( CNN ) -- Doctors say there may be a glimmer of hope for a 12-year-old girl in Arkansas who is infected with a rare but deadly brain-eating parasite . Not a single person is known to have survived such an infection in the past decade , but Kali Hardig is hanging on in critical condition , according to doctors at Arkansas Children 's Hospital . Hardig 's mother took her to the hospital nine days ago . Hardig had a fever and a headache , but something else did n't seem right . Doctors checked her spinal fluid , and that 's where they found a microscopic amoeba called Naegleria fowleri . The amoeba enters the body through the nose and travels to the brain . It 's usually found in people who have been swimming in warm , fresh water . You can not be infected with the organism by drinking contaminated water , the CDC says . `` This infection is one of the most severe infections that we know of , '' Dr. Dirk Haselow of the Arkansas Department of Health told CNN affiliate WMC . `` Ninety-nine percent of people who get it die . '' Why 'nightmare bacteria ' on the rise . Dr. Sanjiv Pasala , one of Hardig 's attending physicians , says they immediately started treating Hardig with an anti-fungal medicine , antibiotics and a new experimental anti-amoeba drug doctors got directly from the CDC . They have also reduced the girl 's temperature to 93 degrees . Doctors have used that technique in some brain injury cases as a way to preserve undamaged brain tissue . Today , doctors checked the girl 's cerebral spinal fluid and could not find any presence of the amoeba . Pasala said that while other cases have not met with such favorable results , what may have made a real difference is that the girl 's mother got her to the hospital so quickly . Willow Springs Water Park in Little Rock is the most likely source of Hardig 's infection , according to a news release from the Arkansas Department of Health . Another case of the same parasite , also called primary amoebic meningoencephalitis , was reported in 2010 and was possibly linked to Willow Springs . `` Based on the occurrence of two cases of this rare infection in association with the same body of water and the unique features of the park , the ADH has asked the owner of Willow Springs to voluntarily close the water park to ensure the health and safety of the public , '' the news release said . What 's in your pool water ? The first symptoms of primary amoebic meningoencephalitis appear one to seven days after infection , including headache , fever , nausea , vomiting and a stiff neck , according to the CDC . `` Later symptoms include confusion , lack of attention to people and surroundings , loss of balance , seizures and hallucinations , '' the government agency 's website states . `` After the start of symptoms , the disease progresses rapidly and usually causes death within one to 12 days . '' Getting this amoeba is extremely rare . Between 2001 and 2010 , there were 32 reported cases in the United States , the CDC says . Most of the cases occurred in the Southeast . Here are some tips from the CDC to help lower your risk of infection : . • Avoid swimming in freshwater when the water temperature is high and the water level is low . • Hold your nose shut or use nose clips . • Avoid stirring up the sediment while wading in shallow , warm freshwater areas . • If you are irrigating , flushing or rinsing your sinuses ( for example , by using a neti pot ) , use water that has been distilled or sterilized . Flesh-eating bacteria survivor goes home . Doctors say it is still too early to know whether Hardig can survive or to know how much of an impact the amoeba has had on the girl 's brain .
Kali Hardig , 12 , is in critical condition at Arkansas Children 's Hospital . Amoeba causes fatal brain infection , according to the CDC . Parasite generally found in people who swim in warm , fresh water .