Story highlights

NEW: Kali, infected with amoeba, is making progress

Florida Department of Health issues warning about amoeba in warm freshwater

Family says Zachary Reyna is receiving same drugs as Kali Hardig

Arkansas girl is in rehab in fair condition, the hospital says

(CNN) —  

While 12-year-old Zachary Reyna fights for his life against a brain-eating parasite, the Florida Department of Health has issued a warning for swimmers.

High water temperatures and low water levels provide the perfect breeding ground for this rare amoeba, called Naegleria fowleri, officials said. They warned the public “to be wary when swimming, jumping or diving in freshwater” with these conditions.

Reyna’s family told WBBH that Reyna was kneeboarding with friends in a water-filled ditch by his house on August 3. He slept the entire next day.

Reyna is an active seventh grader, his family said, so sleeping that much was unusual. His mother took him to the hospital immediately. He had brain surgery, and doctors diagnosed him with primary amoebic meningoencephalitis, according to WBBH. The family said he is currently in the intensive care unit at the Miami Children’s Hospital.

The CDC says it has been in touch with the patient’s doctors and has released the same experimental anti-amoeba drug used to treat 12-year-old Kali Hardig in Arkansas. Reyna’s family told WBBH he is also being treated with an antifungal medicine and antibiotics.

Kali was infected with the same parasite a couple of weeks ago and was at Arkansas Children’s Hospital in Little Rock.

The cases are nearly always deadly, but Kali’s condition is giving the Reyna family some hope.

“We continue to be amazed by Kali’s progress,” her family said in a statement Thursday. “Today she’s able to sit up on her own, write some words on a white board and stand with assistance for very brief stretches. She’s even able to throw and catch a ball with her therapists. We are grateful for the continued prayers from Kali’s supporters, which no doubt drive her recovery.”

Her attending physician, Dr. Vikki Stefans at Arkansas Children’s Hospital’s Progressive Rehab Unit, said in a statement Thursday: “Kali’s progress is definitely a credit to her wonderful family and support system,” Stefans said. “There is no longer a question of whether she’ll survive and do well, but just how well.”

Zachary’s family is hoping he becomes survivor No. 4.

“He’s strong,” his brother, Brandon Villarreal, told WBBH. “He’s really, really strong.”

Getting this parasite is extremely rare; between 2001 and 2010 there were only 32 reported cases in the United States, according to the CDC. Most of the cases are in the Southeast.

Naegleria fowleri is found in hot springs and warm, fresh water, most often in the southeastern United States. The amoeba enters the body through the nose and travels to the brain. There is no danger of infection from 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 about Hardig’s case. “Ninety-nine percent of people who get it die.”

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“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.

Several weeks ago, doctors checked the girl’s cerebral spinal fluid and could not find any presence of the amoeba.

Willow Springs Water Park in Little Rock is the most likely source of Hardig’s infection, the Arkansas Department of Health says. Another case of the same parasite was reported in 2010 and was possibly linked to Willow Springs, a three-acre sand-bottom, spring-fed lake.

“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 health department said.

Willow Springs’ website says its water is pH-balanced, chemically treated, chlorinated and routinely monitored by the health department.

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.”

Here are some tips from the CDC to help lower the risk of infection:

• Avoid swimming in fresh water 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.

CNN’s John Bonifield and Caleb Hellerman contributed to this report.