WHO: World facing polio health emergency
5 May 2014 Last updated at 19:18 BST
The World Health Organization (WHO) has declared the spread of polio is an international public health emergency.
Outbreaks in Asia, Africa and Middle East are an "extraordinary event" needing a co-ordinated "international response", the agency says.
WHO Assistant Director General Bruce Aylward says "one of the deadliest diseases in history has the opportunity to resurge".