unit 1 文档1854 broad street cholera outbreak（人教）

《unit 1 文档1854 broad street cholera outbreak（人教）》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、1854BroadStreetcholeraoutbreakBroadwickStreetshowingtheJohnSnowmemorialandpubThe1854BroadStreetcholeraoutbreakwasasevereoutbreakofcholerathatoccurrednearBroadStreet(nowrenamedBroadwickStreet)inSohodistrictofLondon,Englandin1854.ThisoutbreakisbestknownforJohnSnow'sdiscoverythatcholerais

2、spreadbycontaminatedwater.BackgroundInthemid-19thcentury,theSohodistrictofLondonhadaseriousproblemwithfilthduetothelargeinfluxofpeopleandalackofpropersanitaryservices.Manycellars(basements)hadcesspoolsofnightsoilunderneaththeirfloorboards.Sincethecesspoolswereoverrunning,theLondongover

3、nmentdecidedtodumpthewasteintotheRiverThames.Thiscausedmassivewatercontaminationandledtothecholeraoutbreak.OutbreakOn31August1854,afterseveralotheroutbreakshadalreadyoccurredelsewhereinthecity,amajoroutbreakofcholerastruckSoho.DrSnowlatercalledit"themostterribleoutbreakofcholerawhichev

4、eroccurredinthekingdom."Overthenextthreedays127peopleonornearBroadStreetdied.Inthenextweek,threequartersoftheresidentshadfledthearea.By10September,500peoplehaddiedandthemortalityratewas12.8percentinsomepartsofthecity.Bytheendoftheoutbreak616peopledied.JohnSnowInvestigationOriginalmapby

5、Dr.JohnSnowshowingtheclustersofcholeracasesintheLondonepidemicof1854Snowwasaskepticofthethen-dominantmiasmatheorythatstatedthatdiseasessuchascholeraortheBlackDeathwerecausedbypollutionoranoxiousformof"badair".Thegermtheorywasnotwidelyacceptedbythistime,soSnowwasunawareofthemechanismbyw

6、hichthediseasewastransmitted,butevidenceledhimtobelievethatitwasnotduetobreathingfoulair.HefirstpublicizedhistheoryinanessayOntheModeofCommunicationofCholerain1849.In1855asecondeditionwaspublished,withamuchmoreelaborateinvestigationoftheeffectofthewater-supplyintheSoho,Londonepidemicof

7、1854.Bytalkingtolocalresidents(withthehelpofReverendHenryWhitehead),heidentifiedthesourceoftheoutbreakasthepublicwaterpumponBroadStreet(nowBroadwickStreet).[1]AlthoughSnow'schemicalandmicroscopeexaminationofasampleoftheBroadStreetpumpwaterwasnotabletoconclusivelyproveitsdanger,hisstu