By the Grace of the Gods 03 (Manga)

Office worker Ryoma Takebayashi had an unpleasant life and an unlikely death, but the gods of a parallel world reincarnate him as a boy with great magic abilities and all memories intact. After Ryoma registers with an Adventurers' Guild, his first challenge is protecting a town from an epidemic. Will his modern-day Earth knowledge and advanced slime skills be enough to halt a plague?!

Volume 3 of the By the Grace of the Gods manga series by Roy.