This is a zombie lie that never ever stops. You can't trust whatever psycho-website you got that misinformation from.
DDT was NEVER banned for public health purposes in Africa or anywhere in the Developing World.
It was restricted for use in agriculture to ensure --in part-- that it continued to be useful for public health. As far back as the late 1950s it was known that mosquitos easily developed resistance to DDT and other insecticides.