reincarnated into

Leon is thrusted into another world where There was a war where they used an atomic bomb causing some areas to become a biohazard so the government issued hazard masks. They also had purification centers but most of the country couldn't have them because it was too expensive. So to prevent people dying they were breeding poisonous plants to see if they could neutralize the poison so it will be safe to eat but the radiation got to hot exploding the facility. The seeds of the plant they created were scattered along the land. If you touch the the flower pollen will come out causing humans to become zombies. The facility also animals where the radiation was causing them to be mutated with the poisonous plants and the radiation. Also causing the four types of zombies,seekers,mimics,listeners, and humanoid. How it spread-larva of zombies leach on humans while they were fleeing the radiation and zombies but can't be unattached or the human would bleed out if they try. Larva state also sucks the blood out of the human once it drains the blood the host either dies or become a humanoid zombie.