In the cholera-stricken refugee camps of western Sudan, every second is infected by fear. Faster than a person can boil water over an open flame, the flies descend, and everything is contaminated once more.

Cholera is ripping through the camps of Tawila in Darfur, where hundreds of thousands of people have been left with nothing but the water they can boil to serve as both disinfectant and medicine.

“We mix lemon in the water when we have it and drink it as medicine,” said Mona Ibrahim, who has been living for two months in a hastily erected camp in Tawila.

“We have no other choice,” she said, seated on the bare ground.

Nearly half a million people sought shelter in and around Tawila from the nearby besieged city of el-Fasher and the Zamzam displacement camp in April, following attacks by the paramilitary Rapid Support Forces (RSF), at war with Sudan’s army since April 2023.

The first cholera cases in Tawila were detected in early June in the village of Tabit, about 25km (16 miles) south, said Sylvain Penicaud, a project coordinator for Doctors Without Borders, known by its French initials MSF.

“After two weeks, we started identifying cases directly in Tawila, particularly in the town’s displacement camps,” said Penicaud.

In the past month, more than 1,500 cases have been treated in Tawila alone, he said, while the United Nations children’s agency says about 300 of the town’s children have contracted the disease since April.

Across North Darfur state, more than 640,000 children under the age of five are at risk, according to UNICEF.

By 30 July, there were 2,140 infections and at least 80 deaths across Darfur, UN figures show.

Cholera is a highly contagious bacterial infection that causes severe diarrhoea and spreads through contaminated water and food.

Causing rapid dehydration, it can kill within hours if left untreated, yet it is preventable and usually easily treatable with oral rehydration solutions.

More severe cases require intravenous fluids and antibiotics.

Ibrahim Adam Mohamed Abdallah, UNICEF’s executive director in Tawila, said his team “advises people to wash their hands with soap, clean the blankets and tarpaulins provided to them, and how to use clean water”. But in the makeshift shelters of Tawila, even those meagre precautions are out of reach.

Water is often fetched from nearby natural sources – often contaminated – or from one of the few remaining shallow, functional wells.

“It is extremely worrying,” said MSF’s Penicaud, but “those people have no (other) choice.”

The UN has repeatedly warned of food shortages in Tawila, where aid has trickled in, but nowhere near enough to feed the hundreds of thousands who go hungry.

Sudan’s conflict, now in its third year, has killed tens of thousands and created the world’s largest displacement and hunger crises, according to the UN.

In Tawila, health workers are trying to contain the cholera outbreak – but resources are stretched thin.

MSF has opened a 160-bed cholera treatment centre in Tawila, with plans to expand to 200 beds, and a second centre in Daba Nyra, one of the most severely affected camps, but both are already overwhelmed, said Penicaud.

Meanwhile, aid convoys remain largely paralysed by the fighting, and humanitarian access has nearly ground to a halt.

Armed groups, particularly the RSF, have blocked convoys from reaching those in need.

The rainy season, which peaks this month, may bring floodwaters that further contaminate water supplies and worsen the crisis.