Symptoms include mild headaches, muscle pain, fever, a persistent cough and sometimes vomiting and diarrhoea.

BBC: Legionnaires' Disease bacteria

The telltale signs of a problem are a fever and persistent pain that's disproportionate to the injury: Sometimes it's "the worst pain they've ever experienced, " he said.

CNN: Surviving a flesh-eating disease

That is not to deny that antitrust action is sometimes right even in high-tech industries: Microsoft's dominance became so large, and so persistent, that it deterred rivals from innovating.

ECONOMIST: Merger regulation