The Naegleria fowleri amoeba can cause a rare but fatal brain infection that progresses quickly and can’t be cured. And it has been found in several recreational locations in the U.S., with the number of cases likely to increase as global temperatures rise.Unwelcome inhabitantScientists tested 185 water samples from 40 recreational waterways across five National Park Service sites. N. fowleri was found in 34% of the samples, according to a study…