Recovering Brain-Eating Amoeba Victim Learns to Enjoy the Water Again Kali Hardig, 12, went swimming in a hospital pool, her doctor said.

Sept. 7, 2013 -- A 12-year-old Arkansas girl who is recovering after battling a rare infection caused by a brain-eating amoeba went swimming at a hospital pool on Friday, her rehabilitation physician said.

Kali Hardig was in critical condition after being diagnosed in July with primary amoebic meningoencephalitis -- an almost-always-fatal form of meningitis caused by the parasite Naegleria fowleri. She began to show signs of recovery in August, uttering her first words and taking her first steps since the harrowing diagnosis.

Read More About Kali's Recovery

Kali is thought to have contracted the brain-eating amoeba from a sandy bottomed lake at Willow Springs Water Park in Little Rock, Ark., according to the Arkansas Department of Health. The 85-year-old water park, which was linked to an earlier Naegleria infection in 2010, has since closed.

But while the 12-year-old continues to regain her strength in the hospital, her mother wanted her to feel comfortable in the water again, Esther Tompkins, Kali's rehab physician and a doctor of osteopathic medicine at Alabama Children's Hospital, told ABCNews.com.

"Her mom noticed that she was somewhat fearful of water, which is obviously where she got the ameoba from," Tompkins said. "Her mom wanted her to work through her fear of water and the perfect place to do that was the pool at the hospital. She always enjoyed swimming before she got sick and her mom would like to have her enjoy that again."

Kali took steps to conquer her fear of the water on Friday afternoon, spending an hour swimming at the hospital's pool alongside her mother and three therapists, Tompkins said.

The girl prepared for her swim by going into the hospital's pool room to feel the water and get acclimated with the pool's surroundings on Thursday, Tompkins said. She swam and played for more than an hour on Friday afternoon, and even swam underwater.

Kali has made such incredible strides in her recovery that she may be released from the hospital as soon as next month, Tompkins said.

"She's a go-getter and a hard worker," she said. "She just improves daily."

But while her infection may be gone, the 12-year-old still will need to continue to undergo occupational, physical and speech therapy following her release, Tompkins said.

"She's still a little slow in her speech, and her memory is a little slow but that's improving," she said. "She needs to wear braces to walk and she has a little problem with balance, which produces ataxia. It makes her gate kind of unsteady."

But Tompkins said Kali continues to work on strengthening and conditioning, and may even go back into the hospital's pool again for a swim.

Only two people in North America are known to have survived the rare infection, according to the U.S. Centers for Disease Control and Prevention.

"We want Kali to be #3!!!" reads a post on a Facebook page dedicated to the girl's recovery, where the Hardig family has been posting photos and regular updates on her condition.

In August, Zachary Reyna, 12, of LaBelle, Fla., was taken off life support after the water-borne paraside left him brain dead, according to a Facebook post by his family.

"Zac donated all his organs to others that were waiting on a miracle," reads the post on the Facebook page "Pray4Number4." "Through donating his organs, Zac is living on. His heart will be pumping for someone, his lungs will be taking breaths for someone and all his other organs will change the lives of many."

Naegleria fowleri thrives in warm, standing freshwater and the sediment of rivers and lakes. And while it's usually harmless, it can cause fatal brain swelling if inhaled through the nose.

Early symptoms of a Naegleria infection include a severe frontal headache, fever, nausea and vomiting, according to the CDC. But those can swiftly give way to a stiff neck, seizures, confusion and hallucinations as the amoeba makes its way up through the nasal cavity into the brain.

"After the start of symptoms, the disease progresses rapidly and usually causes death within about five days," the CDC's website reads. "People should seek medical care immediately whenever they develop a sudden onset of fever, headache, stiff neck and vomiting, particularly if they have been in warm freshwater recently."

ABC News' Katie Moisse contributed to this report.