Free and clear (almost) Africa passed an important milestone in July, one that marked 12 months since a case of polio had been reported on the continent. Another three years have to pass, however, before Africa is finally declared polio-free. According to Conversation Africa, the last polio case was reported in Nigeria in July 2014. Globally, cases have dropped almost 100% – from about half a million in the 1980s to only 34 so far this year. The dramatic reduction in cases of the disease can be attributed to the use of two vaccines developed more than 50 years ago. While the polio virus continued to circulate around the continent until last year, with five countries declaring outbreaks, that number is still considerably lower than the 14 countries affected by the disease in 2004. 11 August 2015 Image: Gallo/GettyImages