Kali Hardig in critical condition in Arkansas
                                
                                
                                    (Newser) -
                                    Kali Hardig, 12, went swimming in a Little Rock, Ark., lake earlier this month—and, in a nightmare scenario, she's now battling a  brain-eating parasite . Naegleria fowleri is a microscopic amoeba that gets to the brain through the nose, typically infecting people who go swimming in freshwater,  CNN  reports....