Peeps

Peeps, also published as Parasite Positive, is a 2005 novel by the American writer Scott Westerfeld. It is built on a parasite that makes its carriers cannibalistic and repels them from the things they once loved, and it follows Cal Thompson, who lives with the infection.

Cal is a college freshman in New York when he discovers that he has been infected and that he has passed the parasite on without knowing it. Most carriers become dangerous, and the small number who stay themselves are hunted across the city, so Cal works for an organisation that tracks down the people he infected and deals with them, while trying to find the source of the outbreak, a history that reaches back into the city's past.

Westerfeld alternates the story with short chapters about real parasites, which gives the novel a documentary counterweight to its horror plot and is the part of the book readers tend to remember. It was followed by a companion book, The Last Days, and it is aimed at older readers than his Uglies series.