Medical menace (now vying with lawyers-in-legal-combat for the top spot in the mystery/thriller hit parade) always plays well on audio. The Eleventh Plague, a doozy of a disaster drama, by John Baldwin and John S. Marr, epidemiologist and expert on emerging infections, is truly menacing. A brilliant virologist turned bio terrorist is playing games and having fun. First, it's fun at the expense of only a few lives, then the numbers jump to possible plague proportions plagues that reenact the ten horrors visited on the Egyptians in the book of Exodus. The only man who can spot and stop this weird serial killer is himself suspected by the FBI and that doesn't help the cause. The good thing, if you're a medical mystery maven, is that the perp may live to try again, and that means another hair-raising audio episode of disease-driven drama. With it, I hope, will come another performance by reader John Shea. Reviewed by Sukey Howard.