Nation Swimming in freshwater? Here’s what to know about the rare brain-eating Naegleria fowleri. July 16, 2022Ashley R. Williams, USA TODAYComments Off on Swimming in freshwater? Here’s what to know about the rare brain-eating Naegleria fowleri. Naegleria fowleri is the only species of Naegleria that infects humans and has a 97% fatality rate, according to the Centers for Disease Control.