Dust mites prefer to live in a temperature range of 25-30 °C (77°F) and a relative humidity of 75-80 percent. Dust mites prefer live in fabric and animal hair such as beds and couch and pillows. They spread very quickly. The research suggests that 10% of mattress weight is accounted for the weight of dust mites and their waste products. The mattress which is used for more than 6 months generally carry excess level of dust mites, much beyond the safety standard.
The main course for dust mites is dead skin, scurf and dandruff of animals, including human livings. In fact, when we sleep, billion pieces of our skin are sloughed off and become the delicious dish for those dust mites. Incredibly, just one gram of our scurf is enough to feed 1,000,000 dust mites for a week. Unsurprisingly, the research reports that every mattress that is used for more than 2 years might carry about 1,000,000,000,000 dust mites.
One female dust mite can lay up to 80-100 eggs throughout its lifetime. The lifespan of dust mites is only 1-2 months and there are 5 stages of growth in their life cycle. A newborn dust mite has only 6 legs. After sloughing off, they will contain 8 legs. After 1-2 months, these dust mites will die and their dead bodies cannot leave the mattress, thus accumulate inside it. This becomes the major risk factor which causes allergic in people.
Researches suggest that "dust mite" itself does not cause any harm to humans, but its excrement and dead body, which contain "guanine", do. Guanine unavoidably gets into the body through breathing. Over a long period of time, this guanine might cause allergy. The symptoms may include asthma, rhinitis, dizziness, coughing, sneezing and in some cases, it may even causes shock and death.
Washing bed sheet and pillow cases using room temperature water cannot kill dust mites, but it can remove dust mites' excrement and dead body. However, most of dust mites generally live inside the mattress and pillow, not just on their cover.
The appearance of dust mite's mouth does not allow it to bite anything, even food. It can only imbibe food. However, people who are allergic to dust mites feel itchy because of guanine and other wastes.
Both chemical and non-chemical spray may kill dust mites, but their dead bodies, as the main cause of allergy, still accumulate in our mattress. Therefore, only spraying our mattress with those chemicals can kill dust mites, but cannot remove any allergens. In addition, whenever we use the spray, its residues must be concerned.
Dust mites cannot be survived at the temperature greater than 60 °C (or 140 °F). As the heat from sunlight in Thailand is approximately 30-40 °C, it is ineffective to kill dust mites. However, exposing the mattress to sunlight can kill germs, bacteria, and also inactivate eggs of dust mites. When the pillows and mattress is exposed to sunlight, dust mites are able to migrate from the side that is directly exposed to the sun to another opposite site. Although sunlight is insufficient to kill dust mites, their breeding would be delayed.
Dust mites were originated 500 billion years ago and are still existed. Dust mites are very tiny and can be flown into the air, thus, it is almost impossible to totally remove them. The research suggested that health hazards are not directly due to the presence of dust mites themselves, but their wastes. Therefore, regularly cleaning our home, especially our mattress and couch, and try to minimize the possible habitat of dust mites (i.e. dolls, carpet) from our bed room, can protect us from being allergic.