Former employees of a scandal-hit charity founded by U2 singer Bono have warned that more serious revelations of mismanagement and bullying have yet to be made public.

Ebola represents a threat to all humanity and an outbreak of the virus in five West African countries will likely spread to more, American officials warned.

President Barack Obama is to announce a new initiative to double access to electric power in sub-Saharan Africa, part of his effort to build on the legacy of equality and opportunity forged by his personal hero, Nelson Mandela.