Smallpox.

In the third item on the programme Paul Allen looks back at the devastating effects smallpox has had on our history. In the 1960's the World Health Organisation aimed to eradicate smallpox worldwide. Now, although the disease is gone, the virus is still alive - should we kill it once and for all? What are the ethical implications of completely wiping out a living organism? But if we don't eradicate it, we run the risk of it being used as a very powerful biological weapon.