There was a lawsuit a few years back, where a child had a small parasitic ameba entered through either the nose, or ear while swimming in the lake. After that the waterways where closed to swimming, because it did cause a serious if not fatal infection.
That's also why River County is closed...this ameba lives in all lakes in Florida I believe.
Habitat - Ameba live in most types of fresh water sources such as ponds, lakes, and streams. Plus sometimes they can live in moist soil. They can also live in dry condition by with drawing into a thick walled crystal, which it forms around its self.
Life cycle - Amebas reproduce when they are full grown. They do this by having their nucleus and protoplasm divide in to two daughter cells. The ameba can also live as long a two hours without a nucleus.
If anyone else remembers anything about this case please post...and correct me if I have the wrong information.