Pedzisa mutsara unotevera: Chiremba wokuBritain John Snow akashandisa dhayagiramu yakafanana neyaVoronoi muna 1854 kuratidza kuti vanhu vakawanda vakafa sei mu
Kupararira kwecholera muBroad Street kwakagara pedyo nepombi yemvura yeBroad Street yakanga yabatwa nechirwere kupfuura imwe pombi yemvura ipi neipi.