Saudi Arabia says it has donated $67m (£52m) to combat a cholera outbreak in Yemen which has hit more than 200,000 people and been declared the "world's worst" by global health bodies. More than 5,000 people are contracting the disease every day in Yemen and UNICEF and the World Health Organisation (WHO) said it was growing almost impossible to control its spread. Cholera has already killed 1,300, a quarter of them children, officials said. More than 200,000 cases have been diagnosed, and this is expected to rise to 300,000 by September, WHO senior medical consultant Dr Xavier de Radiguès told CNN. UNICEF, the WHO and its partners will receive the $66.7 million from Saudi Arabia to spend on countering the epidemic. Cholera is easily prevented by basic sanitation such as washing hands and food with clean water. But it spreads fast in war zones, where contaminated water and poor hygiene are rampant.