Dust mites

Dust mites are members of the Phylum Arthropoda, Group Arachnida and Order Acarina, Mites are not spiders or insects but a group of their own closely related to ticks. Dust mites live in the fine layer of minute dust particles that continually settles on household items. They are found almost world wide but their numbers are considerably reduced at high altitudes and dry climates. House dust mites have been known to be associated with allergies since the 1960's and have become a focus over the years for their involvement with respiratory ailments. They do not bite or sting but harbour strong allergens in their bodies as well as in their secretions, excreta and shed skins. Constant contact with these allergens can trigger respiratory and dermatological complaints in some humans. Dust mites favour homes with high humidity levels and constant warm temperatures, and under these conditions mite populations explode, although there are some seasonal fluctuations. The mites are known to concentrate in high traffic areas in homes and on certain furniture items, especially beds, upholstered lounges, chairs, and in carpets with long fibres. They are attracted to these areas for food, and they feed on shed human skin scales and secretions, house dust, fungal spores, pollen grains, plant fibres, and insect scales. Dust mites dislike strong light and will take harbourage in the seams, ledges, and framework of furniture when exposed. Due to their light weight, dust mites can become airborne during activities such as bed making, and in this way can be distributed throughout the room or house.

Adult mites are described as white to a light tan in colour; they are difficult to see with the naked eye, as they measure only 0.5mm in length, and the developmental stages are smaller. The body of the mite is oval shaped and covered with fine striations. There are five stages in the life cycle of a dust mite; from the egg, the larvae stage, then two nymphal stages, and finally the adult. The whole life cycle from egg to adult takes approximately one month to complete, mature female mites can lay from 1-2 eggs per day. Adult mites can live up to two months but this is dependent on the levels of humidity and temperature of their surrounding environment.