MAPUTO, Mozambique - Cholera has infected at least 1,052 people in Mozambique's cyclone-hit region, the nation's Health Ministry said on Monday in a new report, marking a massive increase from 139 cases reported four days before, Agence France-Presse reported.

One person has died of cholera, while 97 patients remain in treatment centers, Mozambique's health director Ussein Isse announced. The new figures are an indication that cholera is spreading but is being brought under control, health workers said.

Stephane Dujarric, spokesman for UN chief Antonio Guterres, said there is also a high risk of the spread of infectious diseases including those caused by insects like mosquitoes, with 276 malaria cases reported in cyclone-affected areas, according to The Associated Press.

The overall cyclone death toll in Mozambique has risen to 518. With 259 deaths in Zimbabwe and 56 in Malawi, the three-nation death toll from Cyclone Idai now stands at more than 830. Authorities warn that death estimates are preliminary as receding floodwaters will expose more bodies.

Dujarric said more than 140,000 people in Mozambique are sheltering in 161 sites, including schools and community centers.

He said 11 emergency treatment centers for cholera victims have been established in Beira and other locations and nine are operational.

A mass vaccination campaign is due to be rolled out on Wednesday as authorities and aid workers scramble to avert an epidemic more than two weeks after the devastating cyclone slammed Mozambique.

"A vaccination campaign against cholera, with 900,000 doses of the vaccine, will start on Wednesday," said David Wightwick, the World Health Organization's team leader in Beira. "That should blunt the edge of this outbreak."

More than two weeks after the cyclone hit Beira and swept across central Mozambique, about 98,000 people are in camps for displaced and "living under canvas", he said.

In addition to Mozambican medics, health workers from Portugal, Denmark, Italy and China are helping respond to the crisis.

Sanitary water points and latrines are being constructed throughout Beira by the International Red Cross, which has also established a field clinic in Macurungo, is constructing a field hospital in Nhamatanda and distributing relief supplies to 800 in Buzi, said the organization's spokeswoman, Jana Sweeny.

Cases of cholera, an acute diarrheal disease, have risen dramatically since the first five cases were confirmed last week. Cholera is spread by contaminated water and food. It can kill within hours but is relatively easy to treat.

The US 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 UN World Food Program from King Shaka International Airport in Durban, South Africa, US embassy spokesman Robert Mearkle said.

He said the commodities airlifted from Durban were from the World Food Program's internal stock including rice, dried peas and vegetable oil.

"This lifesaving emergency food assistance will support approximately 160,000 people for one month," Mearkle said.

Agencies