Description: It's a Zombie apocalypse manga set in a highschool with this dude who tries to save a girl at the expense of his friend. (And before you say anything, it's not Highschool of the Dead)
Genres: Action, Shounen etc.
Character's Gender and Appearance: MC was a skinny dude, but I think both he and his best friend were boxers. He had darker hair.
Scene: MC watches people get bitten. MC ties up girl (his love interest) with rope. Zombies go back and for from psychotic murderous dead people to badly injured living people, randomly and repeatedly, with seemingly no memory of what they did as zombies.
Writer: No clue.
Other Clues: Zombie virus was compared to rabies. Edit: And it's long enough and popular enough to be serialized in tankoubon form.

Thanks in advance.