High water temperatures and low water levels are the ideal breeding ground for this rare but extremely deadly brain-eating amoeba. Health officials in Florida are now issuing a warning "to be wary when swimming, jumping or diving in fresh water" with these conditions, CNN's Elizabeth Cohen reports.
It's rare, but the amoeba can go up the nose and into the brain, causing parasitic meningitis.
12-year-old Zachary Reyna is battling the disease in Miami Children's Hospital after contracting it while knee boarding in fresh water near his home. On Facebook, his brother says Zachary had surgery to remove pressure from his brain.
Nearly everyone who gets this infection dies. In the past 50 years, only three people have survived.
Most recently, 12-year-old Kali Hardig, who's out of a coma and now in fair condition at Arkansas Children's Hospital. Doctors credit her amazing survival – in part – to an experimental anti-amoeba drug.
The Centers for Disease Control has sent the drug to Miami to treat Zachary, and just as friends and family had prayed Kali Hardig would be the third person to survive this horrible infection, Zachary's supporters hope he'll be next.