unit-8chasing-the-flu

Unit8ChasingTheFluIfthisyearoftsunamis,earthquakesandhurricaneshastaughtusanything,it'sthatworstcasescenariosdosometimeshappen.Nowwithwinteruponus,thelatestthingtoworryaboutistheavianflu--aparticularlydeadlybirdvirusthatisravagingthepoultryindustryinAsia,andhas,onrareoccasions,infectedhumans,killinghalfofitsvictims.Fewerthan100peoplehavediedworldwide,yettheWorldHealthOrganizationcallsitthemostserioushealththreatfacingtheplanet,greaterthanAIDSortuberculosis.Becausehumanshavenoimmunitytothevirus,andtherearenoprovendrugsorvaccinestostopit,ithasthepotentialtocauseaninfluenzapandemicsimilartotheonethatkilled50millionpeoplein1918.Itmaynothappen,butbillionsofdollarsarebeingspenttosequenceitsgenes,trackitsmovement,andslowitsprogressinwhatmanypeoplebelievecouldbearaceagainsttime.60MinutessetoutforEuropeandAsiachasingtheflu.CorrespondentSteveKroftreports.It'scalledtheH5N1virus,aprimitivepieceofgeneticmaterialsosmallitcanbarelybeseenunderthemostpowerfulmicroscopes.Likeallfluviruses,itisconstantlyevolvingandeverydayscientistsrecordthelatestchangesasitmovessilentlyaroundtheglobeinthebelliesofbirds.ThevirushasinfectedthewaterfowlnowmigratingtheflywaysoverSoutheastAsia.Thisisthefrontlineinthebattleagainstavianflu,wherethemostcaseshavebeenidentifiedandthemostpeoplehavedied.Ducksandgeesehavepasseditalongtodomesticpoultry,andhumanshavegottenitfromsickbirds.Sofar,theviruscan'tpasseasilyfromhumantohuman,butasingledeadlymutationcouldchangethatandtriggerthedeathsoftensofmillionsofpeople.Timeistheessence,saysDr.MargaretChan,theWorldHealthOrganization'schiefofPandemicInfluenzainGeneva.Shecallsitawarningsignalfromnature.Forthefirsttimeinhistoryweareseeingapandemicunfoldinginfrontofoureyes,saysDr.Chan.NoonehasmoreexperiencewithH5N1thanDr.Chan.ShewasdirectorofhealthinHongKongwhenthefirstoutbreakoccurredtherein1997.Thisisavirusthataffectsmostlybirdsandhaskilledfewerthan100people.WhydoesDr.Chanseeitassuchaserioushealththreat?Weareseeingveryworryingsigns,thegeographicalspreadofthisvirus,andithasextendedbeyondtheusualsortofpoultrysector.Itisinfectingcats.It'scausingdeathintigers,andsoonandsoforth.Nowwearegettingallthesesignals,andwearetrackingthechangesofthevirus,sheexplains.Ifyoulookatthediseaseitcausesinhumanbeing,[it]isverysevere,withaveryhighfatalityrate.Morethanabouthalfofthepeopleinfecteddie.Wehavenotseenanythingquitelikeit,saysDr.Chan.Andalso,thisviruscausesunprecedentedspreadintheanimalsector.Andwehaveneverseenthisintheentirehistoryofmankind.Thebestmindsinhealth,scienceandveterinarymedicinehavebeenmobilizedtotryandstopthebirdflubeforeitcanbecomehighlycontagiousinhumans.Nearly200millionchickensexposedtothevirushavealreadybeendestroyed,yet,inthelastfewmonthstheH5N1virushasspreadfromAsiaintoEurope.EverymorningattheWorldHealthOrganization'sStrategicHealthOperationsCenter,scientistsandpublichealthofficialsgathertogooverthelatestinformationandmonitoreverysuspectedhumaninfection.Theycallitthemorningprayers.ThemaninchargeisDr.MikeRyan.Mostofthesecasesrepresentasituationinwhichthevirushasbreachedabarrierbetweenanimalsandhumans.Andeverytimeitbreachesthatbarrierisapotentialopportunityforapandemictostart.Soeachandeveryoneofthosecasesisimportantandvitalforustounderstandwhat'sgoingon,saysDr.Ryan.TherehavebeenseveralcasesinVietnamandThailand,wherethevirusseemstohavespreadfromhumantohuman,butonlytoclosefamilymembersandcaregivers.Thenthetransmissionstopped.Whatwehaven'tseenissustainedefficienthumantohumantransmission.Wehavenotseenchainsofinfection.Andofthatwe'resure.Andthat'swhatweneedtolookoutfor,saysDr.Ryan.Todoit,Ryanisbuildinganinternationalsurveillancesystemwithministriesofhealthallovertheworldthathehopeswouldbeabletodetectthetriggerpointofapandemic,thefirstsignsthatthevirushasbecomecontagiousinhumans.TheplancallsformedicalSWATteamstobeflowntothesite,toquarantinethearea,andbeginadministeringmillionsofdosesofadrugcalledTamiflu,thestrongestantiviralsavailable.Wewon'thavetime,possibly,atthebeginningofapandemiceventogetlaboratoryconfirmation.Itmaytakedaystogetlaboratoryconfirmation,saysDr.Ryan.Wemayhavetomakethisjudgmentonthebasisoftheexistenceofaclusterthat'sspreadingquickly.Andthatsignalwillbeverystrong.You'llseethediseaseextendveryquicklyfromtwotofourtoten.To20.To30,50,andbeyondnumberof…Andwhenyoustarttoseethatminiexplosionofcases,we'regoingtohaveavery,veryshorttimeinwhichtodosomethingaboutthat.Veryshort.Howlongdoscientistshave?Theinterventiontimewillbemeasuredfromdaystoweeks.Ithinknolongerthanamonthattheextreme,saysDr.Ryan.Dr.Ryansaysifanoutbreakisn'tstoppedorcontrolledin30days,scientistsmaylosethebattle,andnobodyknowswhetherthatcanbedone.HowgoodisDr.Ryan'ssurveillancesystem?Myfearisthatthereareblindspots.Thatthereareblindspotsinoursurveillancesystematnationallevel.Andthatcreatesblindspotsglobally,heexplains.OneofthoseblindspotsisinCambodia,thepoorestoftheSoutheastAsiancountrieswherethevirusismostactive.Migratorywaterfowlhavealreadyinfecteddomesticducksandchickens,amajorsourceofproteinformostthepeoplehere.Manyofthemliveinpovertywithnoaccesst