if they are not dusted regularly, they could be affecting peoples allergies.
also, if kept too moist, they could derive a fungus.
Yep I have to agree with this,,
The Dr's office staff should be wiping down the leaves every week with a Mild soap w/ water( Like Lemon Joy in a mister teaspoon per quart) just spray on and wipe off,, that will also take care of some
tiny insects as well,,