Read this excerpt from "One Flu over the Cuckoo's Nest." Scientists debated creating a killer virus to study in the lab. In 2005, the Centers for Disease Control proposed deliberately combining a deadly bird flu virus with a very contagious human flu virus to understand whether and how it might cause a worldwide outbreak, or "pandemic." Scientists said the lab experiments would help them understand what might already be happening naturally. . . .

But other people thought such research was a terrible idea. What if these viruses escaped the lab by mistake? What if a government or terrorist organization wanted to use the viruses against their enemies?

In 2013, two research groups outside the United States went ahead and conducted their own experiments. One group, led by Ron Fouchier of Erasmus University in the Netherlands, showed that the highly lethal mixed up flu virus could infect and kill ferrets. A few months later, a Chinese group led by Chen H