The World Health Organization says a polio epidemic has been successfully stopped in ten countries in west and central Africa.
Among the nations now declared polio-free are Cameroon, Ghana, Mali and Togo. However, at least five other countries in the region, including Nigeria, are still affected.
The WHO is starting a new vaccination campaign in 28 African countries.
However, the organisation's polio co-ordinator, Bruce Aylward, said its success was by no means guaranteed.
