Dust may contain tiny fibers shed from different kinds of fabric, as well as tiny particles of feathers, dander from pet dogs or cats, bacteria, food, plant and insect parts, and mold and fungus spores. It also contains many microscopic mites and their waste products. These waste products, not the mites themselves, are what cause allergic reactions. Dust mite waste contains a protein that is an allergen a substance that provokes an allergic immune reaction for many people. Throughout its life a single dust mite may produce as much as 200 times its body weight in waste.
Most dust mites die when exposed to low humidity levels or extreme temperatures.
But they leave their waste behind, which continues to cause allergic reactions. In a warm, humid house, dust mites can easily survive year round. Unless you live in Antarctica or in an extremely dry climate, there is probably no practical way to completely rid your home of dust mites. But you can take action to lessen their effects. Having dust mites doesn't mean that your house isn't clean.