英语高级视听说

1、1Unit8ChasingTheFluIfthisyearoftsunamis,earthquakesandhurricaneshastaughtusanything,itsthatworstcasescenariosdosometimeshappen.Nowwithwinteruponus,thelatestthingtoworryaboutistheavianflu-aparticularlydeadlybirdvirusthatisravagingthepoultryindustryinAsia,andhas,onrareoccasions,infectedhumans,killingh

2、alfofitsvictims.Fewerthan100peoplehavediedworldwide,yettheWorldHealthOrganizationcallsitthemostserioushealththreatfacingtheplanet,greaterthanAIDSortuberculosis.Becausehumanshavenoimmunitytothevirus,andtherearenoprovendrugsorvaccinestostopit,ithasthepotentialtocauseaninfluenzapandemicsimilartotheonet

3、hatkilled50millionpeoplein1918.Itmaynothappen,butbillionsofdollarsarebeingspenttosequenceitsgenes,trackitsmovement,andslowitsprogressinwhatmanypeoplebelievecouldbearaceagainsttime.60MinutessetoutforEuropeandAsiachasingtheflu.CorrespondentSteveKroftreports.ItscalledtheH5N1virus,aprimitivepieceofgenet

4、icmaterialsosmallitcanbarelybeseenunderthemostpowerfulmicroscopes.Likeallfluviruses,itisconstantlyevolvingandeverydayscientistsrecordthelatestchangesasitmovessilentlyaroundtheglobeinthebelliesofbirds.ThevirushasinfectedthewaterfowlnowmigratingtheflywaysoverSoutheastAsia.Thisisthefrontlineinthebattle

5、againstavianflu,wherethemostcaseshavebeenidentifiedandthemostpeoplehavedied.Ducksandgeesehavepasseditalongtodomesticpoultry,andhumanshavegottenitfromsickbirds.Sofar,theviruscantpasseasilyfromhumantohuman,butasingledeadlymutationcouldchangethatandtriggerthedeathsoftensofmillionsofpeople.Timeistheesse

6、nce,saysDr.MargaretChan,theWorldHealthOrganizationschiefofPandemicInfluenzainGeneva.Shecallsitawarningsignalfromnature.Forthefirsttimeinhistoryweareseeingapandemicunfoldinginfrontofoureyes,saysDr.Chan.NoonehasmoreexperiencewithH5N1thanDr.Chan.ShewasdirectorofhealthinHongKongwhenthefirstoutbreakoccur

7、redtherein1997.Thisisavirusthataffectsmostlybirdsandhaskilledfewerthan100people.WhydoesDr.Chanseeitassuchaserioushealththreat?Weareseeingveryworryingsigns,thegeographicalspreadofthisvirus,andithasextendedbeyondtheusualsortofpoultrysector.Itisinfectingcats.Itscausingdeathintigers,andsoonandsoforth.No

8、wwearegettingallthesesignals,andwearetrackingthechangesofthevirus,sheexplains.Ifyoulookatthediseaseitcausesinhumanbeing,itisverysevere,withaveryhighfatalityrate.Morethanabouthalfofthepeopleinfecteddie.Wehavenotseenanythingquitelikeit,saysDr.Chan.Andalso,thisviruscausesunprecedentedspreadintheanimals

9、ector.Andwehaveneverseenthisintheentirehistoryofmankind.Thebestmindsinhealth,scienceandveterinarymedicinehavebeenmobilizedtotryandstopthebirdflubeforeitcanbecomehighlycontagiousinhumans.Nearly200millionchickensexposedtothevirushavealreadybeendestroyed,yet,inthelastfewmonthstheH5N1virushasspreadfromA

10、siaintoEurope.EverymorningattheWorldHealthOrganizationsStrategicHealthOperationsCenter,scientistsandpublichealthofficialsgathertogooverthelatestinformationandmonitoreverysuspectedhumaninfection.Theycallitthemorningprayers.ThemaninchargeisDr.MikeRyan.2Mostofthesecasesrepresentasituationinwhichtheviru

11、shasbreachedabarrierbetweenanimalsandhumans.Andeverytimeitbreachesthatbarrierisapotentialopportunityforapandemictostart.Soeachandeveryoneofthosecasesisimportantandvitalforustounderstandwhatsgoingon,saysDr.Ryan.TherehavebeenseveralcasesinVietnamandThailand,wherethevirusseemstohavespreadfromhumantohum

12、an,butonlytoclosefamilymembersandcaregivers.Thenthetransmissionstopped.Whatwehaventseenissustainedefficienthumantohumantransmission.Wehavenotseenchainsofinfection.Andofthatweresure.Andthatswhatweneedtolookoutfor,saysDr.Ryan.Todoit,Ryanisbuildinganinternationalsurveillancesystemwithministriesofhealth

13、allovertheworldthathehopeswouldbeabletodetectthetriggerpointofapandemic,thefirstsignsthatthevirushasbecomecontagiousinhumans.TheplancallsformedicalSWATteamstobeflowntothesite,toquarantinethearea,andbeginadministeringmillionsofdosesofadrugcalledTamiflu,thestrongestantiviralsavailable.Wewonthavetime,p

14、ossibly,atthebeginningofapandemiceventogetlaboratoryconfirmation.Itmaytakedaystogetlaboratoryconfirmation,saysDr.Ryan.Wemayhavetomakethisjudgmentonthebasisoftheexistenceofaclusterthatsspreadingquickly.Andthatsignalwillbeverystrong.Youllseethediseaseextendveryquicklyfromtwotofourtoten.To20.To30,50,an

15、dbeyondnumberofAndwhenyoustarttoseethatminiexplosionofcases,weregoingtohaveavery,veryshorttimeinwhichtodosomethingaboutthat.Veryshort.Howlongdoscientistshave?Theinterventiontimewillbemeasuredfromdaystoweeks.Ithinknolongerthanamonthattheextreme,saysDr.Ryan.Dr.Ryansaysifanoutbreakisntstoppedorcontroll

16、edin30days,scientistsmaylosethebattle,andnobodyknowswhetherthatcanbedone.HowgoodisDr.Ryanssurveillancesystem?Myfearisthatthereareblindspots.Thatthereareblindspotsinoursurveillancesystematnationallevel.Andthatcreatesblindspotsglobally,heexplains.OneofthoseblindspotsisinCambodia,thepoorestoftheSouthea

17、stAsiancountrieswherethevirusismostactive.Migratorywaterfowlhavealreadyinfecteddomesticducksandchickens,amajorsourceofproteinformostthepeoplehere.Manyofthemliveinpovertywithnoaccesstohealthcare.Sofar,thevirushaskilledfourpeopleinCambodia,allofthemthoughttohavebeenexposedtothebloodordroppingsofinfect

18、edchickensandducks,whicharestillslaughteredandsoldinopenairmarketsalloverthecountry.Anddoctorshereareasscarceashensteeth.OneofthemisDr.LySovann,theCambodiangovernmentsdirectorofdiseasesurveillance-themaninchargeofstoppingtheavianfluhere.Dr.Sovannsaysthegovernmentispreparedfortheeventofanoutbreak,but

19、sayswearenotreallygoodprepareyet.Iftherearesignsthatthediseaseisspreadingamonghumans,Dr.SovannsjobistoreportthefirstoutbreakstoofficialsinGenevaandwaitforinternationalhelptoarrive.Butwhen60MinutesvisitedCambodialastmonth,Dr.Sovannsaidhehadfewerthan150dosesoftheantiviraldrugTamifluforanationof13milli

20、onpeople.Dr.Sovannsaysthereisonlyonedoseperprovince.Butweneedmore,hesays.Dr.Sovannandhissixmemberstaffworkoutofasmallroomonthethirdfloorofthehealthministry,3wherehekeepsanemergencysupplyofbiohazardsuitspiledinhisoffice.Thepowergoesoffeverynightat7p.m.Ifhescalledtoapandemicemergency,hellhavetotakeata

21、xi.Heissupposedtobeinchargeofthenationalreportingsystem,butthereisoneofficephonefortheentirestaff.Thenationalpandemichotlineishispersonalcellphone.Butwhenyoutraveloutsidethecity,yourealizeitmaynotmatter.InmostvillagestherearenotelephonestocallDr.Sovann.Andeveniftherewas,Dr.MeggeMiller,anAustralianwh

22、oistheWorldHealthOrganizationsepidemiologistinCambodia,saysthereslittleawarenessofavianfluonceyougetouttothecountryside.Inthevillages,peoplelivewiththeirchickensandducks.Theyaremembersofthefamily,saysDr.Miller.TherearelotsofthingsinCambodiathatkillpeople.Everyyear,thousandsdiefromTB,malaria,tetanusa

23、ndotherinfections.Birdfluisnotyetamajorconcern.Peopledontbelieveinavianinfluenza,saysDr.Miller.ShesaysitispossiblecasesofavianfluinCambodiamayhavegoneundetected.Itspossiblethatwehavemissedcases,becausewewontpickupeverysinglecaseoccurringsingly,Dr.Millersays.Askedifshethinksthesurveillancesystemisgoo

24、denoughtodetectwhenthevirusmakesthejump,Dr.Millersays,Werenotgoingtopickupthefirstcaseorthesecondcase.Idontthinkwellpickupthefirstjump.Werejustnotgoingto.Whatwerehopingtobeabletodo,andImfairlyconfidentweshouldpickthisup,ifwegetafamilycluster,itwillworrypeople.Andsotheyllgolookingforanswers.So,hopefu

25、lly,inthatlookingforanswers,theyllgettotherightpeopleandthealertwillbetriggered,shesays.Dr.Millersaysthequalityofhealthcareinmanyvillagesisprimitive.Thankfullyinthisvillage,itsnottoodifficulttogettoahealthcenter.Imean,whethersomeoneisthereisthebigissue.Andalsowhethertheyreawareofthesymptomsofbirdflu

26、,sheexplains.Theskilllevelforhealthcareworkersisrudimentaryatbest.LessthanhalftheprovinceshavereceivedtrainingsessionsintheWHOsplanforflusurveillance,responseandcontainment.Thatplan,saysDr.Miller,mightbeworkableinCambodia.Therearealotoflogisticalissuesaroundmobilizingalotofmedicineandalotofpeopleina

27、shortspaceoftime.ImeanwecouldgetthemedicinetoPhnomPenh,butthenhowdowegetthemedicinefromPhnomPenhairportouttotheprovince?Andoneofthethingsweneedtodowiththissortofcontainmentstrategyisputaringaroundthevillageandmakesurenoonegoesintothevillageandnoonegoesout.Whichisgoingtobethemostdifficultthingtocontr

28、ol,becausepeoplearejustusedtogoingeverywhere,shesays.Dr.MillersaystheCambodiangovernmentisnotyetfullypreparedtorespondtoanoutbreakofbirdflu.Butneitheristherestoftheworld.IfH5N1weretobecomehighlycontagiousinhumansthiswinteritcouldspreadtoeverycountryintheworldinamatterofmonths.Thereisnowaygovernments

29、,healthorganizations,andpharmaceuticalmanufacturerswouldbeabletoproducesufficientamountsofthestrongestantiviraldrugsorvaccinestocontainit.Rightnow,andwealladmitthat,rightnowifwehadanexplosionofanH5N1wewouldnotbepreparedforthat,saysDr.AnthonyFaucioftheNationalInstitutesofHealth.Heisthenationspointman

30、ontheavianflu.TheNIHisnowtestingavaccinemadefromthecurrentbirdvirus,butwhetheritwouldworkagainstsomefuturemutantstrainthatiscontagiousinhumansisanybodysguess.Thisvirushasbeenaroundsince1997andtherearepeoplewhosaythatithasntmadethejumpyet4tothepointwhereitcanaffecthumans.Isitnotgoingto?Itisconceivabl

31、ethatthisvirushasalreadyreacheditsdeadendandtheselittleblipsofinfectionsarejustthingsthataremanifestationsofwhereitwouldliketogo,butitsnevergoingtogetthere,saysDr.Fauci.Ontheotherhand,themorethisvirusisinfectingandkillingchickens,andthemorepeoplethatgetinfectedbyit,thatsgoingtogivethevirusagreaterch