Nearly 600,000 West Africans are affected by floods, following three months of rain. The unusually heavy rainy season is expected to continue through the end of September.
The latest United Nations assessment of West African flooding says more than 150 people have been killed - many in Sierra Leone - and that others there and in Senegal, Burkina Faso, Ghana and Niger are also seriously affected by rising flood waters.
Eight people are dead in Burkina Faso, where meteorologists say 263 millimeters of rain fell in just 12 hours, last week. That is one-quarter of the country's average annual rainfall. Half of the capital, Ouagadougou, is affected by flooding that has damaged the university hospital.
Yvon Edoumou is the West Africa spokesman for the U.N. Office for the Coordination of Humanitarian Affairs.
"The hospital was one of the main hospitals in Ouagadougou where thousands of people were treated each day," Edoumou said. "So clearly that is a major concern for us. If you think in terms of just basic health services or even more acute health conditions, there is a fear that people who were there at the time of the flooding are not getting the treatment that they should be."
More than 150,000 people in Burkina Faso are homeless - many now living in schools and community centers. Those facilities are so overcrowded that men are sleeping outside, exposed to malarial mosquitoes breeding in standing water.
"Anytime anyone is sleeping outside, particularly in West Africa which is very well known for its malaria, you are clearly exposing yourself to that disease and other diseases," Edoumou said. "If you add the fact that there is water all over the city, then the risks are even higher. Now, the reason we have women and children sleeping inside is because we consider them to be the most vulnerable."
In Senegal, the new U.N. assessment says more than 260,000 people are affected by weeks of heavy rain, most living in poor neighborhoods built on lowlands outside the capital, Dakar.
Returning from a month's holiday in Europe, President Abdoulaye Wade says he sympathizes with the suffering of those whose homes are flooded but says this year's rains are a mixed blessing as they will lead to bigger harvests that will make Senegal nearly food self-sufficient.
Elsewhere, farmers have not fared as well. In Niger, the city of Agadez lost close to 400 hectares of land used for farming and cattle.
Edoumou says the rains may worsen food insecurity in West Africa, especially in Sahelian countries where small-scale farmers have few reserves.
"When you have a situation like this occur, you are bound to have a situation down the line where there could be a shortage in food, which can also trigger other negative situations, such as malnutrition, for example, or insufficient food for cattle, which is also another important economic sector in West Africa," Edoumou said.
Two years ago, flooding in West Africa killed 300 people and affected more than 800,000 others. Rains are expected to continue throughout the region until the end of the month.