Lunacy was believed to be an affliction where the moon's face drove the weak-minded into fits of madness. Behavior associated with menstrual cycles also led to the idea of 'hysteria' or madness caused by internal organs. A village could be normal every time the adventurers pass through, but rumors might persist: a bare dozen travelers per year disappear on the road through this village.
Vibrio Vulnificus (and other Vibrio infections) are spread by the bites of reptiles such as alligators and would be attributed to poison or venom. The wound site turns black, green, or purple and swells. Skin near the wound develops pustules and boils, and the victim runs a high fever. Without treatment the limb might fall off -- but the time frame is long enough to spur a "save the fighter's arm!" side quest. Kobolds, dragonkin, drakes, and other reptiles could spread disease instead of generic 'poison damage' if they live somewhere particularly septic like a swamp. Go to Comment
In a long-lost age, a party of adventurers are frozen into stone by the stare of some gorgon-like creature. An unscrupulous rogue, coming across the frozen party several centuries later, decides to haul off two of the statues to decorate his den. Upon his death, an artisan friend of his claims a statue and sells it to a rich merchant, passing it off as his own work. Years later, the merchant gilds the statue in bronze and re-sells it at a much higher price. After passing through the art markets for many decades, the statue ends up in the hallways of a mage academy. Imagine the chaos and confusion when a young mage's spell happens to break the curse of stone, returning the adventurer to life several centuries after his petrification! Is he interrogated by historians? Driven mad by the change of times? Or does he set off on a quest to find and liberate his other frozen party-members?