Nyorai kupfuurira kweiyi ndima - Broad Street yakanga ine mukurumbira wakashata senzvimbo yekuputika kwa 1854
yekorera. Dr. John Snow vakatevera kupararira kwechirwere ichi kusvika papombi yemvura yomunharaunda iri mumugwagwa, uye vakaidzima. Nguva iyi isati yasvika, chirwere chacho chaifungidzirwa zvikuru kuti chinokonzerwa ne'miasma' inofambiswa nemhepo; zvakawanikwa naSnow zvakaratidza kuti chinoparadzirwa nemvura.