War-battered Yemen has been hit with more than 460,000 suspected cholera cases so far this year -- a sharp rise from the 380,000 cases for all of 2018, the United Nations said Monday. UN deputy spokesman Farhan Haq said the increased number of cases has led to 705 apparent cholera deaths since January, dramatically higher than the 75 deaths in the same period last year. Haq said the spread of cholera across the country has been accelerated by recent flash flooding, poor maintenance of waste management systems and a lack of access to clean water for drinking or irrigation. The United Nations and its partners are operating nearly 1,200 cholera treatment facilities across Yemen, but Haq said that "funding remains an urgent issue." The UN humanitarian appeal for $4.2 billion to help more than 20 million Yemenis this year is only 32 per cent funded. The conflict in Yemen began with the 2014 takeover of the capital, Sanaa, by Iranian-backed Houthi Shiite rebels, who toppled the government of Abed Rabbo Mansour Hadi. A Saudi-led coalition allied with Hadi's internationally recognized government has been fighting the Houthis since 2015.