Kamiyadori

From Tokyopop: Girard and ViVi are special government agents known as "Right Arms" whose job is to seek and destroy people who have become "infected." In this world, a weird virus that turns people into monsters has run rampant and the only way humanity can survive is to keep tight control over those who are infected. If the virus's symptoms appear, the person must be disposed of. It's a tough world where women and children must sometimes be killed to prevent the spread of the virus.