This summer, Naegleria fowleri is the new great white shark. A freshwater-dwelling amoeba that can invade the human nervous system and, on rare occasions, kill, N. fowleri (or, as they are more commonly known, "brain-eating amoebas") have apparently succeeded in making everybody a little more afraid to get in the water.
But is the fear justified?
Most of you can probably guess that the answer is, "No." But why, specifically? Julia Diebol at the Risk Science Blog does a nice job of clearly laying out why these amoeba are so attention-grabbing, and why they shouldn't keep you up at night.
Shorter version: Just being in amoeba-infested waters doesn't mean you'll get one up your nose. Or, at least, it doesn't mean that you'll die. The amoebas have only killed 129 Americans since 1937. That's more than I'd previously thought, but not remotely enough to justify a panic. Especially given that the risk of infection doesn't seem to be increasing.
Granted, there's a lot we don't know about N. fowleri. Key question: Why can hundreds of people swim safely in lake water that leads to amoeba infestation and death for one person? Nobody knows yet what factors make some people susceptible and others, apparently, not. But we do know this: On your list of things to worry about, brain-eating amoebas should be near the bottom.
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.