Parasite

A decade in the future, humanity thrives in the absence of sickness and disease. We owe our good health to a humble parasite -- a genetically engineered tapeworm developed by the pioneering SymboGen Corporation. When implanted, the Intestinal Bodyguard worm protects us from illness, boosts our immune system -- even secretes designer drugs. It's been successful beyond the scientists' wildest dreams. Now, years on, almost every human being has a SymboGen tapeworm living within them. But these parasites are getting restless. They want their own lives . . . and will do anything to get them. Related books (by series) Parasitology   Parasite   Symbiont   Chimera Newsflesh   Feed   Deadline   Blackout Newsflesh Short Fiction (e-only novellas)   Apocalypse Scenario #683: The BoxCountdown   San Diego 2014: The Last Stand of the California Browncoats   How Green This Land, How Blue This Sea   The Day the Dead Came to Show and Tell   Please Do Not Taunt the Octopus