Univ. of Georgia

Human beings occasionally get diseases from animals, such as swine flu, rabies and anthrax. A new study finds that humans can also spread disease to wildlife, with grim results. A bacterium from our guts is now rampaging through coral reefs in the Caribbean.

Those reefs were already in slow decline, but they took a huge hit starting in 1996, when a disease called white pox appeared in the Florida Keys.