Uhudo or ukukhishwa yisisu yisimo sokukaka into ethambile noma engamanzi okungenani izikhathi ezintathu ukunyakaza kwesisu ngosuku. Kujwayele ukuthi kube yizinsukwana ezimbalwa kanti futhi kungaholela ekuphelelweni amanzi emzimbeni ngenxa yokulahlekelwa amanzi amaningi. Izimpawu zokuphelelwa amanzi emzimbeni zijwayele ukuqala ngokuphelelwa ukunwebeka okujwayelekile kwesikhumba kanye nokushintsha kwendlela umuntu ayiyo. Lokhu kungaqhubeka kunciphise ukuchama, ukulahlekelwa umbala wesikhumba, ukushaya kwenhliziyo ngamandla, kanye ukwehla kwezinga lokuphendula ngenkathi kuya kulokhu kukuqinisa.Amakaka athambile kodwa angemanzi ebantwaneni abancela ubisi lwebele, kungenzeka, kube yinto ejwayelekile. Imbangela ejwayelekile kuvamise ukuba ukutheleleka ngesifo samathumbu kungaba ngenxa yegciwane, ibhaktheriya, isilwanyana esiphila ngokudla igazi, noma isimo esaziwa gastroenteritis.Lokhu kutheleleka ngezifo kuvamise ukutholakala ekudleni noma emanzini angcoliswe amakaka, noma komunye umuntu naye othelelekile. Kungahlukaniswa kube yizinhlobo ezintathu: uhudo olungamanzi lwesikhathi esifishane, uhudo olunegazi lwesikhathi esifishane, kanti uma kuqhubeka kuze kuphele amasonto angaphezulu kwamabili, kubizwa ngohudo olubeleselayo. Uhudo olungamanzi lwesikhathi esifishane lungaba yimbangela yokuthelelwa ikholera. Uma kunegazi kuphinde kwaziwe ngokuthi dysentery. Zikhona nezinye izinto eziningi ezingabanga uhudo kodwa ezingathelelani ngezifo ezifana: hyperthyroidism, okungezwani ne-esidi, isifo sokuvuvukala kwamathumbu, imithi eminingi, kanye nesifo samathumbu angakwazi ukubekezelela okuthile phakathi kokunye. Ezikhathini eziningi izintwana ezihlala emakakeni azidingeki ukuze kutholakale ukuthi yizo yini imbangela.