The WHO says the world is in danger. There is a virus called 'Disease X'. Scientists don't know what it looks like. It could spread around the world before we know about it. The WHO said the name 'Disease X' represents any international epidemic from an unknown virus. It has a plan if there is an outbreak.

Disease X could come from many places. A disease could get stronger; terrorists could make bio-weapons; technology could make new viruses. Scientists in the U.S. say that 60 per cent of infectious diseases come from animals. Today, we live in cities and travel the world more. This will make diseases spread quickly.