In 1976 a new virus entered the pantheon of lethal human pathogens – Ebola virus. That year outbreaks in Zaire and Sudan sickened 284 people and killed about half of them. Ebola virus causes an illness that initially resembles a typical intestinal virus, with fever, headache, joint and muscle aches, vomiting and diarrhea. Most patients quickly worsen and develop a rash, easy bleeding, and liver and kidney failure. About two thirds of the people who are infected die. Ebola is transmitted from...