Severe floods across West Africa after heavy seasonal rains beginning in July 2008 have uprooted more than 200,000 people, according to the U.N. World Health Organisation (WHO).

• Six countries in need of urgent aid
• Fears of waterborne diseases like cholera
• Homes destroyed, bridges and cellphone networks down

Six countries - Benin, Burkina Faso, Mali, Mauritania, Niger and Togo - need urgent aid after floods caused widespread damage and massive displacement, according to WHO.

Some 150,000 are displaced in Benin alone, it said. A climatologist there said more flooding was likely during this year's rainy season, which typically runs from May to September.

Liberia is also experiencing the worst storms in its recent history, with about 1,000 people pushed out of their homes, U.N. news service IRIN reported.

In Togo, bridges have collapsed and most of the cell phone network cut off.

In Niger, it said more than 40,000 people had been affected, with hundreds camping in schools. Aid workers say there were no plans for what to do when the school year begins in October.

Relief agencies were distributing mosquito nets in the shelters.

Mosquito-borne malaria is the main cause of illness and death in West Africa. Meningitis, cholera and yellow fever also claim scores of lives each year in the region.

The floods have increased the risk of waterborne diseases spreading, and several countries - Guinea-Bissau in particular - were already fighting battling cholera outbreaks before the waters rose.

Floods in 2007 displaced more than 1 million people. Ghana was among the worst-hit, along with Burkina Faso, Togo and Mali.

Benin, Gambia, Guinea, Ivory Coast, Liberia, Mauritania, Niger, Nigeria, Senegal and Sierra Leone were also affected.

Experts say local people and authorities need to take action to stop the regular floods reaching disaster level. They advise conducting emergency drills, encouraging people to build on higher ground when possible or build dykes when not, cleaning river banks, and planting trees and mangroves to help prevent landslides to combat dangers of cutting down trees for charcoal.

West Africa is home to some of the world's least developed and poorest countries. Many households in the normally arid Sahel belt south of the Sahara desert already face difficulties finding food.