A rare “brain-eating amoeba” has been found in recreational waters at several western national parks, including Lake Mead , Grand Teton and Yellowstone. Researchers discovered Naegleria fowleri , which can cause a fatal brain infection, after surveying 40 thermally impacted recreational waters in five national parks and recreation areas in the western U.S. For the study, published by the U.S. Geological Survey and its partner agencies , 185 samples were taken from Yellowstone National Park, Grand Teton National Park, Olympic National Park, Newberry National Volcanic Monument and Lake Mead National Recreation Area. Scientists found the rare amoeba in about one-third of the samples, specifically from those taken from Lake Mead, Grand Teton and Yellowstone, according to the study. Naegleria fowleri is a one-celled organism that thrives in warm freshwater lakes, rivers and hot springs.…