As a 12-year old boy fights for his life in Miami, the Florida Department of Health has issued a warning to anyone who might come in contact with warm freshwater.

Zachary Reyna is the second child in several weeks to suffer from the deadly parasite known as primary amoebic meningoencephalitis; the first was 12-year old Kali Hardig, an Arkansas girl. Hardig spent several weeks in intensive care after contracting the parasite at a water park but is now in rehab after receiving an experimental anti-amoeba drug. Now, Reyna’s parents hope the same drug will help him recover.

The Reyna family says Zachary was knee-boarding in shallow water with some friends on August 3; the next day, he slept the afternoon away. Because it was so out of the ordinary for him to rest that much, his parents took him to the emergency room, where he was diagnosed with the illness. He has since had brain surgery, and now his family waits to see if the medicine will work.

The Arkansas water park where Kali likely contracted the parasite has been shut down for the time being, because a previous case of the illness was reported there in 2010.

“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.

Florida officials say that high water temperatures and low levels are breeding grounds for the amoeba and that the best way to avoid it are to stay away from swimming in freshwater during those times. If it can’t be avoided, they say, use nose plugs to keep the water out. Symptoms include 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 CDC says. “After the start of symptoms, the disease progresses rapidly and usually causes death within one to 12 days.”

A similar infection caused Aimee Copeland to lose both hands, a leg and a foot last year after she cut herself while ziplining over a Georgia lake. Bacteria from the water got into her wound and spread rapidly, but doctors were able to save her life.