These invisible invaders are getting some peace of “mind” on your vacation. Often associated with big skies and purple mountains majesty, the US National Parks are increasingly becoming a cesspool for an insidious scourge — brain-eating amoebas. Researchers with the US Geological Survey and Montana State University found the parasitic interloper at thermal zones in three major National Parks: Lake Mead National Recreation Area, Grand Teton National Park, and Yellowstone National Park, ABC Utah