( CNN ) -- Torrential rains and flooding since June have affected 600,000 people in 16 West African nations , the United Nations reported Tuesday . People walk in the flooded streets of Ouagadougou , Burkina Faso , last week . The worst hit have been Burkina Faso , Senegal , Ghana and Niger , said Yvon Edoumou , a spokesman for the U.N. Office for the Coordination of Humanitarian Affairs , or OCHA , in the Senegalese capital , Dakar . So far , 159 people have died , he said . Sierra Leone has also been hard hit , according to the U.N. Edoumou said removing water from flooded areas is a top priority , but powerful pumps are in short supply . `` Some people refused to leave their homes so they are living in floodwaters , '' he said . The United Nations has not yet received reports of waterborne diseases , but Edoumou said a real threat exists of diarrhea or , worse , cholera . The U.N. World Food Programme said Tuesday it has begun distributing food to tens of thousands of homeless flood victims . WFP has set a goal of feeding 177,500 people , mainly in Ouagadougou , the capital of Burkina Faso , where 150,000 people have been affected and key infrastructure -- including a central hospital , schools , bridges and roads -- has been damaged . The flooding in Burkina Faso is the worst in 90 years , WFP said . Many of those in Ouagadougou most needing help were already receiving aid from WFP , but those rations were lost in the floodwaters , the U.N. reported . `` It is always the poor and vulnerable who suffer the most from floods like these as their few remaining assets are swept away , leaving them hungry and destitute , '' WFP Executive Director Josette Sheeran said . Roads and buildings have been ruined from Mauritania to Niger , the U.N. reported . In Agadez , Niger , a town about 458 miles ( 738 km ) north of the capital , Niamey , close to 988 acres ( 400 hectares ) of vegetable crops and hundreds of livestock were washed away . Herve Ludovic de Lys , head of OCHA in West Africa , said natural disasters have a lasting effect that unravels years of progress against poverty . `` The situation is very worrying , '' he said in an OCHA statement issued Tuesday . The rainy season in West Africa begins in June and continues through late September . In 2007 , 300 people died and 800,000 were affected by the storms . This year , fears abound that more heavy rain will fall in already waterlogged areas . Despite the misery , Edoumou said the rains are a mixed blessing for countries dependent on agriculture . The harvest this year will be more bountiful , he said .
U.N. begins distributing food to tens of thousands of homeless flood victims . U.N. says 159 have died due to flooding ; key infrastructure damaged . Waterborne diseases like cholera are a concern , U.N. official says . `` It is always the poor and vulnerable who suffer the most from floods , '' official says .