Beira, Mozambique -- Mozambique's cyclone-hit city of Beira has confirmed its first death from cholera, as the number of cases of the disease has jumped to 517. To control the outbreak emergency clinics have been set up across Beira, a city of 500,000, said Mozambican national health director Ussene Isse, according to broadcaster TVM.

Cases of the acute diarrheal disease have risen dramatically since the first five cases were confirmed last week. Cyclone Idai severely damaged the water system for Beira, a city of 500,000, when it hit on March 14.

Some 900,000 cholera vaccine doses were set to arrive on Monday, according to the World Health Organization.

Get Breaking News Delivered to Your Inbox

Cholera is spread by contaminated water and food. It can kill within hours but is relatively easy to treat.

The overall cyclone death toll in Mozambique is now 518. With 259 deaths in Zimbabwe and 56 in Malawi, the three-nation death toll is more than 815.

Authorities warn the tolls are preliminary as flood waters recede and reveal more bodies.

Rush to get help in

The Chinese government has sent doctors and emergency workers to fight the cholera outbreak in Beira and Chinese aid workers sprayed anti-cholera disinfectant in parts of the port city.

The U.S. military joined the international humanitarian aid efforts to Mozambique by airlifting food and relief supplies from South Africa.

Round-the-clock flights are delivering supplies from the U.N. World Food Program from King Shaka International Airport in Durban, South Africa, said Robert Mearkle, U.S. embassy spokesman.

He said the commodities airlifted from Durban were from the World Food Program's internal stock.

"Separately from these shipments, the United States has provided nearly $3.4 million in additional funding for the World Food Program to deliver approximately 2,500 metric tons of rice, peas, and vegetable oil to affected people in Sofala, Zambezia, and Manica provinces," said Mearkle. "This lifesaving emergency food assistance will support approximately 160,000 people for one month."

Cholera spreads "extremely fast"

Beira's crowded, poor neighborhoods are especially at risk. Doctors Without Borders has said it is seeing some 200 likely cholera cases per day in the city, where relief workers are hurrying to restore the damaged water system and bring in additional medical assistance.

A medical staff member wears a protective mask as he assists a man arriving at a cholera treatment center set up in the aftermath of Cyclone Idai in Beira, Mozambique, March 29, 2019. REUTERS

Cholera is a major concern for the hundreds of thousands of cyclone survivors in the southern African nation now living in squalid conditions in camps, schools or damaged homes. Some drink from contaminated wells or filthy, stagnant water.

As health responders stress the need for better disease surveillance, the United Nations' deputy humanitarian coordinator in Mozambique, Sebastian Rhodes Stampa, has said all cases of diarrhea are being treated as though they are cholera.

Cholera is endemic to the region, and "it breaks out fast and it travels extremely fast," he told reporters.

Doctors Without Borders has said other suspected cholera cases have been reported outside Beira in the badly hit areas of Buzi, Tica and Nhamathanda but the chance of spread in rural areas is smaller because people are more dispersed.

Mozambican officials have said Cyclone Idai destroyed more than 50 health centers in the region, complicating response efforts.

The United Nations has said some 1.8 million people need urgent help across the sodden, largely rural region.