Do people spread disease?
Every day millions of people are moving around the world by air, land and sea, but they may be bringing with them more than just their luggage. For example, during last year's ebola outbreak, there were concerns that air travel would spread the disease from west Africa to other countries, sparking a global pandemic. But were these worries justified? By studying the patterns of 187 diseases in 225 countries, Kris Murray and his team at Imperial College have discovered that it's geography, rather than air travel, that's the most important factor, as he explained to Kat Arney.