医学微生物学课件

1、Medical MicrobiologyDepartment of Microbiology, HMU2021/9/101第37章 肝炎病毒Hepatitis viruses微生物学教研室 凌 虹第二篇 致病性细菌2021/9/102 教学大纲掌握内容肝炎病毒的种类 乙型肝炎病毒形态结构、致病性、预防原则熟悉内容丁型肝炎病毒结构特征及致病特点戊型肝炎病毒传播途径及致病特点2021/9/103问题肝炎病毒有哪些？甲型肝炎病毒的传播方式、致病特点和预防原则简述乙型肝炎病毒的生物学性状、抗原抗体组成及检出的意义、传播方式、致病特点及预防原则丙型肝炎病毒的生物学特点和致病特点丁型肝炎病毒（HDV）的概

2、念简述戊型肝炎病毒传播方式和致病特点2021/9/104肝炎病毒（Hepatitis virus）以侵害肝脏为主引起病毒性肝炎的病毒种类：甲型肝炎病毒（HAV）、乙型肝炎病毒（HBV）、丙型肝炎病毒（HCV）、丁型肝炎病毒（HDV）、戊型肝炎病毒（HEV）、GBV-C/HGV、TTV其他病毒黄热病毒、CMV、EBV、风疹病毒等 2021/9/105Viral Hepatitis - Historical PerspectivesA“Infectious”“Serum”Viral hepatitisEntericallytransmittedParenterallytransmittedF, G

3、, TTV? otherENANBBDC2021/9/106Hepatitis A virus1973年Feinstone应用免疫电镜技术从急性肝炎患者粪便发现生物学性状与肠道病毒一致1982年国际病毒命名委员会将它分类为小核糖核酸病毒科肠道病毒属72型2021/9/107Anti-HAV PrevalenceHighIntermediateLowVery LowGeographic Distribution of HAV infection2021/9/108生物学性状HAV为球形颗粒，直径2732nm，无包膜。基因组为线状单正链RNA2021/9/109由VP14四种多肽组成VP1是主要衣

4、壳蛋白和中和抗原，能中和所有HAV细胞培养：HAV可用猴肾、人胚肾细胞等进行增殖和传代，但不引起CPE易感动物有黑猩猩、南美洲猴、猕猴等接种后可出现急性肝炎抵抗力：较强对乙醚、酸、热（60oC）稳定。高压、紫外、煮沸等可灭活2021/9/1010流行病学传染源患者和隐性感染者传播方式：粪口途径污染食物、水源、海产品引起暴发或散发流行 隐性感染率高成人HAV抗体阳性率高达70%90%2021/9/1011致病性非溶细胞型病毒，不直接杀伤细胞病毒复制量与症状严重程度不一致，故认为免疫应答参与损伤过程病后期粪便可检出sIgA抗体无慢性病例典型的甲肝是自限过程，大约三个月2021/9/1012 甲型肝

5、炎血清学变化过程2021/9/1013Sources of HAV Infection 1983-93Percentage of CasesSource: CDC, Viral Hepatitis Surveillance ProgramYearPersonal contactDay care centerForeign travelOutbreakDrug use403020100198319841985198619871988198919901991199219932021/9/1014Concentration of HAV in Various Body Fluids Source:V

6、iral Hepatitis and Liver Disease 1984;9-22J Infect Dis 1989;160:887-890FecesSerumSalivaUrine1001021041061081010Infectious Doses per ml2021/9/1015Age-specific Incidence of Hepatitis A 1983-93Source: CDC, National Notifiable Diseases Surveillance SystemYearReported Cases (per 100,000)19831984198519861

7、9871988198919901991199219930510152025 5-14 years 15-24 years 25-39 years 0-4 years 40+ years 2021/9/1016EndemicityDiseaseRatePeak Ageof InfectionTransmission PatternsHighLow to HighEarly childhoodPerson to person;outbreaks uncommonModerateHighLate childhood/ young adultsPerson to person;food and wat

8、erborne outbreaksLowLowYoung adultsPerson to person;food and waterborne outbreaksVery lowVery lowAdultsTravelers; outbreaks uncommonGlobal Patterns of Hepatitis A Virus Transmission2021/9/1017诊断（Laboratory Diagnosis）Acute infection is diagnosed by the detection of HAV-IgM in serum by EIAPast Infecti

9、on i.e. immunity is determined by the detection of HAV-IgG by EIA 2021/9/1018防治原则加强食品卫生管理，水源减毒疫苗株H2株和L1株已投放市场基因工程疫苗也正在研究之中应急预防可用丙种球蛋白2021/9/1019Many cases occur in community-wide outbreaksno risk factor identified for most caseshighest attack rates in 5-14 year oldschildren serve as reservoir of inf

10、ectionPersons at increased risk of infectiontravelershomosexual meninjecting drug users Hepatitis A Vaccination StrategiesEpidemiologic Considerations2021/9/1020Pre-exposuretravelers to intermediate and high HAV-endemic regionsPost-exposure (within 14 days)Routinehousehold and other intimate contact

11、sSelected situationsinstitutions (e.g., day care centers)common source exposure (e.g., food prepared by infected food handler)Hepatitis A Prevention - Immune Globulin2021/9/1021GroupAgeNo.DosesEL.U.* (ml)Schedule(months)Children and adolescents2-18 years3360 (0.5)0, 1, 6-12Adults18 years21,440 (1.0)

12、0, 6-12DosesHAVRIX*ELISA unitsRecommended Doses & Schedules of HAV Vaccination2021/9/1022Hapatitis B Virus1963年Blumberg在多次输血的血友病患者中发现澳抗，1968年确与血清型肝炎高度相关，1970年Dane在电镜下看到具有传染性的42nm病毒颗粒HBV在亚洲广泛流行，在中国约10%人口携带该病毒，全球约3.5亿2021/9/10231983年将HBV及与其分子结构、生物学特性相似的土拨鼠肝炎病毒(woodchuck hepatitis virus,WHV)、地松鼠肝炎病毒(gr

13、ound squirrel hepatitis virus,GSHV)及鸭肝炎病毒(duck hepatits virus,DHV)归纳起来独立命名为嗜肝病毒科（Hepadnaviridae）2021/9/1024HBsAg Prevalence8% - High 2-7% - Intermediate 2% - LowGeographic Distribution of Chronic HBV Infection2021/9/1025形态与结构2021/9/1026电镜检查血清标本可见小球形颗粒（22nm）、管形颗粒（22nmx50700nm）、大球形颗粒（42nm）2021/9/1027完

14、整的HBV颗粒亦称Dane颗粒，颗粒直径为42nm具有双层衣壳结构。外壳相当于包膜，由脂质双层和乙肝表面抗原（HBsAg）、多聚人血清白蛋白受体（PHSA-r）和前S抗原（Pre-S）组成。内部有28nm的核心，表面相当于内衣壳，含有乙型肝炎核心抗原（HBcAg）和乙型肝炎e抗原（HBeAg）。内部有HBV的DNA和DNA多聚酶2021/9/1028HBV 基因组DNA是由3.2KB的长链 L（-）和短链 S（+）（约为L链的50%至85%长）组成的不完全双链环状DNA，长链载有病毒蛋白质的全部密码，有4个开放读码框架(ORF)，分别称为S、C、P和X区2021/9/10292021/9/10

15、30HBV复制周期2021/9/10312021/9/1032HBV Replication HBV2.4 KB3.5 KBProvirusRTReplicateNuclear2.1 KB2021/9/1033 抗原组成HBV表面抗原（HBsAg）是机体受HBV感染的标志226AA，由S基因编码HBsAg有1个共同抗原决定簇a和2组互相排斥的亚型抗原决定簇d/y和w/r4种亚型：adr、adw、ayr、 ayw我国内地和沿海各省汉族主要为adr型，欧美为adw 抗HBs能与HBV表面结合，使其失去感染性，具有保护作用2021/9/1034HBV核心抗原（HBcAg）在肝细胞核中才能检出分子量2

16、2KD，由C基因编码，病毒内衣壳蛋白一般方法在血中检测不到抗HBc无中和作用检出高效价抗HBc，特别是抗HBc IgM表示HBV再肝内处于增殖状态2021/9/1035HBVe抗原（HBeAg）由PreC和C基因共同编码，15KDHBcAg在细胞经蛋白酶降解形成HBV复制及血清有传染性的标志抗Hbe对HBV感染有一定保护作用2021/9/1036前S抗原（Pre-S Ag）前S2蛋白S + PreS2编码，226 + 55=281AA前S1蛋白S + PreS2 + PreS1编码，226 + 55 + 119 = 400AA与HBsAg、HBV DNA检出相同，都说明病毒在复制2021/9/

17、1037Pre-S2抗原和人肝细胞表面都具有PHSA受体，通过PHSAr搭桥，HBV病毒易吸附于肝细胞表面部分解释为什么HBV具有嗜肝细胞性抗前S1和抗前S2抗体具有中和HBV作用，有保护作用2021/9/1038易感动物和细胞培养：只有黑猩猩对HBV易感，体外细胞培养尚未成功2021/9/1039抵抗力：强对低温、干燥、UV、醚、氯仿、酚等均有抵抗性高压蒸汽灭菌、0.5%过氧乙酸、5%次氯酸钠、3%漂白粉液、0.2%新洁尔灭均可灭活病毒，但处理时间要稍长2021/9/1040Incubation period:Average 60-90 daysRange 45-180 daysClinic

18、al illness (jaundice):5 yrs, 10%5 yrs, 30%-50%Acute case-fatality rate:0.5%-1%Chronic infection:8%): 45% of global populationlifetime risk of infection 60%early childhood infections commonIntermediate (2%-7%): 43% of global populationlifetime risk of infection 20%-60%infections occur in all age grou

19、psLow (2%): 12% of global populationlifetime risk of infection 20%most infections occur in adult risk groupsGlobal Patterns of Chronic HBV Infection2021/9/1043 HighModerateLow/NTbloodsemenurineserumvaginal fluidfeceswound exudatessalivasweattearsbreastmilkConcentration of Hepatitis B Virus in Variou

20、s Body Fluids2021/9/1044 Modes of Transmission of HBVSexual sexual and homosexuals are particular at riskParenteral Intravenous drug abuse (IVDA), Health Workers are at increased riskPerinatalMothers who are HBeAg positive are much more likely to transmit to their offspring than those who are not Pe

21、rinatal transmission is the main means of transmission in high prevalence populations2021/9/1045传染源：急、慢性乙肝患者及无症状携带者传播途径：非胃肠道途径血液、血制品传播输血、丙种球蛋白医源性传播：注射（吸毒）、手术、采血、针刺、拨牙、内窥镜检查、纹身等接触传播：公共卫生洁具、剃刀、吸血昆虫母婴传播宫内感染相对少（10%）母亲HBeAg阳性婴儿感染机会大（90%）HBeAg阴性、抗HBe阳性婴儿感染机率小（10%15%）2021/9/1046* Includes sexual contact wi

22、th acute cases, carriers, and multiple partners. Source: CDC Sentinel Counties Study of Viral HepatitisHeterosexual* (41%)Homosexual Activity (9%)Household Contact (2%)Health Care Employment (1%)Other (1%)Unknown (31%)InjectingDrug Use(15%)Risk factors for Acute Hepatitis B1992-1993 USA2021/9/1047So

23、urce: CDC Viral Hepatitis Surveillance Program0-1415-1920-2930-3940+0510152025Rate of Reported Hepatitis B by Age Group USA 1990Age Group (years)Rate (/100,000)2021/9/1048ExposureInfectionDeath 1%FulminanthepatitisRecovery90% - 95% ImmuneAsymptomatic CarrierPersistent InfectionChromic hepatitisChron

24、ic active hepatitisCirrhosisHepatocellular carcinoma2021/9/1049致病机理尚未完全明了HBV不直接损害肝细胞，通过宿主的免疫应答引起肝细胞的损伤和破坏2021/9/1050细胞免疫损伤细胞免疫强弱与临床过程轻重与转归密切相关免疫力过强可出现重症肝炎，过低则是慢性肝炎体液免疫损伤：不十分重要先天性无丙种球蛋白血症患者乙肝仍表现为典型的肝炎病变抗原抗体复合物超敏反应，造成了肝外症状表现自身免疫损伤HBV感染后，肝细胞自身表面抗原肝特异性脂蛋白抗原（Liver specific protein, LSP）暴露2021/9/1051HBV与原

25、发性肝细胞癌乙肝患者原发性肝癌发生率比对照高原发性肝癌患者有HBV感染标志者比自然人群多HBV感染者比阴性者发生原发性肝癌的危险性高217倍WHV可诱导土拨鼠肝硬化及原发性肝癌新生土拨鼠感染WHV三年后100%发生肝癌未感染鼠则无一只发生肝癌肝癌细胞DNA整合有HBV-DNA2021/9/1052免疫性体液免疫HBV的中和抗体抗HBs抗Pre-S2细胞免疫CTL是清除细胞内病毒的主要机制细胞免疫处于较低水平则易转为慢性2021/9/1053微生物学检查法病毒核酸的检测斑点杂交法，PCR，极敏感的方法，临床常规对血清病毒DNA浓度可做动态监测HBV抗原、抗体的检测最敏感方法是RIA、ELISA检

26、测项目HBsAg和抗-HBsHBeAg和抗-Hbe抗-HBcIgM和抗HBc-IgG2021/9/1054SymptomsHBeAganti-HBeTotal anti-HBcIgM anti-HBcanti-HBsHBsAg0481216202428323652100Typical Serologic CourseWeeks after ExposureTitreAcute Hepatitis B Virus Infection with Recovery2021/9/1055IgM anti-HBcTotal anti-HBcHBsAgAcute(6 months)HBeAgChronic

27、(Years)anti-HBe0481216202428323652YearsWeeks after ExposureTitreProgression to Chronic Hepatitis B Virus InfectionTypical Serologic Course2021/9/1056HBsA：表示机体感染了HBV急性乙型肝炎潜伏期和急性期（70%）HBV所致的慢性肝病如慢性乙型肝炎、肝硬化和原发性肝炎无症状HBsAg携带者抗HBs机体曾感染过HBV，并获得对HBV的免疫力2021/9/1057HBcAg：常规方法难以检出，临床不做抗HBc抗HBc IgM出现于急性乙型肝炎急性期抗

28、HBc IgG阳性表示过去感染过HBV，少数也可能仍有HBV感染2021/9/1058HBeAg：体内HBV复制和血液传染性强急性乙肝HBeAg呈短暂阳性，如持续阳性提示转为慢性，预后不良孕妇HBeAg阳性，新生儿感染率高抗Hbe见于急性乙肝的恢复期，可持续较长时间机体获得一定免疫力2021/9/1059Pre-S1、Pre-S2和PHSA受体HBV新感染的标志，检出表示HBV正在复制抗Pre-S1、抗Pre-S2中和病毒出现于急性乙肝恢复早期消失较快2021/9/1060Examples of Serology Test2021/9/1061预防原则要采取切断传播途径为主的综合性措施自动免疫

29、：HBsAg疫苗（血源或重组）被动免疫：乙肝免疫球蛋白(HBIg)。接种者:医务人员或实验室工作人员HBsAg、HBeAg阳性母亲的新生儿发现已误用HBsAg阳性的血液或血制品者与HBsAg、HBeAg阳性者有密切性接触者2021/9/1062Elimination of HBV TransmissionPrevent perinatal HBV transmissionRoutine vaccination all infantschildren in high-risk groupsadolescentsall unvaccinated children at 11-12 yearsadu

30、lts in high-risk groups2021/9/1063VaccinelicensedHBsAg screeningof pregnant women recommendedInfantimmunizationrecommendedAdolescent immunization recommendedDecline among homosexual men & HCWsDecline among injectingdrug users80706050403020100787980818283848586878889909192939495YearCases per 100,000

31、PopulationEstimated Incidence of Acute Hepatitis B, USA 1978-1995 2021/9/1064Hepatitis C virus1978年WHO将非甲非乙型肝炎病毒按传播途径分为肠道传播的非甲非乙型病毒和肠道外传播的非甲非乙型肝炎病毒1989年进一步将前者命名为戊型肝炎病毒（HEV），将后者命名为丙型肝炎病毒（HCV）目前拟将HCV和庚型肝炎病毒（HGV）列入黄病毒科（Flavivurus）Hepacivirus属2021/9/10652021/9/1066生物学性状HCV属于黄病毒科，电镜照片不清晰，似球形，直径5565 nm，有脂

32、蛋白包膜，包膜上有短突起。核酸为+ssRNA，9.4Kb2021/9/1067由于不能培养，故尚不能进行血清分型据基因序列同源性，分为I VI六个基因型。中国和亚洲流行多型，欧美为I 型细胞培养未成功黑猩猩是唯一易感动物2021/9/1068 hypervariableregioncapsidenvelopeproteinprotease/helicaseRNA polymerasec225coreE1E2NS2NS333cNS4c-100NS53Hepatitis C Virus Genome2021/9/1069 HCV基因结构2021/9/1070 Hepatitis C - Clini

33、cal Features潜伏期 平均6-7周（2-26周）急性表现（黄疸） 轻微(20%)急性期死亡率 低慢性感染率75%-85%慢性肝炎70% 肝硬化10%-20%慢性肝脏疾病导致死亡1%-5%2021/9/1071Chronic Hepatitis C InfectionThe spectrum of chronic hepatitis C infection is essentially the same as chronic hepatitis B infectionAll the manifestations of chronic hepatitis B infection may

34、be seen, albeit with a lower frequency i.e. chronic persistent hepatitis, chronic active hepatitis, cirrhosis, and hepatocellular carcinoma2021/9/1072病理HCV不直接杀伤细胞病理免疫和细胞凋亡是造成伤害原因2021/9/1073Transmission of HCVPercutaneous Intravenous drug abuseTransfusion, transplant Therapeutic (contaminated equipme

35、nt, unsafe injection practices)PermucosalPerinatalSexual2021/9/1074Sources of Infection forPersons with Hepatitis CSexual 15%Other* 5%Unknown 10%Injecting drug use 60%Transfusion 10%(before screening)*Nosocomial; Health-care work; PerinatalSource: Centers for Disease Control and Prevention2021/9/107

36、5Source: Sentinel Counties, CDCHCV Prevalence by Selected Groups, USAHemophiliaInjecting drug usersSurgeons, PSWsHemodialysis Average Percent Anti-HCV PositiveGen population adultsMilitary personnelSTD clientsPregnant women2021/9/1076Prevalence of HCV Infection by Age & Gender, 1988-1994 USAMalesFem

37、alesSource: CDC, NHANES IIITotal2021/9/1077Perinatal Transmission of HCVTransmission only from women HCV-RNA positive at deliveryAverage rate of infection 6%Higher (17%) if woman co-infected with HIVNo association withDelivery methodBreastfeedingInfected infants do wellSevere hepatitis is rare2021/9

38、/1078Household Transmission of HCVRare but not absentCould occur through percutaneous/mucosal exposures to bloodTheoretically through sharing of contaminated personal articles (razors, toothbrushes)Contaminated equipment used for home therapiesInjections*Folk remedies79*Reported in U.S.Serologic Pat

39、tern of Acute HCV Infection with RecoverySymptoms +/-Time after ExposureTiteranti-HCVALTNormal01234561234YearsMonthsHCV RNA 2021/9/1080Serologic Pattern of Chronic HCV Infection with Progression InfectionSymptoms +/-Time after ExposureTiteranti-HCVALTNormal01234561234YearsMonthsHCV RNA 2021/9/1081La

40、boratory DiagnosisHCV antibody - generally used to diagnose hepatitis C infection. Not useful in the acute phase as it takes at least 4 weeks after infection before antibody appears.HCV-RNA - various techniques are available e.g. PCR and branched DNA. May be used to diagnose HCV infection in the acu

41、te phase. However, its main use is in monitoring the response to antiviral therapy.HCV-antigen - an EIA for HCV antigen is available. It is used in the same capacity as HCV-RNA tests but is much easier to carry out.2021/9/1082HCV Infection Testing Algorithmfor Diagnosis of Asymptomatic PersonsEIA fo

42、r Anti-HCVNegative (non-reactive)STOPPositive (repeat reactive)ORRIBA for Anti-HCVRT-PCR for HCV RNANegativeSTOPAdditional Laboratory Evaluation (e.g. PCR, ALT)NegativePositiveIndeterminateMedical EvaluationPositiveNegative PCR, Normal ALTPositive PCR, Abnormal ALTSource: MMWR 1998;47 (No. RR 19)202

43、1/9/1083Routine HCV Testing Not Recommended (Unless Risk Factor Identified) Health-care, emergency medical, and public safety workers Pregnant women Household (non-sexual) contacts of HCV-positive persons2021/9/1084Screening of blood, organ, tissue donorsHigh-risk behavior modificationBlood and body

44、 fluid precautions Prevention of Hepatitis C2021/9/1085Estimated Incidence of Acute HCV Infection, 1960-1999 USADecline intransfusion recipientsDecline in injection drug usersSource: Hepatology 2000;31:777-82 Hepatology 1997;26:62S-65S 2021/9/1086Posttransfusion Hepatitis C All volunteer donorsHBsAg

45、Donor Screening for HIV Risk FactorsAnti-HIVALT/Anti-HBcAnti-HCVImproved HCV TestsAdapted from HJ Alter and Tobler and Busch, Clin Chem 19972021/9/1087TreatmentInterferon - may be considered for patients with chronic active hepatitis. The response rate is around 50% but 50% of responders will relaps

46、e upon withdrawal of treatment.Ribavirin - there is less experience with ribavirin than interferon. However, recent studies suggest that a combination of interferon and ribavirin is more effective than interferon alone.2021/9/1088Hepatitis D virus肝炎病毒（Hepatitis virus）从HBV感染者中发现的2021/9/1089HDV Preval

47、enceHighIntermediateLowVery LowNo DataTaiwanPacific IslandsGeographic Distribution of HDV Infection2021/9/1090生物学性状3537nm，球形颗粒环状单股负链RNA和HDAg（即抗原） 1.7Kb表面为HBV包膜蛋白（HBsAg）2021/9/1091HBsAgRNAd antigen2021/9/1092HDV为缺陷病毒不能独立进行复制，必须在HBV或其它嗜肝DNA病毒辅助才能增殖敏感动物黑猩猩，土拨鼠和北京鸭等2021/9/1093Hepatitis D - Clinical Feat

48、uresCoinfectionsevere acute diseaselow risk of chronic infectionSuperinfectionusually develop chronic HDV infectionhigh risk of severe chronic liver diseasemay present as an acute hepatitis2021/9/1094 HDV TransmissionPercutanous exposuresinjecting drug usePermucosal exposuressex contact2021/9/1095免疫

49、性抗HDV 不能清除病毒，为诊断指标HDV IgM和IgG持续存在，提示为HDV慢性感染2021/9/1096Time after ExposureTiteranti-HBsSymptomsALT ElevatedTotal anti-HDVIgM anti-HDVHDV RNAHBsAgSerological Course of Acute HDV infection2021/9/1097Time after ExposureTiterJaundiceSymptomsALTTotal anti-HDVIgM anti-HDVHDV RNAHBsAgSerological Course of

50、HDV superinfection2021/9/1098微生物学检查法血清学方法ELISA检查HDAg或抗HDVHDAg在急性期可阳性，检出率低慢性感染检不到核酸分子杂交法2021/9/1099HBV-HDV CoinfectionPre or postexposure prophylaxis to prevent HBV infection.HBV-HDV SuperinfectionEducation to reduce risk behaviors among persons with chronic HBV infection. Hepatitis D - Prevention2021/9/10100Hepatitis E virus，HEV戊型肝炎病毒经肠道传播的非甲非乙型肝炎病毒疾病：戊型肝炎2021/9/10101Geographic Distribution of Hepatitis E2021/9/10102生物学性状2021/9/10103