160 likes | 394 Views
Chapter 23. Arbovirus & Hemorrhagic Fever Virus. 虫媒病毒和出血热病毒. Arbovirus. 一群节肢动物媒介病毒 p302 表. Arbovirus of prevalence in China ---classified as Flavivirus. 主要有流行性乙型脑炎病毒、登革病毒和森林脑炎病毒. Common characteristics.
E N D
Chapter 23 Arbovirus & Hemorrhagic Fever Virus 虫媒病毒和出血热病毒
Arbovirus 一群节肢动物媒介病毒 p302表 • Arbovirus of prevalence in China ---classified as Flavivirus 主要有流行性乙型脑炎病毒、登革病毒和森林脑炎病毒 • Common characteristics Small spherical particle(40-70nm), +ssRNA, icosahedral nucleocapsid, envelope and spike Feature of diseases caused by Arbovirus •arthropod----both vector and reservoir hosts of virus•transmitted by bite of arthropod•obvious season and district•clinical manifestations(发热、脑炎、出血热) 节肢动物既是传播 媒介又是储存宿主
Encephalitis B Virus 乙型脑炎病毒 •also called Japanese encephalitis virus(JEV) •the most common cause of epidemic encephalitis
1. Biological Properties Typical flavivirus both in structure and in shape Structural protein:C,M and E protein(hemagglutinin) +ss-RNA 能凝集雏鸡、鸽和鹅的红细胞(PH6.0) (球形、单正链RNA 、 20面体对称的包膜病毒) Cultivation •suckling mice • embryo-eggs • cell culture(C6/36 cell) Antigenicity (single and stable)
2.Pathogenicity and Immunity Natural cycles of JEV 蚊→动物→蚊 bite mosquitodomestic animal or birds domestic animal mosquito or birds (young pigs) (culex) ova (viremia) 病毒血症 bite bite human • vector of transmission and reservoir • source of infection • route of transmission ---三节吻库蚊 蠛蠓 ,蝙蝠 ---幼猪 • epidemic season and district
JEV-infection (neurotropic virus→infection of CNS) • Asymptomatic infection • Abortive infection • Cause epidemic encephalitis B (0.1%) Immunity (IgM→IgG) ---long-lasting immunity
3.Laboratory Diagnosis Isolation of virus(cell culture)Serological diagnosis ---detection of specific IgM byantibody cupture-ELISA(ACELISA) 急性期阳性率>90% 4. Prevention Cut off the route of transmission Artificial active immunity Vaccination of the young pigs (vector control) (inoculate live or killed vaccines)
Dengue virus 登革病毒 (pathogen of dengue fever)
1.Biological properties Shape and structure(similar to JEV) Cultivation 4 serotypes(各型间有交叉) (C6/36细胞培养,乳鼠接种) 2. Pathogenicity Natural cycle of virus • human(monkey)→mosquitoes→Human (monkey) • vector---- aedes • source of infection and reservoir of virus 5~10月3~10月 白纹伊蚊( 西太平洋区, 广东) 埃及伊蚊(东南亚, 海南) 患者和隐感者 (人和猴子)
Dengue virus -infection • route of transmisson • primary infection→dengue fever • reinfection→dengue hemorrhagic fever(DHF) or dengue shock syndrome (DSS) • pathogenesis of DHF/DSS:ADE(antibody-dependent enhancement) 3.Laboratory diagnosis Detection of specific IgM (ELISA) Isolation of virus Detection of viral RNA
自习 Forest encephalitis virus (森林脑炎病毒) ---森林脑炎病毒(又称苏联春夏型脑炎病毒),是森林脑炎的病原体,该病是蜱传播的自然疫源性疾病(也是人畜共患病)
Hemorrhagic Fever Virus • important pathogens of causing hemorrhagic fever (p306 Table 23-2) • Hemorrhagic feverof prevalence in China 1.hantavirus 2.Xin-jiang hemorrhagic fever virus 3.dengue virus
Ⅰ. Hantavirus 1. Biological properties G1 Shape and structure G2 •round or elliptic virus •envelope with HA 凝集鹅红细胞 PH6.0~6.4 Genome d=120 nm --- segmented -ssRNA (L,M and S) polymerase Cultivation G1,G2 N (Cell culture and susceptible animal) Epidemic serotype in China •Hantaan virus (汉滩病毒,姬鼠型)•Seoul virus (汉城病毒,褐家鼠型)
2.Pathogenicity and Immunity Epidemiology 黑线姬鼠 褐家鼠 大白鼠 秋冬季 春夏季 带毒的宿主鼠 (尿/粪/唾液) •source of infection •mode of transmission •mite •obvious season and district (多种途径) (螨, both vectors and reservoir) Clinical syndromes •hemorrhagic fever with renal syndrome (HFRS,肾综合征出血热) •Hantavirus pulmonary syndrome (HPS,汉坦病毒肺综合征) 流行性出血热(EHF) Immunity (long-lasting immunity)
3.Laboratory diagnosis and prophylaxis Laboratory diagnosis---isolation of virus, detection of viral Ag and specific IgM or of viral RNA Prophylaxis
Ⅱ.XinJiang Hemorrhagic Fever virus 2.Pathogenicity 1.Properties of XHFV (similar to hantavirus) Source of infection Route of transmission Cause XinJiang Hemorrhagic Fever 家畜和野生动物 (by bite of hard tick with viruses) 自然疫源性疾病 3.Immunity ---long-lasting immunity