Syria's water pipes and pumping stations have been ravaged by more than a decade of war and a drought this year left levels in its main river, the Euphrates, particularly low.
Nabbough al-Awwa, an eye, nose, and throat doctor in Damascus, said that dumping solid waste into stagnant waters had contributed to the spread.
"If the river is running, it's fine. But when the water levels got low because of the rising temperatures in a lot of countries in the world, these bacteria started to proliferate and spread," Awwa told Reuters.
With farmers relying on untreated river water, vegetables quickly became contaminated and the virus spread to the cities, he said.
Shops and restaurants in the capital have tweaked their menus to protect their customers.
"We stopped using leafy greens for the sake of public health," said Maher, who runs a falafel shop in Damascus.
The capital remains relatively shielded, according to WHO data, with the highest case numbers recorded in the vast desert province of Deir Ezzor in the east and Raqqa and Aleppo in the north – which rely on the Euphrates the most.
United Nations agencies have mostly been trucking water to affected communities and disbursing sterilisation tablets. But to keep up their efforts, the U.N. children's agency says it still needs around $9 million in funds to get it to the end of the year.
