The Walking Dead virus, which causes the zombie outbreak in the series, originated in a French laboratory with the Primrose and Violet teams
. The outbreak was not intentional but was caused by a group's attack on the facility
. The virus was later revealed to have spread from la Biomédicine DDMI in France and was discovered by the Center for Disease Control on April 15, 2010
. The disease quickly spread, leading to the zombie apocalypse in the series. Robert Kirkman, the creator of The Walking Dead, deliberately chose not to reveal the zombie origins in his comic series and has consistently shied away from providing a detailed explanation
. He believes that leaving the cause of the zombie outbreak unresolved adds to the mystery and keeps the story grounded
. The focus of The Walking Dead has always been on human nature and moral dilemmas, rather than the supernatural or scientific aspects of the zombie outbreak
