When a man crashes his car into a petrol station, he brings with him the foul corpses of his wife and daughter. He dies and it doesn't take long for the plague which killed him to spread across America and the world.
I've had the same copy of this book since I was around 17 years old. It is an old favorite that I come back to time and time again. The only bad thing is when I read it I get really nervous around anyone with a cold. :)