UN Secretary-General Antonio Guterres has asked all the 193 UN member states to inform him by March 6 if they intend to make voluntary financial contributions to the efforts to carry out a new UN plan to tackle cholera in Haiti, UN spokesman Stephane Dujarric said here Friday. Under the new approach, the United Nations is intensifying support to the Haitian government in building sound water, sanitation and health systems — the best long-term defence against cholera and other water-borne diseases, Dujarric said.