NDJAMENA, 20 October 2010 (IRIN) - Rising floodwater in Chad's capital N'djamena - coming in the midst of a cholera outbreak - has engulfed household wells and toilets and displaced thousands of people, raising the threat of infection, according to the UN Children's Fund (UNICEF).

People fleeing flooded areas are dispersed, generally seeking shelter with relatives in other parts of the city, so it is difficult to monitor their movement and this complicates cholera control efforts, aid workers in the capital said.

Some 1,500 families have lost their homes in N'djamena's Walia District since the River Chari burst its banks in late September, according to aid workers - and the water continues to rise: "It is up to adults' chests or even necks," said Ngolfou Pierre, head of a Walia neighbourhood flood-response committee.

Cholera has infected communities in N'djamena and other parts of Chad since August, after epidemics in nearby Cameroon and Nigeria and heavy rains. 

Several countries in West and Central Africa have seen cholera and severe flooding this rainy season - notably Benin, where recent flooding has killed at least 43 people and left two-thirds of the country or about 76,000sqkm under water, according to the UN.

In N'djamena aid groups are running hygiene education campaigns and reinforcing water and sanitation facilities, but current conditions favour cholera's spread.

"Cases just keep climbing, despite significant efforts in treatment and prevention by a number of aid agencies," UNICEF water, sanitation and hygiene expert Gambo Nayou told IRIN. He said aid workers standing by at cholera treatment centres go immediately to the home of a new patient to disinfect it and surrounding homes.

"The latest flooding has hit people's access to safe water," he said.

The fact that the water level continues to rise creates a huge risk of contamination at wells and hand pumps due to inadequate sanitation in neighbourhoods, said Zelkifli Ngoufonja of Intermon Oxfam, one of the agencies working on the cholera response

"Many of the displaced are using these open wells."

Deputy Mayor Issa Adjidei told IRIN the authorities and aid agencies were working to ensure the displaced have access to designated safe water areas where tents will be set up.

"Relocate the people, fine - but we must be sure there is adequate drinking water so these displaced communities do not become infected."

Evacuation by boat

Chad Red Cross workers are evacuating residents of flooded areas by pirogue, Bongor Zam Barminas, Red Cross secretary-general, told IRIN. The agency is organizing distributions of rice, mats and other relief supplies provided by the government and aid agencies.

"Many families are living outdoors," Red Cross worker Mahamat Bafoundou told IRIN.

Walia District lies lower than the rest of N'djamena but water from the river is beginning to enter other parts of the capital via drainage canals, Deputy Mayor Adjidei told IRIN. He said local authorities have had to block the canals, which usually serve to discharge water from the city into the river.

"We are just praying it will not rain again."

Families in areas near the river are working around the clock to build up sandbag walls, resident Ngolfou said.

"Nobody sleeps. You'll see people filling sacks with dirt all night. The problem now is that the sacks which used to cost 25 CFA francs (5 US cents) are now at least four times that - if you can find them at all; they're running out."

Another resident, Ali Djibrine, told IRIN: "We have had to break down walls of homes to use them as dams against the water. But it seems every night the level rises."

Flooding has hit 19 of Chad's 22 regions, with cholera outbreaks in six regions, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA). As of 7 October, 3,338 people were infected with cholera - up from 735 on 5 September, with 128 deaths this rainy season. Still the fatality rate is down from 6 percent to 3.8 percent, according to OCHA. The floods have destroyed thousands of hectares of crops.