Dust Mites
Dust Mites are tiny bugs that live in beds and feed on dead skin cells people shed each day.
Think of it this way
A bread box sitting on a counter holds a loaf of bread. As the bread dries out, tiny flakes of crust fall to the bottom. Now picture very small bugs living inside that box, too small to see. They stay hidden in the crumbs at the bottom and eat the dry flakes.
Explaining dust mites by grade level
Tiny bugs live in your pillow. They are too small to see. They eat bits of skin that fall off your body. Washing your sheets in hot water kills them and keeps your bed clean.