Which means a special edition of 40k trivia:

Zombie Plague/Curse of Unbelief

The Zombie Plague, also called the Curse of Unbelief, is a deadly viral infection that was spawned by the Forces of Chaos and led to the creation of hordes of infectious, undead zombies that threatened billions of people on many Imperial worlds near the Eye of Terror in the Segmentum Obscurus. The first recorded incidence of the Zombie Plague in the 41st Millennium came in 757.M41 on the world of Hydra Minoris. A quarantine was imposed by the Imperial Navy, trapping 23 billion uninfected people alongside a rising tide of hungry and mindless undead.