Story highlights Sebastian DeLeon was treated with the antiparasitic drug miltefosine

Three other patients have died from Naegleria fowleri this year

(CNN) Sebastian DeLeon, 16, has survived a rare brain-eating amoeba, doctors at Florida Hospital for Children in Orlando said Tuesday.

"He's done tremendously well. He's walking, he's speaking, he went outside for the first time to get some fresh air -- he's ready to go home," Dr. Humberto Antonio Liriano, a critical care physician, told reporters.

It's remarkable because he is only the fourth person in the United States to survive an infection from this parasite, called Naegleria fowleri.

On vacation with his family in Orlando, DeLeon had a severe headache while they were at a theme park on August 7. The pain became so bad, Liriano explained, the teen "couldn't tolerate people touching him."

A search for local hospitals ensued and they fortuitously discovered Florida Hospital for Children, where they brought the teen. Later, they learned doctors there were uniquely knowledgeable about this amoeba -- they'd attended special seminars on the topic earlier this year.

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