammatory cytokine secretion seen in the PAMs and so offer an explanation for the high fever that is characteristic of infections by the highly pathogenic PRRSV. 相似文献
18.
试验旨在探讨不同来源的传染性支气管炎病毒(Infectious bronchitis virus,IBV)诱导SPF鸡发病的免疫机制。选用140只1日龄SPF白来航鸡,随机分为4组,3组攻毒组通过滴鼻点眼途径分别接种鸡源IBV强毒株、鸡源IBV弱毒株和野鸡源IBV毒株3个毒株,对照组以同种方式接种等量灭菌的磷酸盐缓冲液。在感染后12 h、36 h、72 h、7 d和14 d,每组随机选取5只进行剖检,并分别采集法氏囊、肾脏和气管组织,剩余鸡用于观察临床症状、发病及死亡情况。应用实时荧光定量PCR检测攻毒后不同时间点采集的各组织中IBV的病毒载量、Toll样受体(Toll-like receptors,TLRs)及部分细胞因子(白细胞介素(interleukin,IL)和干扰素(interferon,IFN))表达量的变化。结果显示,感染不同来源IBV毒株之后仅鸡源IBV强毒株感染组SPF鸡出现抑郁、翅膀下垂、甩头等典型的临床症状,且在感染后5~10 d共有7只死亡,死亡率为20%。病理剖检发现,感染鸡源IBV强毒株的鸡肾脏肿大、尿酸盐沉积和有花斑样病变,而感染野鸡源IBV毒株、鸡源IBV弱毒株和对照组的鸡无明显的眼观病变。实时荧光定量PCR结果显示,在鸡源IBV强毒株组的法氏囊、肾脏和气管3个组织中均检测到病毒。对照组和野鸡源IBV毒株组中均未检测到病毒,鸡源IBV弱毒株组只在部分组织中检测到病毒。在感染后72 h,鸡源IBV强毒株组与其他各组相比,TLR1、TLR2、TLR3、TLR5、TLR7和TLR15基因在法氏囊中的表达量均显著升高(P<0.05),IL-6和IFN-β参与更强烈的抗病毒免疫反应;在感染后7 d,鸡源IBV弱毒株组与其他各组相比,肾脏中TLR2、TLR3、TLR15、TLR21、IL-6和IL-18基因表达量均显著升高(P<0.05)。野鸡源IBV感染后36 h法氏囊组织中IFN-γ基因表达量显著上调(P<0.05)。综上所述,3个IBV毒株中仅鸡源IBV强毒感染引起SPF鸡典型临床发病症状与可视组织病变,且可提高SPF鸡组织中免疫相关因子的基因表达量。本研究结果揭示,不同来源的IBV对SPF鸡的不同致病性与其感染诱导的免疫反应不同有关。 相似文献
19.
20.
Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoculation. R. equi was isolated from the feces and tracheal washings of the foal from 14 to 28 days after inoculation. The foal infected with 10(6) cells of A5 showed no clinical signs, and no R. equi was isolated from any of the samples of feces or tracheal washings during the 28 days of observation. Two foals of 45 and 50 days of age were infected with 10(5) or 10(6) of virulent R. equi ATCC 33701 having 15-17kDa surface proteins designated VapA. Both exhibited severe clinical signs (pyrexia, depression and anorexia) at 12 and 13 days after inoculation. Histopathological examination revealed that strain A5 caused focal granulomatous pneumonia in the foals. R. equi IMV strain A5 was isolated from lung lesions of both foals and from the contents of the intestinal tracts of the foal infected with 10(9) bacteria. These results suggest that IMV R. equi having VapB is less virulent than virulent R. equi having VapA in foals. This finding supports our previous results on the pathogenicities of R. equi strains having these virulence-associated antigens assessed by mouse pathogenicity tests. 相似文献