The book Peeps by Scott Westerfeld is a science fiction novel. This book was published in 2005.Scott has also written the famous series The Uglies, and So Yesterday.
Cal Thompson is a carrier of a parasite that causes vampirism (parasite-positives also known as peeps) and must hunt down all of his ex-girlfriends that he has infected. Cal works for the Night watch in New York/ Manhattan , a group that catches and put the Peeps they have caught in intensive care , to make them more human. He also has the parasite, but it's different then the others. He does not thirst for blood or any human flesh.He is obsessed with Girls! He's called a Carrier. He can't even look at them without wanting them...He wasn't always a carrier. When he moved to New York to go to college he met Morgan, also a carrier and she gave him the parasite. He try to find her so he can destroy her so she won't be able to spread it anymore , and during his search he met Lace, a 24 year old girl that lives in the same apartment room as Morgan once did.
Cal and Lace gang up together and try to stop the parasite together because when Cal accidentally told her about it she wanted to help and she wouldn't take no for an answer.
They looked all over town for Morgan and when Lace told Cal that she found out where she lived they went to investigate and Cal saw that there were men there and Morgan was going to turn them too! He was so scared that he jolted out of there and Morgan came after him after her red eyed cat gave her his scent (red eyed cats are vampires too) and he runs all the way back to his apartment in Manhattan and Lace met him there.In the end Lace gets turned into a Peep when they find out that cats can get the parasite too and transmit it to people....her and Cal fall in love and are still on the look out for peeps.