"To understand that," Dombey said, "you have to go back twenty months. It was around then that a Chinese scientist named Li Chen defected to the United States, carrying a diskette record of China's most important and dangerous: new biological weapon in a decade. They call the stuff 'Wuhan-400' because it was developed at their RDNA labs outside of the city of Wuhan, and it was the four-hundredth viable strain of man-made microorganisms created at that research center."Wuhan-400 is a perfect weapon. It afflicts only human beings. No other living creature can carry it. And like syphilis, Wuhan-400 can't survive outside a living human body for longer than a minute, which means it can't permanently contaminate objects or entire places the way anthrax and other virulent microorganisms can. And when the host expires, the Wuhan-400 within him perishes a short while later, as soon as the temperature of the corpse drops below eighty-six degrees Fahrenheit. Do you see the advantage of all this?"