Ka cika wannan magana: A ƙarni na 19, Biritaniya ce cibiyar ci gaba mai sauri na birane, kuma a sakamakon haka, matsaloli da yawa na kiwon lafiya da tsabta sun bayyana, alal misali ɓarkewar cutar kwalara da annoba. Wannan ya haifar da Birtaniya ta taka muhimmiyar rawa a ci gaban lafiyar jama'a. Kafin a gano alaƙar da ke tsakanin gurɓataccen ruwan sha da cututtuka, kamar su kwalara da wasu cututtuka da ake samu ta ruwa, an yi amfani da ka'idar miasma don a ba da hujjar ɓarkewar waɗannan cututtuka. Ka'idar Miasma ita ce ka'idar cewa wasu cututtuka da cututtuka sune samfurori na "mummunan iska". Binciken likitan John Snow a Burtaniya a lokacin barkewar cutar kwalara ta 1854 Broad Street ya fayyace alaƙar da ke tsakanin cututtukan ruwa da gurɓataccen ruwan sha. Ko da yake ba a riga an ƙirƙiro ra'ayin ƙwayoyin cuta ba tukuna, abin da Snow ya lura ya sa ya yi watsi da ra'ayin ƙwayoyin cuta. Rubutun sa na 1855 "A kan Hanyar Sadarwar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar Cutar A lokacin annobar 1854, ya tattara kuma yayi nazarin bayanan da suka tabbatar da cewa mutanen da suka sha ruwa daga gurbataccen tushe kamar su
Wutar Broad Street ta mutu ne daga cutar kwalara a mafi yawan lokuta fiye da wadanda suka sami ruwa a wani wuri. Bayanansa sun shawo kan majalisa na gari don kashe famfon ruwa, wanda ya kawo karshen barkewar cutar.