Rubuta ci gaba don wannan sakin layi - Kafin gano wata cuta mai sa kamuwa da cuta, ana tunanin alamun cutar kwalara na faruwa ne saboda yawan bile a cikin mai haƙuri; cutar kwalara ta samo sunanta daga kalmar Helenanci "choler" ma'anar bile. Wannan ka'idar ta yi daidai da barkwanci, kuma ta kai ga irin wannan aikin likita kamar zubar da jini. An fara ba da rahoton kwayar cutar a cikin 1849 ta Gabriel Pouchet, wanda ya gano shi a cikin najasa daga marasa lafiya da cutar kwalara, amma bai fahimci mahimmancin wannan kasancewar ba. Masanin kimiyya na farko da ya fahimci muhimmancin "Vibrio cholerae" shi ne masanin ilimin lissafi na Italiya Filippo Pacini, wanda ya buga cikakken zane na kwayar halitta a cikin "Microscopical observations and pathological deductions on cholera" a shekara ta 1854. Ya wallafa ƙarin takardu a cikin 1866, 1871, 1876 da 1880, waɗanda masana kimiyya suka yi watsi da su. Ya bayyana daidai yadda ƙwayoyin cuta suke jawo zawo, kuma ya ƙirƙiro hanyoyin magani da aka gano suna da amfani. Duk da yake an san taswirar cututtukan cututtukan cututtukan John Snow, kuma ya haifar da cire maɓallin famfo na Broad Street, misali 1854 Broad Street cutar kwalara
Ka yi haƙuri. A shekara ta 1874, wakilan masana kimiyya daga ƙasashe 21 suka yanke shawara cewa cutar kwalara tana faruwa ne saboda guba da ke cikin mahalli daga "miasmatas", ko kuma girgije na abubuwa marasa kyau da ke yawo a cikin iska. A cikin 1884, Robert Koch ya sake gano "Vibrio cholerae" a matsayin abin da ke haifar da cutar kwalara. Wasu masana kimiyya sun yi adawa da sabon ka'idar, har ma sun sha al'adun kwalara don musanta shi: