Good examples, Marco, I'll comment more on them when I can find time.
Wyrms was a general-purpose word with a lot of meanings. Sometimes medieval people used "worms/wyrms" in the same way we use the word "germs"—to mean those "invisible" things that make people sick. Of course, they didn't know about germs yet, so they generally associated worms (the invisible make-you-sick kind) with demons or omens or "bad air".
Wyrms was a general-purpose word with a lot of meanings. Sometimes medieval people used "worms/wyrms" in the same way we use the word "germs"—to mean those "invisible" things that make people sick. Of course, they didn't know about germs yet, so they generally associated worms (the invisible make-you-sick kind) with demons or omens or "bad air".