The single-celled organism behind the infections is usually found in warm bodies of freshwater, including lakes and rivers. Once a person is infected — an exceedingly rare occurrence usually resulting from swimming or diving in infected waters — the amoeba travels from the nose into the brain.

Once there, the organism can kick off a nasty brain condition called primary amebic meningoencephalitis (PAM). And yep, according to the CDC, PAM is “usually fatal.”

The good news: there have only been 34 infections reported in the US in the last ten years, according to CDC data.