Dust mites are microscopic arthropods, measuring only a quarter to a third of a millimeter, which makes them too small to be seen with the naked eye. Under the microscope, they appear as white bugs with eight legs, and they must be magnified several hundred times to be visible. The average size of a dust mite is between 0.2 and 0.3 millimeters, or 20 microns. In some cases, airborne particles containing dust mite allergens have been observed to range from 5 to 40 microns.
House dust mites are the most common asthma triggers and can cause an additional condition called atopic dermatitis, or eczema, which results in severe itching and redness. The two most common species of dust mites are Dermatophagoides farinae Hughes (American house dust mite) and Dermatophagoides pteronyssinus Trouessart (European house dust mite). A female mated house dust mite can live up to 70 days and lay up to 100 eggs in the last five weeks of life, with an average life cycle of 65 to 100 days. During this time, they produce around 2,000 fecal particles and an even larger amount of dust particles covered with partially digested enzymes.
Dust mites feed on skin scales from animals, including humans, as well as some types of mold. Their feces contain powerful digestive enzymes called peptidase 1 which can cause allergic reactions in humans. Allergy tests performed by a doctor can determine if respiratory or dermatological symptoms are caused by dust mites and if allergen immunotherapy is necessary. Epidemiological data has shown that the presence of house dust mites is associated with an increase in indoor air humidity.
The most effective way to prevent or minimize exposure to dust mites in our homes is thorough cleaning, the use of high-efficiency particulate air filters, and pest control. Other methods include using a dehumidifier and washing bedding with hot water (at least 130-140°F). It is also recommended to cover bed linen, mattresses and pillows with waterproof covers that prevent dust mites from settling on beds. House dust mites are globular in shape, light to creamy white in color, with hairs on the legs and body.
They contain approximately 75% water by weight and need to absorb water from water vapor from the air, so relative humidity is a critical factor for survival. Wash all blankets and bedding with hot water at a temperature of 130 to 140°F to kill dust mites once a week, and bedding that can't be washed can be kept cold overnight. Conventional pesticides should not be used to control house dust mites. Understanding the life cycle of house dust mites as well as environmental factors that influence their populations can be used to control them. After identifying a dust allergy, the allergist may recommend one or more treatments such as medications, allergy shots (subcutaneous immunotherapy), tablets (oral immunotherapy), or changes to personal household routine. In addition to being allergens, house dust mites can also be used as valid tests for solving forensic cases due to their presence, diversity, and wide distribution everywhere.
At this stage, an introductory practical taxonomic identification of the most common and important house dust mites is presented.
