I remember hearing about these kinds of parasites on NPR a couple of years ago, ones that infect mice so they don't flee from predators and thus get eaten easily(the parasite then spreads through the predator). T. Gondii is featured on p. 39 of this book.
It's a great topic for a kids' book, because it's powerful and interesting science, but unlikely to be textbook science material and it's not one of the perennial topics like dinosaurs. Using the current mania for zombies was a good move by Rebecca Johnson to package the topic.
Bibliography and source notes are very good!
The thing that pushes this beyond the normal shock value is that every featured parasite is accompanied by "The Science Behind the Story" where Johnson discusses the work of specific scientists who have studied each parasite. I'll have to send a copy to Nancy's dad, Dick Heckmann, who is a parasitologist at Brigham Young!