Yeah. Worms are what I wanted to write as well…the Guinea worm (Dracunculus medinensis),sometimes also called medina worm, is one of these and was once really common. The Asclepius rod is possibly coming from it.

If your character has a backstory that brings him to southern Europe, Asia or Africa in these times it’s basically perfect.

Another disease to look up: Larva migrans cutanea