Aid workers in flood-hit Mozambique said they were fighting to contain an outbreak of cholera Wednesday, which has sickened 282 people.
Cholera had struck three districts, a United Nations Children's Fund (UNICEF) representative told AFP.
"We have 282 cases as of today," said Emanuele Capobianco.
The outbreak happened as disaster officials battle floods that have killed 109 people since the start of the rainy season in October and affected at least 240,000 more.
No deaths from cholera had been reported so far, but officials are on high alert.
Cholera is endemic to northern Mozambique and occurs during the rainy season each year.
"At the moment I think the response is ok but we need to keep a very close eye on it," Capobianco said.
"The rains are a factor that could worsen the situation so we need extra caution from the ministry and all partners on the ground," he said.
Rita Almeida, a spokesperson for the countrys disaster management institute, said 240,000 people had been affected by the floods, including 60,000 who had lost their homes.
UN sources have put the number of those affected at 250,000.
Sprawling camps have been set up in the southern Gaza province to accomodate the displaced.
Most of the 109 deaths have been attributed to a flood surge that hit the region in late January.
But the impact of the floods is still being felt across the country.
In northern Zambezia province thousands of vehicles have been left stranded after heavy rains opened up a 25-metre (82 feet) wide crater on the country's main north-south highway.
The crater continues to grow because of the rain, Daniel dos Santos of Mozambique's national road authority told local media.