Neogeo,
No need to be scared. People are scared because of what they do not know.Quoted in that article :

While exceedingly rare, Naegleria fowleri infections are almost always fatal. Only one person out of 128 infected in the United States between 1962 and 2012 has survived, according to the U.S. Centers for Disease Control and Prevention.

Let"s do the math : If 128 persons got infected in 50 years and 100 billion persons went swimming in that period. Then your chances of getting infected are = 128/100,000,000,000. Or 1.28E-9 that is what my calculator says. I do not know exactly what that means but I think you could have won the CA. lottery several thousand times before you got a ameoba headache. Or you would have been killed in a car wreck and killed several thousands of times. Or, a lightening bolt would have hit you several thousand times. Before we call the doctors for you.
Me I aint scared because 1.28E-9 is a very very slim chance.
Besides the numbers, those bugs were confined to the tropics before this globe warmed up dew to the industrial revolution. So lets blame future infections on people unwillingness to stop driveing. And I dout those bugs like this hot old desert.
Digging for facts is better mental exercise than jumping to conclusions. I do not know who said that but, I am sure it is true.
Glad 2 help !
Once again my spell checker has stopped. ?