PUBLIC HEALTH: Deaths Among Heroin Users Present a Puzzle.

More than 30 heroin users in Scotland and Ireland have succumbed to a mysterious malady in the past 6 weeks, leading health officials to suspect anthrax, the notorious biological warfare agent. Now, analyses by microbe hunters on both sides of the Atlantic offer a somewhat reassuring conclusion: Anthrax did not kill the heroin users. It's unclear what did, but a new suspect has emerged.