Dawn by Ueda Shinshu is only two volumes long for now, book 2 was released in August 2004; the series is still being published in Zero-Sum, Issaisha (this magazine has so many great manga!). We can thus expect more tankoubon to come out.
Dawn~Tsumetai Te, or Dawn~Chilly Hands in English could be a shounen manga, but since it's published in the same magazine as Loveless, Saiyuki Reload or Weiss Side B, well it can only be a shoujo manga right? But it doesn't look like it, it can be very dark and is basically about disease and features monsters (there are a few little gore scenes).
Nagasawa Takashi is a normal teenager who attends high school, has a crush on a girl and spends his time with close friends. He's often alone at home, his parents working till late or going abroad. He's a member of the biology club, and when he gets bitten by a mouse, he freaks off and tells other people in the club about "pesuto", the Black Death. No one really takes seriously his story. But then coming back home late at night after a hard day at the club, he witnesses a car accident. He goes to see if he can help, when a strange creature attacks him and bites his arm. To get rid of it, Takashi crushes the ugly rodent-like creature on a tree trunk. He's at once afraid the beast was carrying a disease. An ambulance arrives and he's taken in charge by a mysterious doctor who doesn't really conforts him. After falling unconcious, he's bought to the hospital, where he'll stay for some time.
Finally back to school, Takashi is welcome by his friends. They talk about what happened during his absence: Takashi realizes he can't remember much of his sojourn at the hospital, probably because of his medecine, and he learns about horrible crimes in their area, corpses were found their head missing.
Takashi's nightmares and memory loss disturb him until the day when he's attacked by a homeless person (more or less a zombie). He feels something overwhelming him, hears a voice calling, "the voice of appetite": he suddenly jumps toward his aggressor...