Yemeni doctor Mohammed Abdul-Mughni described the rising number of cholera cases he was treating as "disastrous."
Two weeks later, he also died of the disease.
Yemen has been at war since 2015. The conflict has led to food shortages and put 10 million people at risk of famine.
The United Nations says it has recorded 110,000 probable cholera cases and 200 deaths in three months. UN officials say the disease is spreading like "wild-fire."
Cholera usually spreads in unclean water and contaminated food. One sign of infection is severe diarrhea.
Abdul-Mughni had been working in a diarrhea treatment center at a hospital in Sanaa. About 120 to 150 severe cases arrive there every day.
"We are taking in patients around the clock, constantly...Cholera is spreading widely now," said Ismail Mansoury. He is a doctor who worked with Abdul-Mughni. Mansoury told the Reuters news agency he had seen about 1,100 cholera patients in the past two weeks.
Cholera causes severe diarrhea and fluid loss. It can kill within hours. Children, older adults and those who are weak from hunger are most at risk.
The diarrhea treatment center has temporary shelters, outdoor restrooms and overworked employees. Women receiving intravenous fluids take up every place out of the sunshine. Children lie on the ground. A man helps a boy to use a restroom.
Many of those arriving are in shock or suffer from kidney failure. They are so dehydrated it is difficult to give them lifesaving fluids.
As the Iran-backed Houthis fight the Saudi-backed Yemeni government, the country has collapsed. The war has destroyed Yemen's healthcare system and the economy. People must travel great distances to find simple medical care.
"Hardly a drop of water"
The 70-year-old mother of Mona Ali's husband traveled 25 kilometers to the hospital in a bus after three days of uncontrollable diarrhea and being sick.
Ali had cholera two months ago and recovered at home. She told Reuters her family was poor and had to borrow money to bring her mother-in-law to the hospital.
"If there was food the body would be stronger," she said.
Water is not easily found in Yemen, the poorest nation on the Arabian Peninsula. Pumps are needed in many parts of the country to bring water up from the ground. Clean water has become costly because of rising fuel prices.
Ali said her village cannot pay for the fuel needed to pump the water. "We end up taking it from the wells, even though...it harms us," she said.
The cholera outbreak is also a sign of the war's destruction of public health systems. Human waste has polluted so much water that it is ending up in the water used for farming, explained Tarik Jasarevic. He is a spokesman for the UN's World Health Organization.
To slow the disease's spread, diggers have been removing waste from the streets of Sanaa and spraying areas with disinfectant.
Yemen's war began in late 2014 when Houthi forces pushed the government of President Abdul-Rabbu Mansour Hadi out of Sanaa. A Saudi-backed alliance of Yemeni and Arab forces began fighting in March 2015 to re-establish him as president.
The Houthis say their revolution is against corruption. They control Sanaa and most population centers.
The war has slowed the movement of aid, fuel and food. It has reduced imports and caused severe inflation. Those with government jobs have not been paid in months and are urgently looking for food.
Mohammad Habab is a 34-year-old university-educated father of three. He works for a state-operated company, but has not been paid.
His three-year-old daughter Zainab was receiving fluids nearly 80 kilometers from home after developing signs of cholera. Habab blames her condition on a lack of clean water and food.