Dead of Night — Randy Wayne White

It starts with a simple request: check up on the mysteriously reclusive biologist brother of an old friend. But what Doc Ford stumbles upon in the doctor's secluded island home is a nightmare. He has hanged himself--and his body is host to a rare strain of feeding, breathing parasites. It's not an accident. Neither is the fact that the flesh eaters are multiplying in the infested Florida waters. A biological catastrophe has arrived. And only Doc Ford can find out why, and stop it from spreading further...