Parasite

Parasite by Mira Grant takes place in a world where everyone lives with a tapeworm inside their body protecting them from illness.  Sally woke up after a car accident with no memory of her earlier life.  Sally's medical care was paid for by Symbogen, the company that engineered the tapeworms and her life is carefully monitored by them.  When people suddenly start blacking out and turning into sleepwalkers Sally and her boyfriend decide that they have to figure out what's going on.

While this was an interesting novel that readers who enjoy Mira Grant's style will enjoyed it suffered by telling too much instead of showing.  A huge portion of the book was taken with explanations of the "science" and it really dragged down the storytelling.  The action and horror were good but it took a long time for the story to get started.  I will not read the sequel without reading the reviews first.

Appropriateness:  Mira Grant's books fit in the "new adult" genre.  No excessive adult content but certainly written for older readers with a main character in their early 20's.  This is a great book for teen sci-fi fans.