When I turned 16 or so, there was a scare about a brain eating amoeba in our lakes. The trigger was the temperature and, of course, pollution. I just stuck to the springs and oceans in the summer and never, ever had a problem. Your body has an amazing ability to fight off most infections. It can fight off this as well if it doesn't get overwhelmed. The hotter the temps, the more cooties are in the water and the better chance your immune system will be overwhelmed. Compromise that immune system at all, and it's even worse. Stay off the Florida beaches if you're sick, on drugs or otherwise compromised.