Au-Prince, Haiti, Dhu Al-Qa'dah 17, Oct 25, 2010, SPA -- The confirmation of five cholera cases in Haiti's capital is a "very worrying development," a U.N. spokeswoman told CNN. Public health officials are working to keep the country's cholera outbreak from spreading in Port-au-Prince, Haiti, where tens of thousands of people are still living in sprawling tent cities after January's devastating 7.0-magnitude earthquake. The fast-moving outbreak has claimed at least 253 lives on the impoverished island nation, and another 3,015 cases have been reported, according to Haiti's health ministry. Port-au-Prince could still be safe. The five patients were infected north of the capital, and those confirmed cases do not mean cholera has spread to Port-au-Prince, Imogen Wall, spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs in Haiti, told CNN. "Our response system worked, but obviously this is a very worrying development," she said.