One thing I think a lot of you are missing that's important. YOU are the host, @LGAMMA1 mentioned how they are so small you need a good microscope to see them. Now, if that's true, are they not small enough to enter your pours?
How small must their eggs be?
The eggs, the parasite, it's using your body as it's host. 90% of them in your environment are "hatched" from your body. When you move several times and get rid of everything this quickly become obvious.