Toll from cholera outbreak in Lake Chad region now more than 500

More than 500 people have died from cholera in the Lake Chad region since the start of the year, representing the worst outbreak to hit the area in four years, the UN said on Wednesday.

"Over 27,000 cholera cases and 510 deaths have been reported as of week 35 in Lake Chad Basin," the Office for the Coordination of Humanitarian Affairs (OCHA) said in a report.

"This is 10 times more than the average cholera caseload over the past four years," it said.

It said more than six million people could be affected by the outbreak without urgent action to control it.

"The region is facing floods and heavy rains, creating an ideal environment for the outbreak to spread," OCHA warned.

"The last two major outbreaks in the region were in 2010 and 2014. An outbreak in 2018 is consistent with the four-year cycle."

The Lake Chad region straddles parts of Nigeria, Cameroon, Chad and Niger, which are also grappling with a jihadist insurgency

OCHA said Nigeria, Africa's most populous nation, was the worst-hit with 24,000 cases, and said immediate action was needed to stem the disease.

Cholera is caused by a bacterium transmitted through contaminated food or drinking water. It causes acute diarrhoea, with children particularly at risk.

Water-borne diseases are a constant threat in the Lake Chad region because of a lack of adequate sanitation as well as stagnant groundwater during the rainy season.