医学课件肠道病毒与轮状病毒

Poliovirus Nervoussystem Polioisavirusthatinfectsthenervoussystemofhumans only Paralysis ItcancausetemporaryorpermanentparalysisordeathVaccine ThereisavaccineforpolioEradicate TheWorldHealthOrganizationplanstoeradicatepoliointhenextdecadeContinue Poliooutbreakscontinuetooccurinareasinwhichmanyarenotvaccinated SincevaccinehasbecomewidespreadintheUnitedStates casesofpolioarerare However polioremainsaprobleminmanypartsoftheworld 肠道病毒 Poliovirusinfectshumancellsbybindingtoanimmunoglobulin likereceptor CD155 alsoknownasthepoliovirusreceptor PVR onthecellsurfacePoliovirusisapositivestrandedRNAvirus ThusthegenomeenclosedwithintheviralparticlecanbeusedasmessengerRNAandimmediatelytranslatedbythehostcell Poliovirususestwokeymechanismstoevadetheimmunesystem First itiscapableofsurvivingthehighlyacidicconditionsofthegastrointestinaltract allowingthevirustoinfectthehostandspreadthroughoutthebodyviathelymphaticsystem Second becauseitcanreplicateveryquickly thevirusoverwhelmsthehostorgansbeforeanimmuneresponsecanbemounted 5 Immunesystemavoidance 学习要求 poliovirus 3 Dimageofpoliovirus Fordecades nooneknewwhatpolioviruslookedlike sincevirusescannotbeseenunderamicroscope In1985 ateamledbyJamesHogleofHarvardMedicalSchoolobtainedhigh resolution 3Dimagesofpoliovirus andtoday thenewlyformedChildren sHospitalBoston HarvardMedicalSchoolstructuralbiologyunitisheirtotheEnderstradition LedbyStephenHarrison thisgroupisusingavarietyofsophisticatedtoolslikeX raycrystallographyandmolecularelectronmicroscopytoobtaindetailed dynamic 3Dviews accuratedowntotheatom ofhowvirusesmove transferinformationandreconfigurethemselvestoattacktheirvictims Theseimagesaresheddinglightonmanyoftoday sviralscourges suchasHIV dengueandrotavirus andprovidingnewleadsfortreatmentandvaccinedevelopment Poliovirus AnancientEgyptianstele portrayingaprincewithawitheredleg probablypolio WHO GPEI ResearchersGlimpsePolioVirusasitEntersHostCellContact Theimageontheleftshowsanakedpoliovirus Thepoliovirusontherightisstuddedwith60twig likestructures thereceptors Seeforamoment Smallthinstemonatree 3 Dstructures Thepolioviruslivesinthethroatandintestinaltractofinfectedpersons Thevirusentersthebodythroughthemouth usuallyfromhandscontaminatedwiththestoolofaninfectedperson Objects suchaseatingutensils canalsospreadthevirus Foodandwaterarenotthoughttoplayamajorroleinthespreadofpolio WHO Poliocaseshavedecreasedby99 8 since1988 fromanestimated350000casesto483in2001 Thereductionistheresultoftheglobalefforttoeradicatethedisease Areaswithhigh intensitytransmission Together thesecountriesaccountedformorethan85 ofthenewpoliocaseloadin2001 Theyarecharacterizedbyhavingareaswithlargepopulationsandlowroutineimmunizationcoverage sub optimalsanitationandrelativelywidegeographicaldistributionofthewildpoliovirus Thesecountriesare IndiaPakistan AfghanistanNigeria Niger 病毒抵抗力 在污水和粪便中可活数月食品中可保存数周不易被胃酸或胆汁灭活对氧化剂敏感56 C30min被灭活 致病性 传染源 病人或无症状携带者传染方式 粪 口途径致病机理 二 致病性 病毒 咽部 肠壁淋巴组织 入血流 第1次病毒血症 入全身淋巴组织 再次入血流 病毒入脊髓前角运动神经细胞 脊髓型 延髓和脑干 延髓型大脑运动皮质区 脑炎型 第2次病毒血症 感染类型 人群中绝大多数为隐性感染或轻型感染显性感染引起麻痹者仅为显性感染的0 1 1 顿挫感染 免疫性 SIgA 清除肠道内病毒 阻止病毒入血IgM IgG 阻断血流中病毒向中枢神经系统扩散感染后获得对同型病毒较牢固的免疫力 Symptoms Noteveryonewillexperienceallthesymptoms whichvaryaccordingtothetypeofpolioonehas Inmildpoliothesymptomsare HeadacheNausea vomitingGeneraldiscomfortorslightfeverforuptothreedays Innon paralyticpolio thesymptomsaresimilartomildpoliowiththeadditionof ModeratefeverStiffneckandbackFatigueMusclepain Individualswithparalyticpoliowillexperience TremorsMuscleweaknessFeverStiffnessConstipationMusclepainandspasmsDifficultyswallowing 预防 口服脊髓灰质炎减毒活疫苗糖丸 1957年发明 OralvaccinationwithlivevaccineVaccinationprogramshaveeradicateditfromtheWesternworldandpromisetoeliminateitglobally DrAlberSabin 疫苗使用的效果 Scientistshavebuiltthevirusthatcausespoliofromscratchinthelab usingnothingmorethangeneticsequenceinformationfrompublicdatabasesandreadilyavailabletechnology Thefactprovesthatevenifallthepoliovirusintheworldweredestroyed itwouldbeeasilypossibletoresurrectthecripplingdisease saysAnikoPaulattheStateUniversityofNewYorkatStonyBrook oneoftheresearchersconductingthestudy 新进展Date Thu 11Jul2002 Bringbackintouse Journalreference Science DOI 10 1126 science 1072266 Theresulthasmajorimplicationsforvaccinationprogramsthathavenearlyridtheworldofpolio Ithinkitmeansyou reprobablynotgoingtobeabletostopvaccinatingpeopleevenafteryoueradicatethevirus saysDianeGriffinoftheJohnsHopkinsBloombergSchoolofPublicHealth Paulbelievesthesynthesismethodcouldbeappliedtootherviraldiseases Wefeelthiscouldbeusedforebola smallpox justaboutanything shesays Thisraisestheworryingpossibilitythatbioterroristscoulduseasimilarapproachtocreatedevastatingdiseaseswithouthavingtogainaccesstoprotectviralstocks paralysis electronmicroscopyandX raycrystallography Summaryofpoliovirus vaccinationprogramshaveeradicateditfromtheWesternworldandpromisetoeliminateitglobally Surprisinglylittleisknownabouthowpoliovirusentersthecellsoftheintestines letalonehowitmakesitswaytothenervoussystemwhereitcandamagemotorneuronsandcauseparalysis 轮状病毒 形态 核心为dsR