Imagine a killer with the infectiousness of the common cold and power of the Black Death. Imagine something so deadly that it wipes out 90 per cent of those it touches. Imagine an organism against which there is no defence. But you don't need to imagine. Such a killer exists: it is a virus and its name is Ebola. ''The Hot Zone'' tells what happens when the unthinkable becomes reality: when a deadly virus, from the rain forests of Africa, crosses continents and infects a monkey house ten miles from the White House. Ebola is that reality. It has the power to decimate the world's population. Try not to panic. It will be back. There is nothing you can do...