Patients with cholera symptoms have flooded the run-down medical facilities, as international relief agencies warned of a catastrophic humanitarian situation and urged citizens to exercise hygiene precautions.
"We now are facing a serious outbreak of cholera," said Dominik Stillhart, the director of operations at the International Committee of the Red Cross at a news conference in Sanaa on Sunday.
Citing figures compiled by the Yemeni health ministry, Stillhart said 115 people had died of cholera between April 27 and Saturday.
More than 8,500 suspected cases of the waterborne disease were reported in the same period in 14 governorates across Yemen, Stillhart said, up from 2,300 cases in 10 governorates last week.
Doctors Without Borders (MSF) expressed fears on Sunday that health authorities alone will not be able to deal with the outbreak.
"MSF calls on international organisations to scale up their assistance urgently to limit the spread of the outbreak and anticipate potential other ones," it said in a statement.
This is the second outbreak of cholera, a bacterial infection contracted through ingesting contaminated food or water, in less than a year in Yemen, the Arab world's poorest country.
Yemen is witnessing a devastating war between the Saudi-supported government and Iranian-backed Huthi rebels, and less than half of the country's health facilities are functioning two years into the conflict.
"The humanitarian situation in Yemen is catastrophic," Stillhart said.
Garbage fills streets
"There are up to four cholera patients in one single bed," Stillhart said.
"There are people in the garden, and some even in their cars with the IV drip hanging from the window," he said, adding that the ICRC has intervened with IV fluid, chlorine tablets and oral rehydration salts.
A garbage crisis in the capital caused by municipality trash collectors going on a 10-day pay strike, which ended over the weekend, contributed to the outbreak, said Stillhart.
Piles of garbage had mounted in the capital's streets, with residents and passersby wearing masks to avoid the stench of rotting refuse.
Residents of Sanaa "need to follow the guidelines, like cleaning fruits and vegetables very well and not eating uncovered foods that might be polluted," said Jameel Nashir, Yemen's health chief at the World Health Organisation.
"Additionally, they should use good water from sources that are safe and away from the polluted areas," he told AFP.
Ali al-Washali, a patient who suffered severe diarrhoea, said his neighbourhood has always been supplied with water from artesian wells delivered in tankers without any problems, "except for now, as people are getting sick."
The WHO now classifies Yemen as one of the worst humanitarian emergencies in the world alongside Syria, South Sudan, Nigeria and Iraq.
The ICRC has decided to "significantly expand" operations in Yemen owing to not only cholera but the overall humanitarian situation, Stillhart told reporters.
Critical food imports are also at an all-time low as many of the country's Red Sea ports are blockaded.
The United Nations has warned 17 million people -- equivalent to two-thirds of the population -- are at imminent risk of famine in Yemen.
More than 8,000 people have been killed since the Saudi-led Arab coalition intervened to support Yemen's government in 2015, according to the WHO.
