Surely this isn't respiratory therapy related, although interesting nonetheless -- and medical, or sort of. Yet ancient societies recognized dental carries and many believed it to be caused by worms, perhaps because they noticed the canals in rotten teeth.
The following Babylonian tests shows how the Babylonians believed diseases were caused by gods or evil spirits, although they were aware of the naturalistic process:
After Anu (had created heaven),
Heaven had created (the earth)
The earth had created the rivers,
The rivers had created the canals,
The canals had created teh marsh,
(And) the marsh had created the worm -
The worm went, weeping, before Shamash,
His tears flowing before Ea:
"Wht will thou give for my food?
What will thou give to me for my sucking?"
"I shal give thee the ripe fig
(and) the apricot."
"Of wht use are they to me, the ripe fig
and the apricot?
Lift me up and among the teeth
And the gums cause me to dwell!
The blood of the tooth I will suck,
And the gum I will gnaw
Source: Ancient Near Eastern Texts, edited by james B. Pritchard, Princeton, Princeton University Press, 1969, pages 100-1