兽医专业英语（扬州大学）lesson 19

LessonNineteenFoot-and-MouthDiseaseNewwordsandphrasesGeographicSerotypeDesignateMortalityMorbidityConvalescenceProtractedRinderpestHusbandrySequelaeLactationPermanentRetardedCompulsoryDemarcationHeterogeneityThresholdpragmaticInseminationSemenAerosolPharyngealEquivocalNeutralizeHomologousPicornavirusTextFoot-and-mouthdiseaseisstillamajorglobalanimalhealthproblem,butitsgeographicdistributionhasbeenshrinkinginrecentyearsascontrolandeliminationprogramshavebeenestablishedinmoreandmorecountries.Sevenserotypesoffoot-and-mouthdiseasevirushavebeenidentifiedbycross-protectionandserologictests,andtheyaredesignatedO,A,C,SAT1,SAT2,SAT3,andAsia1.

Atonetimeoranother,thesevirusesoccurredinmostpartsoftheworld,oftencausingextensiveepidemicsindomesticcattleandswine.Sheepandmanyspeciesofwildlifearealsosusceptible.Mortalityislowbutmorbidityishigh;convalescenceandvirussheddingfromaffectedanimalsmaybeprotractedanditisthesefeaturesthatmakefoot-and-mouthdiseasesoimportant,especiallywhenthevirusisintroducedintocountriespreviouslyfreeof（无…的）disease.Duringthe19thcentury,foot-and-mouthdiseasewaswidelyreportedinEurope,Asia,Africa,andSouthandNorthAmericaandoccurredononeoccasion

（有一次；曾经）inAustralia.From1880onward,thecontrolofrinderpest（牛瘟）andtheimprovedhusbandryinthelivestockindustriesinEuropefocusedattentiononfoot-and-mouthdisease.Itssequelaewerefoundtobemoreimportantthantheacuteillness.Indairyherds（奶牛群）,thefebrile(发热的)diseaseresultedinthelossofmilkproductionfortherestofthelactationperiod（泌乳期）.Mastitisoftenresultedinapermanentlossofmorethan25%ofmilkproductionandtheretardedgrowthofbeefcattle.Today,manycountrieshaveeithereliminatedfoot-and-mouthdiseasebycompulsory（强制性的）slaughterofinfectedanimalsorhavereduceditsincidencegreatlybyextensivevaccinationprograms.Historically,eachvirustypehasbeenfurthersubtypedonthebasisofquantitativedifferencesincross-protectionandserologictests.Antigenicvariationwithinatypeoccursasacontinuousprocessofantigenicdrift

withoutclear-cut（清晰的）demarcationsbetweensubtypes.Thisantigenicheterogeneityhasimportanteconomicimplicationsforvaccinedevelopmentandselection,asimmunityacquiredthroughinfectionoruseofcurrentvaccinesisstrictlytypespecificand,toalesserdegree,subtypespecific.Difficultyindefiningthethreshold

atwhichanewisolateshouldbegivensubtypestatus

hasalwaysbeenaproblemandcurrentattitudesreflectapragmatic(实用的)approach.Newstrainsarenowcomparedwiththeestablishedvaccinestrainsofcommercialproducers,therebyavoidingthecomplexityofclassifyingnewisolateswithinaneverincreasingcatalogueofsubtypes,

manyofwhichhavelittlerelevancetocurrentproblemsinthefield.Themainrouteofinfectioninruminants(反刍动物)isthroughtheinhalationofdroplets（飞沫）,butingestionofinfectedfood,inoculationwithcontaminatedvaccines,inseminationwithcontaminatedsemen,andcontactwithcontaminatedclothing,veterinaryinstruments,andsooncanallproduceinfection.Inanimalsinfectedviatherespiratorytract,initialviralreplicationoccursinthepharynx（咽）,followedbyviremiaspreadtoothertissuesandorgansbeforetheonsetofclinicaldisease.

inhalation[,inhə‘leiʃən]n.吸入；吸入药剂；inhale[in'heil]vt.吸入；猛吃猛喝vi.吸气Viraemia[vai‘ri:miə].病毒血症；viremia

[vai'ri:miə]n.〈美〉病毒血症

ruminant

['ru:minənt]adj.反刍动物的,沉思的；pharynx

['færiŋks]n.[解]咽insemination

[in,semi'neiʃən]n.授精,播种；semen

['si:mən,-men]n.精液instrument

[,instrumənt]n.器具,仪器乐器；傀儡；正式的文件,文书；Viralexcretioncommencesabout24hourspriortotheonsetofclinicaldiseaseandcontinuesforseveraldays.Aerosols（气溶胶）producedbyinfectedanimalscontainlargeamountsofvirus,particularlythoseproducedbyswine.Largeamountsofvirusarealsoexcretedinthemilk.Theexcretionofvirusinhightiterindroplets（飞沫）andinmilkhasepidemiologicsignificanceandisimportantforthecontrolofdisease.Foot-and-mouthdiseasevirusmaypersistinthepharynxofsomeanimalsforaprolongedperiodafterrecovery.Incattle,virusmaybedetectableforperiodsupto2yearsafterexposuretoinfection,insheepforabout6months.Viralpersistencedoesnotoccurinswine.Thiscarrierstatehasalsobeenobservedinwildanimals,particularlytheAfricanCapebuffalo（非洲水牛）,whichiscommonlyfoundtobeinfectedwithmorethanoneoftheSATvirustypeseveninareaswherefoot-and-mouthdiseasedoesnotoccurincattle（家牛）.Themechanismsbywhichthevirusproducesapersistentinfection（持续性感染）inruminantsareunknown.Thevirusispresentinthepharynxinaninfectiousform,for

ifpharyngealfluidsareinoculatedintosusceptibleanimalstheydevelopfoot-and-mouthdisease.Attemptstodemonstratethatcarriercattlecantransmitdiseasebyplacingthemincontactwithsusceptibleanimals

havegivenequivocal(可疑的)results,buttransmissionofvirusfrompersistentlyinfectedAfricanCapebuffalotocattlehasbeenobserved.Recoveryfromclinicalfoot-and-mouthdiseaseiscorrelatedwiththedevelopmentofantibody.TheearlyIgMantibodiesneutralizethehomologoustypeofvirusandmayalsobeeffectiveagainstheterologoustypes.Incontrast,theIgGproducedduringconvalescenceistypespecificand,tovaryingdegrees(从不同的角度来讲),subtypespecific.Littleinformationisavailableontheroleofcell-mediatedimmunityinrecoveryfromfoot-and-mouthdisease,butasinotherpicornavirusinfections,ithasbeenassumedtobeofminorimportance.homologous

[hɔ‘mɔləɡəs]adj.相应的,类似的,一致的,[生物]同源的；homogeneity[,hɔməudʒe'ni:əti]同种；同质；同次性]heterologous

[,hetə‘rɔləɡəs]adj.异素[种]的；异种[质]的,异要素的heterogeneity[,hetərəudʒi'ni:əti]n.异质性；不均匀性；多相性picornavirus

[pi,kɔ:nə‘vaiərəs].小核糖核酸病毒pico微小Tovaryingdegrees:

从不同的角度来讲Cattlethathaverecoveredfromfoot-and-mouthdiseaseareusuallyimmunetoinfectionwiththesamevirustypeforayearormore,butimmunityisnotconsideredlifelong（纵身的）.Recoveredanimals,however,canbeinfectedimmediatelywithoneoftheothertypesoffoot-and-mouthdiseasevirusanddevelopclinicaldisease.标题和关键词羊口蹄疫O型和亚洲1型二价灭活疫苗免疫后O型抗体水平的检测DetectionofTypeOAntibodyLevelsafterImmunizationwithFMDVTypeOandAsia1InactivatedVaccineinSheep关键词:羊;口蹄疫;灭活疫苗;免疫程序Keywords:sheep;foot-and-mouthdisease;inactivatedvaccine;immuneprocedure摘要:为了探讨口蹄疫O型和亚洲1型二价灭活苗免疫接种羊后产生的O型抗体效价,采用不同免疫剂量和不同免疫时间免疫接种羊,应用正向间接血凝试验(IHA),检测其抗体消长规律。Abstract:InordertounderstandthetypeOantibodytitersinsheepinoculatedwithFMDtypeOandAsia1inactivatedvaccine,theantibodydynamicswasstudiedbyusingIHAmethodafterwithdifferentdosesandindifferenttime.结果表明,羔羊母源抗体水平及维持时间与母羊抗体水平呈正相关,有效保护抗体能维持70d左右;首免每只1mL、2mL同时免疫的4组间免疫抗体水平经方差分析差异不显著,首免不能产生有效的保护抗体水平;Theresultsshowedthatlevelsandsustainingtimeoflambmaternalantibodywereproportionaltothoseoftheirparents,theefficientprotectivelevelsofantibodiescouldmaintain70days.Afterthefistvaccination,antibodytitersofsimultaneouslyimmunized4groupswiththedosesof1mLand2mLhadnosignificantdifferenceandcouldnotproduceefficientprotectivelevels.二免2mL、2.5mL不同时间免疫的4组,首免后15d与首免后28d进行二免产生的抗体经t检验差异极显著(P<0.01),首免后28d二免的不同剂量组经方差分析差异不显著,有效抗体能维持约170d,首免后15d二免的免疫抗体水平最低;Afterthesecondvaccination,antibodylevelsof4groupsimmunizedindifferenttimewiththedosesof2mLand2.5mLweredifferent.Theantibodylevelsimmunized28daysafterfirstimmunizationwassignificanthigherthanthatimmunized15daysafterfirstimmunization(P<0.01),andtheefficientprotectivelevelcouldmaintain170days.每只三免2mL、3mL的2个剂量组产生的有效抗体均能维持180d,两组抗体经t检验差异不显著(P>0.05)。Afterthethirdimmunization,thedosesof2mLand3mLin2groups,efficientprotectivelevelscouldmaintainhalfayearandtheantibodytitersof2groupswerenotsignificantlydifferent(P>0.05).AnimmuneprocedureforsheepagainstFMDwasrecommendedbasedontheantibodydynamics.

Abstract:InfluenzaAvirusescontinuetocausewidespreadmorbidityandmortality.Therei