Polio has almost been wiped out around the world, but it is still a threat in Nigeria, Syria, Pakistan and Afghanistan.
In fact, the Afghan capital Kabul has recorded its first case of polio since the fall of the Taliban in 2001. A 3-year-old girl there was recently diagnosed with the infectious disease.
In response, the health ministry in Afghanistan has ordered a vaccination campaign cross the city. The BBC’s David Loyn reports.