Whereas many kinds of mites infest mammals and birds, just two kinds are solely dependent upon people for their sustenance and survival. One is the human scabies mite and the other is the follicle mite. These invade our skin and cannot live without us. Virtually all of the other kinds of mites (except for some ticks) that affect the health of people do so by accident. Many blood feed, but prefer to attack other kinds of animals. Indeed, although they may feed – or try to feed - upon a person, most mites will fail to thrive without their preferred mammal or avian hosts.
Sarcoptes scabei - life cycle of the human scabies mite
from CDC Public Health Image Library ID# 3416