I like introducing you periodically to some of the stranger and more dangerous germs out there. It’s a good reminder that nature isn’t just full of daisies and rainbows, and that the most lethal dangers we face are natural. This week’s news presents a terrific example. Meet Naegleria fowleri. Naegleria fowleri is an amoeba, a single celled parasite that lives in warm bodies of fresh water, like lakes and rivers. Its nickname is the brain-eating amoeba. Isn’t that nice? (My nic...