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1.
Turkey viral hepatitis (TVH) was experimentally reproduced in two experiments in 1-day-old poults. In the first experiment, an infectious inoculum was prepared from filtered yolk materials harvested from dead embryonating chicken eggs (ECE) previously inoculated with suspensions of liver and pancreas tissues collected from TVH-affected birds in commercial turkey flocks. One-day-old poults given a yolk-sac inoculation or oral gavage with this preparation developed lesions in the liver and pancreas characteristic of TVH at 20 days postinoculation (PI) in 60% and 14% of the experimentally infected birds, respectively. With the identical inoculum, embryo mortality occurred at 8 and 10 days PI in embryonating turkey eggs (ETE) inoculated into the yolk sac. In the second experiment, an infectious inoculum was prepared from filtered yolk materials from dead ETE harvested in the first experiment. One-day-old poults given a yolk-sac inoculation with this filtered yolk material developed lesions in the liver and pancreas within 5 days PI. At 20 days PI, 67% of the experimentally infected birds had similar lesions. With the inoculum given to these poults, embryo mortality occurred at 6, 8, and 10 days PI in ETE inoculated into the yolk sac. Virus particles 26-28 nm in diameter with icosahedral morphology typical of picornaviruses were identified by EM in the yolk sacs of ETE that died in both experiments, and inoculated ETE that died following passage of filtered suspensions of pancreatic tissues collected from affected birds in the first experiment.  相似文献   

2.
Uptake, transfer to rough endoplasmic reticulum, and intracellular growth of Brucella abortus were studied in Vero cells treated with endocytic and metabolic inhibitors. Infection of Vero cells was suppressed when inhibitors of energy metabolism (iodoacetate, dinitrophenol), receptor-mediated endocytosis (monodansylcadaverine, amantadine, methylamine), or endosomal acidification (chloroquine, ammonium chloride, monensin) were added to the inoculum. Inhibition was not observed when these drugs were added after the inoculation period. Infection of Vero cells by B abortus was inhibited by dibutyryl-cyclic adenosine monophosphate and Vibrio cholerae enterotoxin, but was stimulated by dibutyryl-cyclic guanosine monophosphate and escherichia coli heat-stable enterotoxin a. Uptake of B abortus by Vero cells was not prevented by colchicine, but was abolished by cytochalasin B. Uptake of heat-killed B abortus and noninvasive E coli was similar to that of viable brucellae. Intracellular growth of B abortus was not affected by cycloheximide. Results indicate that: B abortus may be internalized by a receptor-mediated phagocytic process; transfer of B abortus from phagosomes to rough endoplasmic reticulum may require endosomal acidification; and replication of B abortus within the rough endoplasmic reticulum may not depend on protein synthesis by the host cell.  相似文献   

3.
将布氏杆菌分不同剂量皮下注射接种于健康牛,于接种后45 d剖杀,采集相关的器官组织制备组织切片,应用免疫组化方法检查细菌在牛体内的分布。结果显示,肝脏、脾脏、肾脏、淋巴结出现强阳性信号;在高剂量注射的牛体内,肺脏、颌下淋巴结出现阳性细胞;心脏和健康牛组织呈阴性反应。阳性信号主要位于感染细胞的胞质中,偶尔出现在细胞核内。  相似文献   

4.
Chicken embryo propagation of type I avian adenoviruses   总被引：2，自引：0，他引：2  
B S Cowen 《Avian diseases》1988,32(2):347-352
Forty-two clone-purified, cell-culture-propagated type I avian adenoviruses (AAV) representing 11 serotypes and two intermediate strains were evaluated for virus replication (evidenced by embryo death and lesions) resulting from the inoculation of specific-pathogen-free chicken embryos via the chorioallantoic sac or yolk sac. Commonly observed embryonic changes were death, stunting and curling, hepatitis, splenomegaly, congestion and hemorrhage of body parts, and urate formation in the kidneys. Basophilic or eosinophilic intranuclear inclusion bodies characteristic of fowl adenoviruses were observed in hepatocytes. The magnitude and relative uniformity of intra- and interserotypic embryo mortality, gross lesions, and virus titers was greater in embryos inoculated via the yolk sac. This work identifies the yolk sac as a practical and sensitive chicken embryo inoculation route for poultry diagnosticians to employ. It is suggested that the yolk sac may be a reliable alternative to cell culture for the successful isolation of all type I avian adenoviruses.  相似文献   

5.
Vero cells were inoculated with the six species of Brucella (B. abortus, B. melitensis, B. suis, B. neotomae, B. canis, and B. ovis) and examined by fluorescence and electron microscopy. All Brucella spp. were internalized by Vero cells. In all cells except those inoculated with B. canis, the numbers of intracellular brucellae increased with time after inoculation. Intracellular brucellae were first seen within phagosomes and phagolysosomes. Subsequent localization within cisternae of the rough endoplasmic reticulum was seen with all species of Brucella, except B. canis, which was restricted to phagolysosomes. Although rough brucellae were more adherent and entered a greater number of Vero cells, intracellular replication occurred in a larger percentage of cells with smooth rather than with rough brucellae. These results suggest that phagocytosed Brucella spp. are transferred 1) to cisternae of the rough endoplasmic reticulum, where unrestricted bacterial replication takes place; or 2) to phagolysosomes in which Brucella spp. fail to replicate. The various strains of Brucella spp. differ in their ability to induce their own transfer to the rough endoplasmic reticulum.  相似文献   

6.
We examined the susceptibility of late-stage chicken embryos to infection with oncogenic serotype 1 Marek's disease virus (MDV 1). Intravenous inoculation of MDV 1 at embryonic day (ED) 16 resulted in significant replication of the virus in embryonic tissues. Within 5 days of virus exposure, pp38 viral antigen (pp38) was detected in embryonic bursae and MDV 1 was isolated by plaque assay from the spleens, thymuses, and bursae of embryos. The pathogenesis of MDV 1 after intravenous inoculation at ED 16 was similar to that in chicks exposed to MDV 1 after hatching. In contrast to the response of the embryo to intravenous inoculation, embryos exposed to MDV 1 by the amniotic route did not develop detectable pp38, nor could the virus be isolated from the embryonic tissues by plaque assay. These results show that the route of inoculation of MDV 1 in the embryos is critical for allowing the virus to come in contact with target cells.  相似文献   

7.
Pregnant goats were given Brucella abortus intravenously or in uterine arteries, and tissues from the uterus and placentae were examined at various post-inoculation intervals to study mechanisms of placental infection. Placentitis was present by 5 days post-inoculation and abortions occurred within 11 days. B. abortus was identified in placentae by light microscopy and immunoperoxidase techniques. B. abortus was first seen in erythrophagocytic trophoblasts of the placentome. Subsequently, high numbers of B. abortus were seen in periplacentomal chorioallantoic trophoblasts. Trophoblast necrosis, chorioallantoic ulceration, and large numbers of B. abortus in chorionic villi were present in later stages of infection. These results suggest that entry and replication of B. abortus in trophoblasts precede placentome and fetal infection and that trophoblasts are the source of B. abortus for these tissues. Experimental caprine brucellosis closely resembles bovine and ovine brucellosis and it provides a model to study the intracellular development of B. abortus in trophoblasts.  相似文献   

8.
Pregnant heifers were exposed by a conjunctival inoculation with 1 X 10(7) colony-forming units of Brucella abortus strain 2308. At parturition, milk and uterine samples from dams plus samples from dead calves were cultured bacteriologically for Brucella. The logistic regression probability of B abortus isolation increased from 0.22 to 0.90, as fetal age at exposure of heifers increased from 60 to 150 gestation days. Strain 2308 was recovered at parturition from 14 (64%) of 22, 17 (71%) of 24, and all 28 (100%) heifers that were at gestation days less than 127, 127 to 157, and greater than 157, respectively, at time of exposure. The number of infected heifers and the number of samples positive for B abortus were significantly increased as fetal age at exposure of heifers increased from gestation days less than 127 to greater than 157 (chi 2 greater than 10, P less than 0.005).  相似文献   

9.
Intestinal tissues obtained from coronavirus-infected embryos and turkeys were examined by fluorescent antibody tissue section technique (FAT). Evidence of viral antigen was demonstrated in the cytoplasm of the intestinal epithelial cells covering the villi. Embryo intestines that were examined from 24 to 96 hours after inoculation were positive for immunofluorescence (IF), whereas bursa of Fabricius was negative. Poults hatched from infected embryos were examined at 2 days of age and were positive for IF. Coronaviral antigen was detected by FAT in the cytoplasm of intestinal epithelial cells of the jejunum, ileum, duodenum, and cecum in all turkeys that were examined from 24 hours to 28 days.  相似文献   

10.
The protective properties of the monoclonal antibody ISS/32 anti-B. abortus were estimated by splenic infection with B. abortus 544. Five groups of Balb/c mice were used: two groups, previously vaccinated with a 45/20 antigen and a-LPS antigen, were challenged after 30 days intravenously by inoculation of 2.10(5) cells of B. abortus 544, one group was challenged with the same dose of B. abortus 544 preincubated with MAb-ISS/32 and another one with B. abortus 544 incubated with negative serum; the fifth group infected with B. abortus 544 only served as control. The results, expressed as an index of splenic infection, show significant protective properties of monoclonal antibody ISS/32. The infection index in the MAb-ISS/32 group of mice was a bit lower than in B. abortus 45/20 vaccine group.  相似文献   

11.
Chick embryos infected with Akabane virus by the yolk sac route at 6 days of incubation developed polymyositis and encephalitis. At 3 to 7 days after inoculation, skeletal muscles had myotubule degeneration, clumping of muscle cell nuclei, and infiltration of heterophils; dysplasia and aplasia were evident at 9 to 15 days after inoculation. Changes in the cerebral neostriatum and optic lobes at 2 to 11 days after inoculation included necrosis of primordial nervous tissue, hemorrhages, and hyperplasia of the vascular endothelial cells. Cavities were in nervous tissue subsequent to encephalitis. Hydranencephaly and vascular wall thickening were found 13 and 15 days after inoculation. Embryos infected intravenously at 15 days incubation had foci of encephalitis 3 to 6 days after inoculation, including neuronal degeneration, neuroglial hyperplasia, vascular endothelial proliferation, and heterophil infiltration.  相似文献   

12.
Twenty-four 70-week-old and sixteen 27-week-old white leghorn hens were challenged with R strain Mycoplasma gallisepticum (MG) by injection into the caudal thoracic air sac and infraorbital sinus. Eggs were collected daily and cultured within 7 days or incubated for 18 days. Vitelline membranes of eggs were cultured directly; in 18-day-old embryos, cultures were taken from the yolk sac, air sacs, and oral cavity. Culture of vitelline membrane of eggs within 2 days was compared with culture of eggs stored 10 days post oviposition. The first MG-positive egg was laid 2 days postinfection (PI). Hens continued to lay positive eggs to the end of the experiments. There was no significant difference in MG recovery between eggs cultured within 2 days and those cultured 10 days post oviposition. MG was isolated at a significantly higher rate from eggs than from 18-day-old embryos. MG was isolated at a higher rate from the yolk sac of 18-day-old embryos than from the air sacs or oral cavity of the same embryos.  相似文献   

13.
J M Sharma 《Avian diseases》1987,31(3):570-576
Several oncogenic and non-oncogenic isolates of Marek's disease virus (MDV) were inoculated into embryonated eggs on embryonation day (ED) 16 to 18, and embryos or chicks hatching from inoculated eggs were examined for infectious virus and viral internal antigen (VIA) in lymphoid organs. There was no evidence of extensive replication of MDV in any of the embryonic tissues examined. Levels of VIA peaked 4-5 days after chicks hatched. This indicated that MDV remained inactive during embryonation and did not initiate pathogenic events until chicks hatched. Because HVT replicated rapidly in the embryo but MDV did not, in ovo inoculation of HVT simultaneously with oncogenic MDV or several days after MDV resulted in significant protection (P less than 0.025) of hatched chicks against Marek's disease (MD). Little protection was obtained if HVT was given simultaneously with MDV or after MDV to chicks already hatched. The relative susceptibility of the embryo to extensive replication of the vaccine virus but not the challenge virus apparently accounted for protection against MD in chicks hatching from dually infected eggs.  相似文献   

14.
J M Sharma 《Avian diseases》1986,30(4):776-780
Vaccination of specific-pathogen-free chickens as 18-day embryos with the BVM isolate of infectious bursal disease virus (IBDV) resulted in extensive replication of the vaccine virus in the embryonic tissues. The virus was recovered from lung, thymus, proventriculus, liver, kidney, and spleen of embryos 1 day postvaccination, and recoverable virus persisted for at least 7 days. Replication and spread of the vaccine virus in chickens vaccinated as 18-day embryos was compared with that in chickens vaccinated at hatch. Distribution of the virus in tissues was more extensive, virus levels in tissues were generally higher, and detectable virus persisted longer in chickens vaccinated as 18-day embryos than in those vaccinated at hatch. Effective vaccine response could be initiated with 6.2 median embryo lethal doses, the lowest dose tested. Chickens immunized as embryos developed neutralizing antibody against IBDV and resisted challenge with pathogenic IBDV at 4, 6, 8, and 10 weeks of age.  相似文献   

15.
Change of porcine circovirus 2 (PCV2) target cells during development from fetal to postnatal life in pigs was examined. PCV2 inoculation was performed in fetuses in utero at either 57, 75 or 92 gestational days and in piglets at 1 day of age. Twenty-one days after virus inoculation, PCV2-infected cells in the heart, lungs, liver, spleen and inguinal lymph nodes were localized and immuno-phenotyped by double-immunofluorescence labeling using different cell markers and PCV2-antibodies. During fetal life, viral antigens were detected in cardiomyocytes, hepatocytes and macrophages and infected cell numbers decreased with increasing fetal age at inoculation. The heart contained the highest number of infected cells and cardiomyocytes were the main target cell. Postnatally, macrophages were the only target cell type in different organs and infected cell numbers were similar to those of fetuses inoculated at 92 days of gestation. One piglet showed exceptionally high number of infected cells in different organs with values 13-513-fold higher compared to littermates. In this piglet, the majority of infected cells in lymphoid tissues could not be typed. This study reveals that PCV2 target cells change from cardiomyocytes, hepatocytes and macrophages during fetal life to only macrophages postnatally.  相似文献   

16.
Brucella abortus (B. abortus) is a facultative intracellular pathogen that can survive inside macrophages and trophoblast giant cells, and the causative agent of brucellosis. In the present study, we found that production of regulated upon activation normal T-cell expressed and secreted (RANTES) due to B. abortus infection contributes to abortion in pregnant mice. B. abortus infected pregnant interferon-gamma (IFN-gamma) knockout mice died within 15 days of infection, but non-pregnant IFN-gamma knockout mice were still alive. With infection by wild type B. abortus, a large amount of RANTES production was observed in pregnant IFN-gamma knockout mice, and induction of RANTES was also observed in normal pregnant mice infected with the wild type, but not in those infected with the intracellular replication-defective mutant. Production of RANTES and IFN-gamma were inhibited in mice inoculated with the respective RANTES or IFN-gamma antibody. Neutralization of RANTES, induced by B. abortus infection, served to prevent abortion. These results indicate that the production and function of RANTES are correlated with IFN-gamma in pregnant mice infected with B. abortus.  相似文献   

17.
Inoculation of 6-day-old and 4-week-old chickens with pathogenic or attenuated avian reovirus resulted in an inapparent infection. The virus had a greater tissue distribution and persisted longer in tissues of 6-day-old chickens. Interferon was detected in only the serum and lung of infected chickens and appeared to be related to route of inoculation. Titers of interferon were greater and appeared sooner in the tissues of older chickens. Reovirus-neutralizing antibody was not detected in the serum of chickens of either age 120 days postinfection.  相似文献   

18.
旨在对我国流行的4种血清型(4、8a、8b和11型)禽腺病毒-I群(fowl adenovirus, FAdVs)对鸡胚和鸡的致病性进行研究,选取12日龄SPF鸡胚和10日龄SPF鸡感染4种血清型FAdVs,对SPF鸡胚和鸡的死亡率及鸡胚胚体质量进行统计;对感染鸡的大体剖检变化、组织学变化进行观察和病毒载量进行研究。结果显示,FAdV-8b和FAdV-11感染SPF鸡胚后其死亡率高于45%,FAdV-8a感染后胚体质量降低最严重,FAdV-4感染后对胚体质量影响最小;FAdV-4感染SPF鸡死亡率高达53.3%,其他组鸡无死亡;除肝出现肿胀、变性、出血和炎性细胞浸润外,4种病毒感染SPF鸡后分别造成不同组织器官的严重损伤,FAdV-4感染出现心包积液、FAdV-8a感染肌胃出现糜烂、FAdV-8b感染导致腺胃肿胀和FAdV-11感染导致胰腺坏死,各损伤组织均出现实质细胞坏死和炎性细胞浸润;4种病毒感染SPF鸡均出现免疫器官的组织学损伤,其中,FAdV-8a、-8b 和-11感染鸡引起的免疫器官内淋巴细胞缺失和损伤较FAdV-4更为严重;组织病毒载量结果显示,FAdV-4感染鸡心和肾病毒载量最高,FAdV-8b和FAdV-11感染鸡胰腺病毒载量高于FAdV-4感染组,且FAdV-4感染鸡心、肝和肾病毒载量在感染后第5天高于第3、7天,除FAdV-8a感染组外,病毒载量与各组织损伤情况相一致。综上表明,4种血清型FAdVs中,FAdV-11对SPF鸡胚的致死性最强,FAdVs对SPF鸡的致死率最高,尽管FAdV-8a、-8b 和-11不致死SPF鸡,但对SPF鸡胚、SPF鸡的消化系统和免疫系统损伤较为严重,这将会造成鸡胚孵化率降低、鸡生长发育缓慢和易于继发其他病原感染。  相似文献   

19.
本研究的病毒是从广东患病鹅的小肠组织中分离的,初步鉴定为小鹅瘟病毒(Goose parvovirus,GPV),命名为QY/05后,对病毒的生物学特性进行了鉴定。病料经过处理后,接种12日龄非免疫鹅胚,传代,发现病毒对鹅胚的平均致死时间为3～4d,胚体全身出现较为严重的出血点。病毒接种鹅成纤维细胞和番鸭成纤维细胞,显微镜下可见细胞圆缩、脱落、折光性增强等明显的细胞病变。鹅胚尿囊液经梯度离心后,磷钨酸负染,电镜下可见明显细小的病毒样粒子。这株小鹅瘟病毒尿囊液对鹅胚的EID50为10-3.67/0.3ml。对鹅胚成纤维细胞的TCID50分别为2-5.425/0.1ml。感染一个病毒最小致死量的鹅胚平均死亡时间(MDT)分别为96h。提取DNA后,PCR扩增,在阳性对照处扩增出需要的目的条带。研究结果表明,该分离毒株为典型的鹅细小病毒(Goose Parvovirus,GPV)。  相似文献   

20.
本研究利用血清Ⅰ型马立克氏病病毒（Marek＇s disease virus serotype 1,MDV-1）被膜蛋白UL11原核表达产物作为免疫原,免疫小鼠制备多抗血清,通过间接免疫荧光试验,结果发现：UL11真核表达时,存在于COS-1和Sf9细胞浆中。而检测MDV的RB1B毒株感染CEF时,却发现UL11高度聚集于空斑中心,且可分布于空斑周围的所有细胞核中。这为研究UL11细胞核内扩散的分子机制,以明确UL11是否参与MDV-1致瘤的过程提供了参考。  相似文献   

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