>> oliver, when you talk about the care and dedication that doctors without borders has delivered there, this is a really startling number. the organization has treated more than 23,000 children for cholera just last year alone. why is it so difficult to get the epidemic and cholera under control in and around port-au-prince and in and around haiti. >> cholera in itself is a disease that is easily treatable. however, it is a water-borne disease and in a country where there's a rainy season it becomes very difficult to manage. you can imagine before the earthquake three years ago the water system and the piping was not the best. the earthquake has done nothing to make that better. in fact, today woe still see a lot of negative impact on the water system, on the sanitary system and it just becomes very difficult to manage this and, yes, as you mentioned, we