More than half a million people in Yemen have now been infected with cholera since the epidemic broke out in April, the World Health Organisation (WHO) has said, as medical workers on the ground struggle to cope with up to 5,000 new cases a day.

A total of 1,975 people have now died from the acute diarrhoeal infection caused by ingestion of contaminated food or water, it said in a statement on Monday. Last month, the organisation estimated that around half of cases and a quarter of the dead so far are children under the age of 15.

“The spread of cholera has slowed significantly in some areas compared to peak levels but the disease is still spreading fast in more recently affected districts, which are recording large numbers of cases,” the statement said, reporting a total of 503,484 infected patients.

Yemen crisis: More than one million children suffering from malnutrition

Two years of civil war has decimated Yemen’s infrastructure and put the 27-million strong population on the brink of famine.

The collapse of the medical system has allowed cholera to balloon across the entire country. Aid organisations are struggling to reach people in remote, recently hit areas, and critical medical as well as food supply lines are being strangled by the Saudi-led blockade on Yemen’s airspace and ports.

Less than half of the country’s medical centres are still functional, 14.5 million people don’t have regular access to clean water, and in several provinces health and sanitation workers have not been paid in almost a year.

While it is easily preventable and treatable in hygienic conditions, cholera can kill the old, young and otherwise sick in hours if fluids are not replaced.

The situation in Yemen Show all 14 1 /14 The situation in Yemen The situation in Yemen Houthi supporters trample on a US flag during a gathering mobilizing more fighters into several Yemeni battlefronts, in Sana'a, Yemen EPA The situation in Yemen People carry the coffins of men, who were killed in the recent Saudi-led airstrikes during their funeral, in the Old City of Sanaa, Yemen AP The situation in Yemen Pro-government fighters give food to Yemeni children on the road leading to the southwestern port city of Mokha. Yemeni rebels are putting up fierce resistance in a key Red Sea port city where they are encircled by pro-government force Getty Images The situation in Yemen A Yemeni stands in front of a graffiti protesting US military operations in war-affected Yemen, in Sana'a, Yemen. According to reports, US Special Forces troops allegedly disembarked from US helicopters in the Yemeni town of Yakla and attacked several houses belonging to members of the terrorist group Al-Qaeda, killing three high-ranking Al-Qaeda members and nine civilians, six women and three children. One American serviceman has been killed and three injured in the attack EPA The situation in Yemen US Special Forces troops allegedly disembarked from US helicopters in the Yemeni town of Yakla and attacked several houses belonging to members of the terrorist group Al-Qaeda, killing three high-ranking Al-Qaeda members and nine civilians, six women and three children. One American serviceman has been killed and three injured in the attack EPA The situation in Yemen A Yemeni female fighter supporting the Shiite Huthi rebels, and carrying weapons used for ceremonial purposes, takes part in an anti-Saudi rally in the capital Sanaa Getty Images The situation in Yemen Yemeni female fighters supporting the Shiite Huthi rebels, and carrying weapons used for ceremonial purposes, take part in an anti-Saudi rally in the capital Sanaa Getty Images The situation in Yemen A boy shouts slogans next to pro-Houthi fighters, who have been injured during recent fighting, during a rally held to honour those injured or maimed while fighting in Houthi ranks in Sanaa, Yemen Reuters The situation in Yemen Balls of fire and smoke rise from a Houthi-held military camp following alleged Saudi-led airstrikes, in Sana'a, Yemen EPA The situation in Yemen Yemenis search under the rubble of damaged houses following reported Saudi-led coalition air strikes on the outskirts of the Yemeni capital Sanaa Getty Images The situation in Yemen A Yemeni boy looks on as Yemenis search under the rubble of damaged houses following reported Saudi-led coalition air strikes on the outskirts of the Yemeni capital Sanaa Getty The situation in Yemen A Yemeni boy sits amidst the rubble of damaged houses following reported Saudi-led coalition air strikes on the outskirts of the Yemeni capital Sanaa AFP/Getty The situation in Yemen Marine One with US President Donald Trump flies with a decoy and support helicopters to Dover Air Force Base in Dover, Delaware, for the dignified transfer of Navy Seal Chief Petty Officer William 'Ryan' Owens who was killed in Yemen Getty Images The situation in Yemen US President Donald Trump aboard the Marine One to greet the remains of a US military commando killed during a raid on the al Qaeda militant group in southern Yemen on Sunday, at Dover Air Force Base, Delaware, US Reuters

The UK’s Department for International Development (DFID) said last week that it will provide chlorine tablets and hygiene kits for 500,000 people, and rehabilitate seven health centres and 35 oral rehydration points which are expected to help a futher 250,000 in three of the worst affected areas - but NGOs warn much more is needed to effectively tackle the crisis.

“Yemen’s health workers are operating in impossible conditions. Thousands of people are sick, but there are not enough hospitals, not enough medicines, not enough clean water”, said Dr Tedros Adhanom Ghebreyesus, WHO’s Director-General.

“These doctors and nurses are the backbone of the health response – without them we can do nothing in Yemen. They must be paid their wages so that they can continue to save lives.”

Saudi Arabia and its regional partners have used the spectre of Iranian influence to justify an extensive bombing campaign on Yemen’s Shia Houthi rebels, who control the capital Sanaa, at the request of the exiled, internationally recognised Yemeni President Abdrabbuh Mansour Hadi.

The intense Saudi-led bombing campaign – which has in some cases targeted civilian buildings such as hospitals and funeral gatherings – has killed thousands of civilians.

Western governments including the UK have been heavily criticised for selling weapons export licences to Saudi Arabia, which rights groups say are destined for use in Yemen’s war.

Officials within former US President Barack Obama’s administration worried the sales could amount to complicity in war crimes.

The UN estimates $2.1bn (£1.6bn) is needed to stop Yemen become a completely failed state, but donor governments only pledged half that amount at an aid conference in Geneva in April.