BERLIN — More than 1,000 toads have puffed up and exploded in a Hamburg pond in recent weeks, and German scientists still have no explanation for what's causing the combustion, an official said Wednesday. Both the pond's water and body parts of the toads have been tested, but scientists have been unable to find a bacteria or virus that would cause the toads to swell up and pop, said Janne Kloepper, of the Hamburg-based Institute for Hygiene and the Environment. "It's absolutely strange," she said. "We have a really unique story here in Hamburg. This phenomenon really doesn't seem to...