A typical mattress can house up to 10 million dust mites. A single gram of dust taken from a mattress usually contains more than 2,500 dust mites.
Dust mites are microscopic, eight-legged arthropods that feed on human skin scales, animal dander, pollen, fungi and bacteria. They do not bite and are not parasitic, but they can cause allergic reactions. They need temperatures above 75 degrees Fahrenheit to thrive, and they prefer humidity levels of 70 percent or greater. To control dust mites in a house, humidity should be reduced to less than 50 percent. Carpeting should be steam-cleaned or shampooed at least once a year, or it should be replaced with washable rugs. Bedding should be washed weekly with warm water. Regular, thorough vacuuming with a vacuum cleaner that has a high-efficiency filter can also help.