Naegleria fowleri is a one-celled organism that the U.S. Centers for Disease Control explains is “often called the 'brain-eating ameba' because it can infect the brain and destroy brain tissue." This happens when water containing the amoeba goes up the nose to the brain, causing an infection called primary amebic meningoencephalitis (PAM).

The deadly infection has been historically rare, but as climate change heats up waters and worsens flooding, research shows cases could become more common.