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1、Respiratory Disease Swine Influenza Virus 呼吸系统疾病猪流感病毒,Bob Morrison DVM, MBA, PhD Marie Gramer, DVM Kurt Rossow DVM, PhD,Etiology 病原学,SIV used to be straightforward 猪流感过去被认为并不重要 SIV diagnostics and disease control has become more challenging after the introduction of new types 在新类型病毒被报道后，猪流感的诊断和控制变得更
2、富挑战性。 Type A Influenza virus belongs to the Orthomyxoviridae family. A型流感病毒属于整粘病毒科 Enveloped, RNA virus 有囊膜、RNA病毒 Lipid envelope 脂质囊膜 Helical nucleocapsid. 螺旋状的病毒粒子,Swine Influenza Virus Structure 猪流感病毒结构,Fields Virology, Fourth Edition,RNA gene segments,脂质双分子层,神经氨酸酶,血凝素,M2离子通道,M1基质蛋白,感染细胞蛋白,RNA基因片断
3、,核衣壳,转录酶复合体,2 structural proteins present on the virus.病毒表面存在的两种结构蛋白,Hemagglutinin (13 types) 血凝素（13种类型） responsible for the attachment of the virus to the host-cell and for fusion of the viral envelope to the host-cell membrane 负责病毒附着到宿主细胞和让病毒囊膜与宿主细胞膜融合 Antibodies to the hemagglutinin are responsib
4、le for preventing infection with an influenza virus containing the same hemagglutinin protein. 血凝素的抗体可以起到阻止包含有相同血凝素蛋白的流感病毒感染的作用。 Neuraminidase protein (9 types) 神经氨酸酶（9种类型） responsible for elution of virus from erythrocytes. It may play a role in the release of virus from infected cells. 负责病毒从红细胞上脱离
5、。它可能在病毒从感染细胞上释放过程中起重要作用 antibodies against the neuraminidase restrict the spread of virus from infected cells. 神经氨酸酶的抗体限制了病毒由感染细胞的扩散。,These 2 surface glycoproteins are the basis for naming subtypes 这两种表面糖蛋白是命名亚型的基础,Four main subtypes in swine 感染猪的四个主要亚型 Most common in US 在美国最常见的 H1N1, H3N2 Also 以及 H
6、1N2, H1N7,Viral Change/Evolution 病毒的改变/进化 H1N1 and H3N2,Emerged in 2000 出现于2000年 7 genes from the H3N2 viruses 7个基因来自H3N2病毒,Emerged in 2002 出现于2002年 Surface of the H1N1 viruses 表面蛋白来自H1N1病毒 Internal gene components derived from the H3N2 viruses. 内部基因组件源于H3N2病毒,Pathogenesis 发病机理,The virus is inhaled
7、and deposited on the surface of the lower respiratory tract. 病毒被吸入并沉积于下呼吸道表面。 Incubation period from 1 - 3 days. 潜伏期从1-3天不等。 Widespread interstitial pneumonia for up to 21 days after infection and hemorrhagic lymph nodes may be seen. 弥漫性间质性肺炎在感染后21天出现，也可能出现出血性淋巴结。 Uncomplicated infections have chang
8、es in the cranial ventral lung lobes. There is generally a sharp line of demarcation between normal and affected lung tissue. 单纯性感染时病变出现于肺的尖叶。一般在正常和病变肺组织间有明显的界线。 The involved areas are often purple and firm. Some interlobular edema may also be evident. 感染病变区域常呈紫色硬结。一些小叶间质水肿明显。 The airways are likely
9、 to be filled with blood-tinged fibrinous exudate. Often the bronchial and mediastinal lymph nodes are enlarged. 通气道可能充满淡红色纤维素性渗出物。支气管和纵隔淋巴结常常肿大。,Clinical signs 临床症状,Very fast spread and affects high prevalence - aerosol spread probably occurs 非常快速的传播和可能出现以高感染力气溶胶形式传播的情形 Dyspnea, loud, nonproductive
10、 cough (bark), 呼吸困难、大声的无痰干咳（吠咳） Nasal and eye discharge, 鼻和眼有分泌物流出 High fevers (42.0 C) with lethargy and anorexia. 伴有高热（ 42.0 C ）的嗜睡和食欲不振 Most pigs recover spontaneously and quickly, 大部分猪可以自然快速痊愈， Often complicated by secondary infections 病情常因继发感染而变得复杂,Lesions 病变,Interstitial edema; wet heavy Lung
11、肺脏间质水肿；湿润，重量增加,Diagnosis 诊断,clinical signs with lung lesions, 临床症状及肺部病变 histopathological confirmation of lesions, 通过组织病理学确认的病变 paired sera, and （取）成对血清（样品）， antigen detection 抗原检定,Histopathology Necrotizing bronchiolitis. Airways filled with exudate. Widespread alveolar atelectasis, interstitial pn
12、eumonia and emphysema. Peribronchial and perivascular cellular infiltration. 组织病理学坏死性细支气管炎。通气道充满渗出物。广泛的肺泡性肺不张、间质性肺炎和间质水肿。支气管周围和血管周围细胞浸润。,Severe necrotizing bronchiolitis in the lung of a pig with swine influenza infection 猪流感感染猪肺部严重的坏死性细支气管炎,Necrotizing bronchiolitis associated with antigen (brown s
13、taining). 坏死性细支气管炎相关抗原（棕色染色部位）,Diagnosis 诊断,Virus shedding is early and of relatively short duration 病毒扩散出现在疾病早期且其扩散持续的时间相对较短 shedding is highest in the first few days of infection and is associated with fever 病毒扩散的高峰出现在感染的头几天而且与发热相关 Pigs may develop a second febrile episode after the influenza infe
14、ction due to secondary infections 猪在感染流感后由于继发感染可能出现第二发热期。 Lung lesions may take 4 weeks to resolve 肺部病变可以持续4周才结束,Samples for virus detection 病毒检验的样品采集,Samples for collection 样品的收集 Nasal swabs sample many pigs 鼻拭子在多头猪身上取样 Lung early 肺病变早期 Lung lavage acceptable sample, if the lavage is positive 肺部灌洗物
15、如灌洗物是阳性的，灌洗物是可接受的样品 Send packed with plenty of refrigerant 样品和大量冷却剂一同打包邮寄,Virus detection techniques 病毒检验技术,PCR sensitive, specific, rapid, sample can also be used for subtyping or sequencing 聚合酶链式反应敏感、特异性、快速，样品可被用于亚型确定或测序 Virus isolation sensitive ,specific, sample can be used for subtyping or sequ
16、encing 病毒分离敏感、特异性、快速，样品可被用于亚型确定或测序 Immunohistochemistry specific, “dead end” results 免疫组织化学特异性、“终端”结果 DirectigenR Flu A test DirectigenR 的A型流感检测 Histopathology 组织病理学,Serology 血清学,HI test 血凝抑制实验 pigs seroconvert approximately 3 weeks post infection. Detection of antibody and the resultant titer may depend on the virus used in the test. 猪血清学变化出现在感染后约3周。检验抗体和产生抗体的滴度将依赖于在实验中使用的病毒。 SIV H1 Elisa test 猪流感H1酶联免疫吸附实验 picks up most but not all H
