犬瘟热自然病例脱髓性脑病发生的机理

为了进一步调查脑组织的髓鞘脱失与神经胶质细胞等成份的关系,用12只犬瘟热自然病例通过病理组织学和免疫组织化学染色法进行了本试验.结果表明:髓鞘脱失部位的脑组织伴有明显的血液循环障碍,即淤血、水肿、血栓形成和弥漫性血管内凝血;少突胶质细胞发生代谢紊乱和凋亡;用抗犬瘟热病毒(CDV)抗体染色,星状胶质细胞呈现强阳性反应;用抗GFAP染色,纤维性星状胶质细胞在脱髓区呈较强阳性反应,用TUNEL染色可检出发生凋亡的星状胶质细胞;一些室管膜细胞也被CDV感染,许多含有包涵体币口凋亡的室管膜细胞在脑室壁被发现;少数神经元变性和皱缩,其核发生浓缩.据此认为,脑组织的髓鞘脱失主要与血液循环障碍和少突胶质细胞的代谢紊乱及凋亡有关;脑组织的髓鞘脱失是许多病因共同作用的结果,并非是一种病因所致.     

犬瘟热病

1病原 犬瘟热病毒（CDV）属于RNA病毒，大小为100～300nm，圆形体。该病毒可以在犬、雪貂和犊牛肾细胞以及鸡成纤维细胞中进行培养，在犬肾单层细胞培养中可生长繁殖，并形成多核体（合体细胞）及核内、胞浆内包涵体及星状细胞，还可以用鸡胚培养，接种1～2d，在绒毛尿囊膜上可以见到水肿，外胚层细胞的增生和部分坏死。     

自然感染犬瘟热病毒小熊猫的病理学观察

对自然感染犬瘟热病毒的小熊猫进行了系统的病理学观察。结果表明，犬瘟热病毒对小熊猫内脏器官可造成广泛性损伤。在淋巴系统各器官(淋巴结、脾等)表现为变性、坏死、淋巴细胞减少等退行性变化；肺表现为浆液性-化脓性肺炎；胃肠道表现为卡他性炎；脑表现为非化脓性脑炎；同时在支气管上皮细胞、肺泡壁上皮细胞、食管上皮细胞、肠上皮细胞、胆囊上皮细胞、肾小管上皮细胞和膀胱上皮细胞等胞浆内出现嗜酸性包涵体。     

中西医结合治疗犬瘟热

犬瘟热是由犬瘟热病毒引起的一种热性、高度接触性、致死性传染病。犬瘟热病毒为副黏病毒科麻疹病毒属成员,为单股RNA病毒,具有泛嗜性,对上皮细胞有特殊亲和力,常侵害黏膜上皮细胞、网状细胞、白细胞、神经胶质细胞和神经元。核内包涵体多位于被覆上皮细胞、腺上皮细胞和神经节细胞。因此病犬常表现结膜炎、鼻炎、气管支气管炎和卡他性肠炎、鼻镜和脚垫角质化、淋巴免疫系统被破坏、     

犬瘟热的微生物学诊断研究

对临床诊断为犬瘟热的１４例病犬，取其脑组织，运用细胞培养、合胞体检查、包涵体检查、免疫荧光试验、电镜观察等５种检测方法，就犬瘟热的微生物学诊断进行了系统的研究。结果表明，犬脑组织块与猫胚（ＦＥ）细胞或非洲绿猴肾（Ｖｅｒｏ）细胞共同培养，盲传的培养物出现不稳定的细胞病变，通过对不同代次的培养物检查包涵体，并作超薄切片或负染，电镜观察犬瘟热病毒（ＣＤＶ）粒子，证实分离到ＣＤＶ野毒。病犬脑组织切片经ＨＥ染色检查包涵体及用ＣＤＶ荧光抗体直接法检测脑抹片及接种犬脑的细胞培养物，均获得一定的阳性结果。建立的改良离子捕获电镜法，用于检测犬脑匀浆和犬脑接种细胞培养物，与离子捕获电镜法、免疫电镜法及直接电镜法相比，效果更为理想。１４例临床诊断为犬瘟热的病犬，综合运用上述微生物学手段检测，结果为１２例阳性，２例疑似。     

犬三大疫病的临床鉴别

犬瘟热病、犬细小病毒病、犬传染性肝炎病可称为犬的三大疫病。其对犬及犬类动物危害严重 ,往往引起死亡 ,给养殖业造成严重的经济损失。笔者根据多年的临床工作经验 ,将此三大疫病的临床特征归纳见表 1。表 1　犬三疫病的临床特征病名犬瘟热犬细小病毒病犬传染性肝炎病毒ＣＤＶ病毒ＣＰＶ病毒ＩＣＨＶ病毒体温Ｔ39.5℃～ 41℃Ｔ40℃以上或不高Ｔ40℃以上包涵体 核内胞浆包涵体胞浆为主肠上皮细胞内 ,核包涵体肝细胞内和内皮细胞内 ,核内包涵体年龄 4～ 1 2月龄发病率高幼犬多发各龄犬均发 ,幼犬多发季节冬季多发无明显季节性无季节性特征双…     

犬神经过度兴奋伴有消化功能紊乱疾病的鉴别与诊断

1传染病 犬瘟热、狂犬病、伪狂犬病、破伤风都属传染性疾病。犬瘟热病毒可在各种上皮组织、网状内皮系统、大小神经胶质细胞、中枢神经细胞等细胞浆和胞核中形成嗜酸性包含体。消化道黏膜出现卡他性炎症。幼犬有时表现出血性炎症，幼犬发病时出现明显的腹泻、呕吐。患犬所排粪便稀且红，气味恶臭。     

犬瘟热病

1病原犬瘟热病毒(CDV)属于RNA病毒,大小为100～300nm,圆形体.该病毒可以在犬、雪貂和犊牛肾细胞以及鸡成纤维细胞中进行培养,在犬肾单层细胞培养中可生长繁殖,并形成多核体(合体细胞)及核内、胞浆内包涵体及星状细胞,还可以用鸡胚培养,接种1～2d,在绒毛尿囊膜上可以见到水肿,外胚层细胞的增生和部分坏死.     

犬瘟热的治疗措施

犬瘟热(canine distemper)是犬瘟热病毒感染肉食兽中犬科(尤其是幼犬)鼬科及一部分浣熊科动物的高度接触传染病,致死性传染病.犬瘟热病毒(CDV)为单股RNA病毒,属于副黏科毒科,病毒呈圆形或不整形,有时呈丝状,直径为115~160nm,核衣壳呈螺旋状,外有囊膜,囊膜表面有囊膜粒.病毒侵入敏感细胞后,在胞浆和胞核内复制,并在胞浆或核内形成包涵体.犬瘟热病毒与麻疹病毒,牛瘟病毒之间存在共同抗原,能被麻疹病毒或牛瘟病毒的抗体所中和.犬瘟热病毒对乙醚和紫外线敏感.对低温干燥有较强的抵抗力.对多种消毒剂敏感.0.75%~3%甲醛,3%氢氧化钠和5%石炭酸等都有效杀灭病毒.     

犬瘟热病毒自然感染犬淋巴组织中T、B细胞变化的研究

为了调查患犬瘟热病犬淋巴组织中T、B细胞变化的特点及淋巴细胞减少的发病机制,试验通过免疫组织化学的方法观察了T细胞(用CD3和CD45RO检测T细胞)、B细胞(用IgG、IgM抗血清检测B细胞)和犬瘟热病毒(抗犬瘟热病毒抗体)在病犬淋巴组织中的分布。结果表明:在淋巴组织中的淋巴细胞、淋巴小结中树突状细胞和巨噬细胞中均检出了抗病毒阳性反应细胞。在骨髓组织的前髓细胞中也发现抗病毒阳性反应细胞和嗜酸性胞浆内及核内包涵体的存在。与对照组相比,CD3和CD45RO阳性细胞主要存在于T细胞的分布域;但CD3和CD45RO阳性T细胞的数量较少。位于淋巴组织中的巨噬细胞有的被CD45RO染成阳性。在B细胞分布的区域中,IgG、IgM阳性细胞的数量明显减少;一些位于淋巴组织的浆细胞也被IgG或IgM染成阳性。在淋巴组织中淋巴细胞减少的顺序为:IgG阳性细胞减少最明显,其次为IgM和CD45RO阳性细胞,再次为CD3阳性细胞。依据试验结果,作者认为病犬淋巴组织中淋巴细胞减少主要是由B细胞缺乏所引起的;淋巴细胞的增殖能力减弱是引起淋巴组织中淋巴细胞减少的重要原因。     

Central nervous system lesions caused by canine distemper virus in 4 vaccinated dogs

We examined the cerebellum and cerebrum of 4 vaccinated dogs, 3–60-mo-old, that displayed clinical signs of canine distemper virus (CDV) infection, and died 7–40 d after developing neurologic signs. The main histologic lesions were demyelination, gliosis, meningitis, perivascular lymphocytic cuffing, and inclusion bodies. These lesions were similar in all 4 cases regardless of the time since vaccination, except that meningoencephalitis and gliosis were subacute in 3 dogs and chronic in 1 dog. However, these differences did not appear to be related to their vaccination status. Immunohistologically, a CDV-positive immunoreaction was seen mainly in astrocytes, neurons and their axons, lymphocytes around and in the blood vessels of the pia mater and choroid plexus, ependymal cells of each ventricle, and the cells of the choroid plexus. The histologic and immunohistologic changes were similar in the cerebellum and cerebrum. The genetic characterization of the virus strains in 2 of these naturally occurring canine distemper cases confirmed that they were South American wild-type strains (Kiki and Uy251) belonging to the EU1/SA1 lineage. These strains are not included in the commercial CDV vaccines available in Uruguay.     

Immunohistochemical distribution of alpha B-crystallin in the cerebellum of dogs infected with canine distemper virus

The cerebella of 12 dogs infected with canine distemper virus (CDV) and those of three normal dogs were examined. The avidin-biotin-peroxidase complex technique was used to detect alphaB-crystallin (alphaB-c) immunoreactivity and immunolocalisation of the CDV antigen. CDV antigens, immunopositive astrocytes, oligodendrocytes and granular neurons were seen in both the white and grey matter of the infected dogs. In the controls, alphaB-c immunopositive glial cells were seen in the white matter and around the Purkinje cells. In dogs with distemper, alphaB-c immunoreactivity was not observed in some of the glial cells around the Purkinje cells. A significant negative correlation of P < 0.01 level was found between areas of severe demyelination and the number of alphaB-c immunopositive cells in dogs infected with CDV. Such correlation was not observed between mild and moderate demyelinating areas and alphaB-c immunostaining. The alphaB-crystallin/ total number of cells ratio was found to be significant in severely affected demyelinating areas (P < 0.05). These data indicate that there was a relationship between the degrees of CDV associated with demyelination and the level of alphaB-c expression in the glial cells.     

Atypical necrotizing encephalitis associated with systemic canine distemper virus infection in pups

This report describes the naturally occurring atypical neuropathological manifestation of systemic canine distemper virus (CDV) infection in two 16-day-old Pit Bull pups. CDV-induced changes affected the gray and white matter of the forebrain while sparing the hindbrain. Histologically, there was necrosis with destruction of the nervous parenchyma due to an influx of inflammatory and reactive cells associated with eosinophilic intranuclear inclusion bodies within glial cells. Positive immunoreactivity against CDV antigens was predominantly observed within astrocytes and neurons. RT-PCR was used to amplify CDV-specific amplicons from brain fragments. These findings suggest the participation of CDV in the etiopathogenesis of these lesions.     

Immunohistochemical demonstration of canine distemper virus antigen as an aid in the diagnosis of canine distemper encephalomyelitis

Brain tissue from 33 dogs with non-suppurative encephalitis was examined for evidence of canine distemper virus (CDV) encephalitis. Sections were examined for lesions, inclusion bodies, syncytial cells and CDV antigen using a double bridge unlabelled antibody enzyme technique. Histopathological lesions considered to be typical of granulomatous meningoencephalomyelitis were found in seven dogs. They all lacked inclusion bodies, syncytial cells and CDV antigen. The remaining 26 dogs all had histopathological lesions typical of CDV encephalitis. Inclusion bodies were found in 24 dogs, four of which also had syncytial cells and CDV antigen was detected immunocytochemically in 25. One dog had no inclusion bodies or syncytial cells and was immunohistochemically negative. Syncytial cells have been found to be of limited diagnostic value for the diagnosis of CDV encephalitis. While inclusion bodies proved to be a good diagnostic criterion for the confirmation of CDV infection, the immunohistochemical demonstration of CDV antigen proved to be superior. CDV antigen was more prevalent than inclusion bodies in tissue sections and much more easily detectable.     

Immunohistochemical investigation of cerebellum in dogs infected with canine distemper virus

The cerebella of 21 dogs with canine distemper virus (CDV) infection and four normal dogs were examined histopathologically and immunohistochemically. Cerebella of CDV-infected dogs showed nonsuppurative demyelinating encephalomyelitis, classified as acute, subacute or chronic. Immunolocalisation of CDV antigen also confirmed the infection. Tissues were examined for co-localisation of the CDV antigen with either an astrocyte-specific marker, glial fibrillary acidic protein (GFAP), or an oligodendrocyte-specific marker, galactocerebroside (GalC). Immunoreactive cells were counted in demyelinating areas of the white matter. The number of astrocytes (GFAP positive) was significantly (p < 0.05) higher in CDV-infected dogs compared to controls. In contrast, the number of oligodendrocytes (GalC positive) was significantly (p < 0.001) lower in CDV-infected dogs and was much lower in chronic cases (p < 0.05). Approximately 41% of astrocytes and 17% of oligodendrocytes were immunoreactive for CDV. The ratio of CDV-infected oligodendrocytes and astrocytes remained almost constant during the progression of the disease (P > 0.05). In conclusion, CDV infects both astrocytes and oligodendrocytes. The gradual loss of oligodendrocytes is most likely responsible for the progressive demyelination in CDV infection. Astrocytosis in CDV infection should be further investigated if it occurs to stimulate oligodendrocytes for myelin production to compensate for the loss or to induce oligodendrocyte degeneration.     

Canine microglial cells: stereotypy in immunophenotype and specificity in function?

Microglial cells represent the endogenous immune system of the central nervous system (CNS). Upon pathological insults they reveal their immunological potential aimed at regaining homeostasis. These reactions have long been believed to follow a uniform and unspecific pattern which is irrespective to the underlying disease entity. Evidence is growing that this view seriously underrates microglial competence as the defenders of the CNS. In the present study, microglial cells of 47 dogs were examined ex vivo by means of flow cytometry. Ex vivo examination included immunophenotypic characterization using eight different surface markers and functional studies such as phagocytosis assay and the reactive oxygen species (ROS) generation test. The dogs were classified according to their histopathological diagnoses in disease categories (controls, canine distemper virus (CDV) induced demyelination, other diseases of the CNS) and results of microglial reaction profiles were compared. Immunophenotypic characterization generally revealed relative high conformity in the microglial disease response among the different groups, however the functional response was shown to be more specific. Dogs with intracranial inflammation and dogs with demyelination showed an enhanced phagocytosis, whereas a significant up-regulation of ROS generation was found in dogs with demyelination due to CDV infection. This strongly suggests a specific response of microglia to infection with CDV in the settings of our study and underlines the pivotal role of microglial ROS generation in the pathogenesis of demyelinating diseases, such as canine distemper.     

Apoptosis in the cerebellum of dogs with distemper

Canine distemper virus (CDV) may induce multifocal demyelination in the central nervous system of infected dogs. The pathogenesis of this process is not clear. The present work identifies the presence of apoptotic cells in white and grey matter of dogs'cerebellum, naturally infected with CDV. Fifteen dogs with clinical signs of canine distemper that tested positive for CDV nucleoprotein were used. Brain specimens were processed and embedded in paraffin. Sections 5 microm thick were stained with hematoxylin-eosin and Shorr. Other sections were submitted to TUNEL reaction and to immunohistochemistry for CDV nucleoprotein detection. Acute and chronic demyelinated plaques were observed in the white matter, while apoptosis occurred particularly in the granular layer of grey matter. Apoptosis seems to play an important role in the pathogenesis of canine distemper demyelination.     

犬实验感染CDV的病理学研究

对实验感染犬瘟热病毒的病犬进行了系统的病理学观察,并用酶标ＳＰＡ法对病犬脏器组织中ＣＤＶ抗原进行了定位检查。结果表明,淋巴系统各器官组织是ＣＤＶ急性感染早期首先侵犯的靶器官。脏器组织的病理改变与ＣＤＶ抗原检出呈正相关。脏器组织中包涵体的检出与形态结构具有一定的特征性和示病意义,但采用免疫组化方法检查ＣＤＶ抗原,更具优越性。作者认为,ＣＤＶ９３０３９株和ＣＤＶ９３０４１株是致病力很强的泛嗜性ＣＤＶ。     

Phenotypical characterization of T and B cell areas in lymphoid tissues of dogs with spontaneous distemper

CD3, CD4, CD5, and CD8 antigen expression of T cells and IgG expression of B cells and canine distemper virus (CDV) antigen distribution were immunohistochemically examined in lymphoid tissues (lymph node, spleen, thymus, and tonsil) of control dogs and animals with spontaneous canine distemper. In addition, CNS tissue of all animals was studied for neuropathological changes and CDV antigen distribution. Based on the degree of depletion distemper dogs were classified into two groups. Group I represented animals with moderate to marked lymphoid depletion, while group II dogs displayed mild or no depletion. CDV antigen was mainly found in lymphocytes and macrophages of group I dogs, whereas CDV expression was most prominent in dendritic cells of group II animals. In group I dogs, a marked loss of CD3, CD4, CD5, CD8, and IgG expression was noticed, hereby loss of CD4+ cells was more prominent than depletion of CD8+ cells. In the lymphoid tissues of group II animals, a significant increase in the number of T and B cells was observed compared to group I dogs. The number of CD3+, CD4+, and CD8+ cells in group II dogs was similar to the findings in controls, however, CD5 and IgG expression was mildly reduced in T and B cell areas, respectively. Additionally, in groups I and II dogs, CD3+ and CD5- T cells were detected in T cell areas. Whether this cell population represents a cell type with autoimmune reactive potential remains to be determined. Surprisingly in group II animals, viral antigen was found predominantly in dendritic cells indicating a change in the cell tropism of CDV during chronic infection and a possible mechanism of viral persistence. The two patterns of lymphoid depletions correlated to two different types of canine distemper encephalitis (CDE). Group I dogs displayed acute non-inflammatory CDE, whereas group II dogs suffered from chronic inflammatory demyelinating CDE, indicating a pathogenic relationship between lymphocytic depletion and inflammatory brain lesions in distemper.