House dust mites burrow cheerfully into our clothing, pillowcases, carpets, mats and furniture, and feed on human dead skin cells by breaking them into small particles for ingestion. Dust mites are most common in asthma allergens, and some people have a simple dust allergy, but others have an additional condition called atopic dermatitis, often stated to as eczema by reacting to mites with hideous itching and redness. The most common type of dust mites are Dermatophagoides farinae Hughes (American house dust mite) and Dermatophagoides pteronyssinus Trouessart (European house dust mite) of family Pyroglyphidae (Acari), which have been associated with dermatological and respiratory allergies in humans such as eczema and asthma. A typical house dust mite measures 0.2–0.3 mm and the body of mite has a striated cuticle. A mated female house dust mite can live up to 70 days and lays 60–100 eggs in the last 5 weeks of life, and an average life cycle is 65–100 days. In a 10-week life span, dust mite produces about 2000 fecal particles and an even larger number of partially digested enzyme-covered dust particles. They feed on skin flakes from animals, including humans and on some mold. Notably, mite’s gut contains potent digestive enzymes peptidase 1 that persist in their feces and are major inducers of allergic reactions, but its exoskeleton can also contribute this. Allergy testing by a physician can determine respiratory or dermatological symptoms to undergo allergen immunotherapy, by exposing to dust mite extracts for “training” immune system not to overreact. The epidemiologic data on the occurrence of house dust mites convincingly associates with an increased indoor air humidity by increased occurrence of mites. The most effective way to prevent or minimize exposure to dust mites in our homes is thorough cleaning, use of high-efficiency particulate air filters and pest management. There are a number of things that can be done to get rid of dust mites, for instance, using a dehumidifier and washing bedding in hot water. Additionally, it is a noble practice to encase bedding, mattress and pillows in impermeable covers that prevent dust mites from taking up residence in beds. Owing to their everywhere presence, diversity, and wide distribution, mite species can be used as valid and reliable pieces of evidence for resolving of forensic cases.
- dust mite
The dust mites usually refer to those species of the mite family Pyroglyphidae that are known to commonly occur widely, although sometimes regionally, in the dust of human dwellings. Dust mites sometimes called dirt mites or bed mites are microscopic creatures, measuring only about one-quarter to one-third of a millimeter (250–300 microns) in length; females weigh about 5.8 μg, while males are approximately half of this weight as 3.5 μg. Nearly 72–74% of their total weight is water and they have translucent bodies with a striated cuticle. They are not insects but arthropods like spiders and ticks having eight legs, no eyes and antennae, and bear mouthpart set in front of the body . Dust mites can live in mattresses, bedding, upholstered furniture, carpets, curtains and other places in homes.
Each adult person sheds about one and a half grams of skin every day. This is enough to feed one million dust mites. Dust mites are microscopic creatures that can live in bedding and carpets, and feed on this skin. They feed on flakes of dead skin or skin cells and scales commonly called dander that are shed by people and pets. They like to live indoors, where they can get plenty of food like mold spores and dead skin cells from people and pets. They cannot survive in colder and drier places, however in a warm and humid house, dust mites can survive all the year around. Dust mites thrive in temperatures of 68–77°F (20–25°C) and they also like humidity levels of 70–80% .
These tiny individuals (Figure 1) are a big source of allergens and can worsen allergies and asthma. An allergen is a substance that causes an allergic reaction. Both the body parts and the waste of dust mites are allergens for many people. Most dust mites die in low humidity level (when the humidity falls below 50%) or extreme temperature, but they leave their dead bodies and waste behind to cause allergic reactions .
The house dust mite species of family Pyroglyphidae, commonly occurring in dust of human dwellings, belong to six genera, the so-called
|1||Commonly in the United States, not the United Kingdom|
|2||Europe, North America|
|4||Spain, Singapore, tropical regions|
|5||Commonly all over Europe|
|8||Humid geographic areas all over the world|
|10||United States, Canada, Europe, Asia, Middle East, parts of Australia, South Africa|
|12||United States, Canada, Europe, Asia, Middle East, parts of Australia, South Africa|
|14||Brazil, France, Singapore|
Related species of
Mites of family Tarsonemidae have modified legs IV (reduced, enlarged with a single tarsal claw on male, setiform on female); body with series of overlapping plates; and gnathosoma cone-like, enclosing minute palps and chelicerae. When mites are not as mentioned above, they may be with striated cuticle (family Pyroglyphidae), otherwise with smooth or papular cuticle, long serrated dorsal setae, and legs with long slim tarsi (family Glycyphagidae). Setae sci and sce are about the same length, and tegmen present in genus
An accurate taxonomic documentation of house dust mites is very vital, simply not from a biological standpoint but about the significances of their corresponding allergenic properties as well. Numerous works on immunochemical have exposed variances among the two products hard to differentiate sibling species [6, 7, 8, 9, 10, 11, 12, 13]. An introductory practical taxonomic identification for the most common and important house dust mites is presented at this stage. The main species, identified as
Many aspects on the biology of house dust mites are not understood; therefore, a greater understanding of their biology may reveal new strategies for controlling of mites and their allergens in homes.
2. Family Pyroglyphidae Cunliffe 1958 acarofauna
Pyroglyphidae belongs to the order Astigmata of the subclass Acari (also known as Acarina). The order Astigmata is differentiated from other orders of Acari by the lack of stigmata on idiosoma. This order is furthermore categorized into two suborders, the Acaridia that includes free-living mites and the Psoroptidia which comprises mites parasitic in nature. The former suborder is divided into many families, including the Pyroglyphidae, to which house dust mites belong. Pyroglyphidae are minute mites (full grown adults 170–500 μm in length), cuticle excellently or crudely wrinkle, tarsi termination in a circular pulvillus and a minute claw, anus ventral in position, vestigial genital structures present in both sexual category, vulva of female reverse Y or V fashioned, oil glands existing and exposed among L2 and L3, and vertical setae lacking .
Pyroglyphidae is a family of nonparasitic mites, wherein a great variety of species has been observed. It includes the house dust mites that live in human dwellings, many species that live in the burrows of other animals, and some are pests of dried products stored in humid conditions. The family Pyroglyphidae contains mainly species of astigmatid mites that live in the nests of birds and mammals, where they feed on the epidermal detritus (skin, feathers) left by the host, and occurs worldwide .
Among the genera of the family Pyroglyphidae, the most outstanding are
The presence of house dust mites can be confirmed microscopically, which requires collecting samples from mattresses, couches, or carpets. Also, in general practice, it takes at least a 10X magnification to be able to correctly identify them. A modified Berlese funnel is commonly used for extraction of mites from stored grain and has also been successfully used for extraction of
Dust mites are most closely related to spiders and ticks. These mites are about 25–30 millimeters in size and cannot be seen without magnification. The translucent body of a house dust mite is 300–400 μm in length and only visible under a microscope. They have eight hairy legs, a mouth-like appendage in front of the body, a tough shell and no eyes or antennae. The lifetime stages of the dust mites are eggs, larvae, protonymphs, deutonymphs, tritonymphs, and adult males and females. The duration of life cycle is dependent on temperature while relative humidity (RH) is beyond 60%. At 23°C, life cycle proceeds 36 and 34 days for
The female lays eggs singly or in small groups. The adult mated female can lay 40–80 eggs in its lifetime. When the egg hatches, a six-legged larva emerges. There are two nymphal stages that feed and molt before an eight-legged adult is developed. Transition from egg to adult takes about 3–4 weeks. The duration of the cycle is usually 1 month but is dependent on the climate, however 25°C and 75% relative humidity are ideal. An adult house dust mite can live for 1–3 months under favorable conditions. Normally, adult dust mites live for about a month and female dust mites live for about 8–10 weeks. It is estimated that the house dust mite can produce 20 fecal pellets/day that range from 20 to 50 μm. House dust mites are ~75% water by weight and therefore need to absorb water from the water vapor in the air, making relative humidity a critical factor for survival.
The population of
The house dust mites
An understanding of the life cycle of house dust mites, as well as environmental factors influencing mite populations, can be exploited in mite control. Experiments have been carried out to observe the influences of specific relative humidity maintained at 20°C on population dynamics of mixed and single species of
Mites are complex organisms, which produce thousands of different proteins and other macromolecules. Allergens from dust mites are connected to body secretions (chitinase), fecal material (enzymes) and body anatomy (muscle tropomyosin). Twenty diverse sets of mite allergens have been categorized. The incidence of reactivity to the majority of these allergens between patients sensitive to dust mites is beyond 50%. Sensitivity to allergens differs equally within and between persons. Generally, the prevalence of sensitivity to house dust mites is about 27.5% in the few populations. Allergens from one species may be species specific, or they may cross-react with allergens from another mite species. Most patients with mite sensitivities are allergic to multiple allergens of a species and to multiple mite species.
Allergies to dust mites are associated with allergic rhinitis and asthma. Systemic anaphylaxis may take place after eating of unheated or heated mite-polluted diets. This problem can be more widespread in subtropical and tropical states than earlier documented. The greatly common signs resulting after the consumption of mite-polluted flour are breathlessness, wheezing, angioedema and rhinorrhea, and these start in the middle of 10 and 240 minutes later after eating of contaminated foods .
3. Dust mite habitat
House dust mites primarily feed on organic detritus such as flakes of shed skin. Other nutrients are provided by animal dander, pollen, bacteria and mold. House dust mites reproduce and survive the greatest in soft stuffs (like carpets with lengthy pile, bedclothes and plush toys) that contain a big source of their diet source. The unchanging environmental circumstances are best provided inside homes. Internal domestic humidity is very vital, when moisture is less than 50%; house dust mites are incapable to sustain their water balance and become more vulnerable to desiccation. The house dust mites select diet which has been pre-decomposed by fungi that decrease fat content of skin cells. The fungi in turn usage house dust mite skin cells and feces as nitrogen source, which form a minute ecosystem in their environment .
The maximum vital limiting cause for house dust mite population densities is air humidity. House dust mite osmoregulation is through cuticle and for that purpose, they need a great ambient air humidity to avoid extreme water loss. Additionally, supracoxal glands take up ambient water vapor actively and protonymph stage in the life cycle is desiccation resistant. Greater house dust mite population densities are created when indoor absolute air humidity is beyond 7 g/kg (45% relative humidity at 20°C). As a result, aeration by air-conditioning structures is being established as a resource of mite control. In an integrated approach, a number of other features of home atmosphere are likewise being operated to render the habitation less fit for mites. The prospective occurs for evolving models of house dust mite populations, environmental features and influences of several tactics to control .
4. House dust mite fauna of prominence
Pyroglyphidae is divided into subfamily Pyroglyphinae wherein anterior extremity of the body is prolonged by a pointed or forked tegmen, which covers the base of the gnathosoma in both male and female, while tegmen absent in the second subfamily Dermatophagoidinae.
4.1 Subfamily Dermatophagoidinae Fain, 1963
Dermatophagoides farinaeHughes (American house dust mite)
American house dust mite
Duration of the life cycle at 16, 23, 30 and 35°C, and fecundity at 23°C and 75% RH have been determined for
Studies of the life cycle of cultured
Adopting the separate culturing technique, under a continuous temperature at 25°C, the effects of relative humidities of 86, 76, 61 and 36% on the life cycle of
Dermatophagoides pteronyssinus(Trouessart) (European house dust mite)
This particular species of mite has been found in all dust samples from many different countries in varying numbers. Hysteronotal shield of
The life cycle of
Dermatophagoides microcerasGriffiths and Cunnington (House dust mite, dust mite)
House dust mite
Dermatophagoides evansiFain, Hughes and Johnston
The life cycle of
4.2 Subfamily Pyroglyphinae Cunliffe, 1958
Female with the distal part of the bursa copulatrix in the form of a small, oval and strongly sclerotized pocket, while male is with anal suckers (
Euroglyphus maynei(Mayne’s house dust mite) (Cooreman)
The house dust mite
The reproductive biology of house dust mite
This species infests stored products, and is considered pests in granary debris, wheat, bean, oat, barley, rice, dried clover and hide dust . Data used for identification of this mite are the following: length of idiosoma is 245–265 μm and posterior edge of idiosoma with 2 distinct lobes each having 3 hairs. Male (darker, smaller) internal and external scapular setae and II pair of legs in line, a small hexagonal anal plate distant from posterior edge of body, anal suckers present, while trochanters I–III with one hair. Female (paler, larger) internal base of seminal receptacle simple, while posterior vulval lip or membrane long and almost entirely covering the vulva (on genital plate external genital opening). Hairs go, ae and those on trochanters I–III present.
The determination of the life cycle of the mite species has provided vital information on its biology showing that pre-reproductive period from mating to birth of first eggs is 12.78 ± 1.06 days and reproductive period between production of first and last eggs 39.78 ± 4.99 days. Fecundity, the total number of eggs laid per female is 48.00 ± 3.89 and rate of reproduction calculated as the number of eggs laid per of female’s reproductive period 1.33 ± 0.18. Finally, the development of immatures is completed in 30.14 ± 3.4 days .
The house dust mites
Knowledge of the mite species prevalence and density in a patient’s home is important in evaluating the role of mites as allergens, and in selecting and assessing effective immunotherapy for individual cases. Many species of mites besides
There are 47 different species of house dust mites, and dust mites
5. Epidemiology of house dust mites
For a lot of years, it has been advocated that allergens resulting from house dust mite show a foremost part in pathogenesis of eczema, asthma and certain circumstances of allergic rhinitis. In recent times, allergens by house dust mite have been refined and precise immunoassays established with which acquaintance to allergens and house dust mites can be more simply determined. By means of these tools, epidemiological homework have delivered positive confirmation that not merely house dust mite acquaintance has been linked with the majority of asthma cases in young adults and children but then again that it is causally connected to asthma development. Two main allergenic dust mite species,
Epidemiologic data available on incidence of house dust mites in residences demonstrate a perfect relationship among increased interior air humidity and increased existence of dust mites in house dust. Moreover, in temperate climates, there is threshold level of indoor air humidity 7 g/kg (45% relative humidity at normal indoor air temperature). Interior air humidity under this level for prolonged times will eliminate house dust mites from residences. A decrease in residents involvement to house dust mites is executed by lessening of indoor air humidity through organized mechanical air circulation. Individually, ventilation levels are assessed from actual house size, inhabitant numbers and mean outdoor air humidity in winter. In divergence, more moist zones of the world with mean outdoor humidity beyond 6–7 g/kg in winter will keep up great densities of house dust mites uniformly and a decrease in indoor air humidity will have a relatively slight effect on existence of house dust mites. Modern construction of energy-efficient houses by better fastening of building envelope, paralleled by an alike makeover of older houses, has increased indoor air humidity and is perhaps the cause of nearly fourfold rise in incidence of house dust mites in residences .
There are up to 2 million dust mites living in a standard mattress. Dust mites produce mite feces, which add up to 200 times of their own body weight within their lives of 2 months . Although exposure to house dust mite allergen is a major risk factor for allergic sensitization and asthma, the percentages of homes with dust mite allergen concentrations at or greater than detection, 2.0 μg bed dust and 10.0 μg bed dust, have been estimated to be 46.2, and 24.2%, respectively. Independent predictors of higher levels have been lower household income, older homes, no resident children, single-family homes, musty or mildew odor, heating sources other than forced air and higher humidity in bedroom. Most of homes in a bed have measurable levels of dust mite allergen. Levels earlier allied to allergic asthma and sensitization in bedrooms are common. Predictors can be utilized to detect situations under which homes are more possibly to have greater levels of dust mite allergen .
Epidemiologic works  studying the relationship among house dust mite distribution and outdoor humidity level have revealed that: (1) Outdoor humidity level that is reliant on climate of region and altitude is linked to house dust mite distribution, and peak number of mites is originated in the most moist regions. (2) Indoor humidity level that is reliant upon seasonal difference in outdoor humidity is connected to number of mites and the greatest number of mites is originated during the months wherever indoor humidity level is at peak. (3) Pronounced variances in the number of mites in diverse residences at the same time of year and in same area can be attributed owing to changes in indoor air humidity among residences.
Additional studies  recommend that there is a lesser edge of absolute humidity of 7.0 g water vapor/kg dry air, equivalent to 45% relative humidity at 20–23oC, under that house dust mites will not multiply. In residences with less than 7.0 g/kg, vapour house dust mites will arise as background contamination only and in numbers commonly below 100 mites/g dust.
For geographic regions with a temperate environment, it can be identified rather exactly that in order to stop buildup of hazardous levels of house dust mites in residences, indoor air humidity might be kept under a level of 7.0 g/kg or 45% relative humidity at usual indoor air temperature for a small number of winter months for every year. This extreme absolute humidity level in air indoor once more can be altered into a tiniest ventilation level stated in ACH (air changes per hour that strips with geographical locality (average outdoor air humidity in three dry winter months)) and inhabitants mass in the residence. As a whole, if (1) average outdoor air humidity in three winter months is recognized, (2) it is expected that each occupant of family creates a mean of 3000 g water vapor/24 hour in the residence, (3) water vapor is rapidly disseminated similarly to all air in construction, (4) rooms have a 2.0 m ceiling height, (5) a security margin of 30% is added to the minimum ventilation level, and steady-state situation can be calculated (production of water vapor divided by elimination equals 1):
From these calculations, figures can be made that the lowest ventilation desired may without difficulty be assessed with variable family size and space of the residence. Climate analysis with controlled and improved building ventilation is presently used to eradicate house dust mites from residences occupied by patients with asthma caused by allergy due to house dust mites .
6. Prevalence of house dust mites
The precise nature of dust mite density or the seasonal populations of house mites in homes are of paramount importance to reduce their development and in clarifying the role they play in dust allergy. A surrounding relative humidity is an important feature that controls prevalence and geographic spreading of these mites. This is for the reason that in humid air water vapors are key source of liquid for their existence. They thrive and survive fine at relative humidity exceeding 50%, however dry and decease at relative humidity less than this. As a result, dust mites and allergens they produce are an important problem merely for persons who live in moist temperate and tropical geographic regions. Mites
Significantly, higher abundance levels of the house dust mites
Of the systematically isolated mites from house dust samples, 90% are pyroglyphids, with 75% of these
It is well known that mite prevalence is greater in more humid geographic areas than in dry ones. Outdoor climatic conditions and indoor ambient RH are essentially the same for all homes in similar vicinity. Therefore, differences in mite abundance must be associated with other features of the homes (RH in mite microhabitat) and persons residing in these. A very important factor that correlates with the level of mite prevalence is the presence or absence of carpeting. Carpeted floors contain significantly more mites than tile or wood floors and none or very few mites are found on wood or vinyl-covered floors. Apparently, long-pile carpets reduce the efficiency of vacuuming and provide an excellent microhabitat for accumulation of food material and moisture for mites survival and breeding. From homes of house dust-sensitive patients, removing of fitted carpet would decrease the level of mites contact making from floors. Anywhere this cannot be undertaken or is not desirable; usage of short-pile carpets rather than large rough pile types would deal with important decline in levels of mites .
7. Phylogenetic relationships of family Pyroglyphidae
The pyroglyphids presently consist of 47 species and 20 genera, whose species are parasites associated with birds and mammals that contribute to house dust allergy problem. There has been no detailed phylogenetic analysis of the family Pyroglyphidae. However, in essence, pyroglyphids are initially bird’s-nest inhabitants; however they experienced an alteration in habitation to human nest and bed around the time of the first human settlement and are linked with agrarian production, specifically 10,000 years before. The glycyphagoid and acaroid mites of human residences made habitat transference from nests of small mammals and also come across habitat correspondences within homes, with diets in the form of cereals, seeds and other plant resources. By giving the similarity of trophic niches of human residences to those existing naturally, it is not astonishing that a number of mite species have become allied to human dwellings. Most importantly, many species of pyroglyphoid, glycyphagoid and acaroid appeared to have retained the ancestral ability to feed on fungi . The “host” relationships with birds point out that both subfamilies of pyroglyphids that comprise species found in house dust, Dermatophagoidinae and Pyroglyphinae, are geographically the most widespread and species-rich, and connected with a greater variety of avian taxa than those subfamilies which do not comprise species that are found in house dust. This has a tendency to advocate that Dermatophagoidinae and Pyroglyphinae might denote ancestral taxa within family.
8. Dust mites management
The most effective way to treat dust mite allergies is to eliminate as many dust mites as possible from homes. Dust mites cannot be completely eliminated from home; however, they can be reduced. Reducing dust mites in houses can eliminate or lessen dust mite allergies. Having great physician care and sublingual treatment of dust mite allergies along with cleanup and prevention can be the keys in controlling of dust mite allergies.
8.1 Dust mite allergy treatment
Generally, people who have dust allergies are familiar with sneezing (act of expelling a sudden and uncontrollable burst of air through the nose and mouth), but sneezing is not the only uncomfortable symptom. Typically, sneezing occurs after external elements, or an adequate outside stimulating substance moves across nasal hairs to touch the nasal mucosa. This activates the discharge of histamines that irritate the nerve cells in the nose, causing signals being sent to the brain to start sneezing through the trigeminal nerve complex. The function of sneezing is to expel mucus containing irritants from the nasal cavity [55, 56].
Dust allergies also give to many people a stuffy or runny nose or cause their eyes to itch or become red and watery. A house is thought to be a cheering shelter; however for people having dust allergies, a home can generate painful indications. Strangely sufficient, allergy signs frequently get worse for the period of vacuuming or immediately after it, sweeping and dusting at a place. The practice of dusting can bring dirt particles up by creating these easier to breathe inside. If a person thinks he or she may have an allergy to any of the components of house dust, then see an allergist to pinpoint the cause of symptoms. Often an allergist will need to conduct a skin test and may order a blood test to determine exactly what is triggering an allergic reaction. After a dust allergy is identified, an allergist may recommend one or more of the treatments such as medications, allergy shots (subcutaneous immunotherapy), tablets (oral immunotherapy) and changes to personal household routine. A person may be prescribed by antihistamines to relieve sneezing, runny and stuffed nose, and itching in the nose and eyes; nasal corticosteroids to reduce swelling in nose and block allergic reactions; commonly sodium nose spray to block the release of chemicals that cause allergy symptoms, including histamine and leukotrienes; leukotriene antagonists, pills which can improve both allergy and asthma symptoms; decongestant pills, liquids and allergy shots; and dust mite sublingual immunotherapy in which tablets of dust mite purified protein are placed under the tongue that may prevent and decrease symptoms of dust mite allergies .
8.2 Dust mite prevention strategies
No matter how much clean a home is, dust mites cannot be completely eliminated. However, as a first line of defense, dust mite mass can be condensed by exploiting the subsequent practices. Practice a dehumidifier or an air conditioner to keep humidity intensities at or lower than 50%. Enclose pillows and mattress in dustproof protections or allergen-resistant shelters. Wash down all blankets and bedding in hot water at 130–140°F to kill dust mites, once a week, and non-washable bedclothes can be kept cold overnight. Change feathered or wool bedding articles with synthetic materials and traditional animal stuffed products by washable ones. Within bedrooms, change wall-to-wall fitted carpet by naked floors, and get rid of fabric curtains and covered furniture, at whatever time imaginable. Practice a moist cleaner or duster to get rid of dust and at no time use a dry cloth, as it rises allergens up. Utilize a double-layered microfilter sack or a high-efficiency particulate air filter in a vacuum cleaner. Wear a mask while vacuuming, and stay out of the vacuumed area for 20 minutes after vacuuming, to allow dust and allergens to settle. The dust mite prevalence could be kept very low, and the factors responsible for the low mite density are maintenance of low relative humidity, use of low-pile carpets, and good housekeeping and laundering practices .
8.3 Control of house dust mites
An abstract of the study identifies that air conditioning can lessen relative humidity and population of dust mite in home environment in comparison to homes without dehumidification or air conditioning. However, humidity lessening does not stop populations of mites from developing further than the threshold of inducing allergies. An air-conditioning usage in combination with an efficient dehumidifier is effective in dropping of relative humidity in these homes lower than the threshold needed for mite population development, reproduction and growth. Subsequent to fourth week of study, 75% of dehumidifiers fitted homes have zero amount of live mites. House dust mites in clothing and bedding are the source of major allergens, and an average threshold before developing allergies is 100 mites/g of dust [59, 60].
Based upon studies of only
People can use mite killers (a number of powders and sprays are available) on mite-infested materials and reapply these occasionally as per manufacturer’s directions. Furthermore, antibiotics have been tested, aiming at the control of
Copper oxide (CuO) has broad-spectrum antimicrobial and antifungal properties and a study taken on common
9. Domestic mites and forensic science
In fact, mites can be found in all habitats, even in the pores of our skin and almost every single person carries mites. Thus, they may even proof useful, for instance, in forensics. More than 100 species of mites from over 60 families are collected from animal carcasses and approximately 75 mite species from over 20 families gathered from human corpses , also including the astigmatid mite taxa. Domestic mites and other dust mites are present globally; however composition of species can be different between seasons, dwellings and even within places of a same indoor atmosphere (floors vs. stuffing furniture, floors vs. beds, or dust from a library desk vs. bookshelves). Distinguished variances in acarofauna of house dust mites among locations can provide valuable facts, for example, as an indicator of time and statuses of a death .
Surveys of dust samples have been taken from dwellings, hospitals, libraries, research laboratories, drugstores, offices and other workplaces. More than 30 mite species are found of which the most abundant and common include dust mites especially
Since dust mites feed on the flakes of shed human skin, so human genetic material is expected to be present in these creatures. A study has been conducted to find out if house dust mites can carry the DNA of the house occupants. If this is true, human DNA isolated from the mites, obtained from a crime scene, could be used as evidence in court. The DNA profiles of people (10.25%) from homes (96.3%) showed an exact match with those found in the mite samples from the same house . So, identified human DNA in house dust mites suggests that one can investigate a crime by analyzing DNA samples from house dust mites found in a crime scene and by comparing them with the DNA profiles obtained from victims and suspects.
The blowflies or flesh flies might carry out their life cycle around and in dead body, whereas mites may well forage on young stages of flies. The mites might breed more quickly than their fly carriers, posing themselves as appreciated timeline markers . There are atmospheres at someplace where insects are either rare or absent, or the ecological situations hinder in their contact to carcass. At this point, mites that are previously present and mites which reach through air currents, by walking, or with material transfer come to be vital. There are eight different waves of arthropods colonizing carcasses of human. The first wave comprises flies and mites, whereas sixth wave is exclusively made up of mites. The scope of forensic acarology goes further in forensic investigations as mites compete with insects for food (dead body), slowing their development, or may even feed on insects. Observing mites can improve estimations of postmortem intervals that rely on timeline of when various species usually reach on a carcass and in whatever way long they proceed to grow, thus letting for more precise estimates in murder case. Mites are specific to microhabitat and might deliver evidential data on relocation or movement of bodies or finding a doubt at a crime scene . Therefore, dust mites can be used as evidence in fields of forensic sciences.
House dust mites got their names from habitat of household dust and feed on any protein that comes in their way and find easy pickings in the dead skin scales that humans shed every day. House dust mites are not insects but arachnids and relate to spiders and ticks by having lengthy legs. Thirteen important house dust mite species have been identified; but two species that are the greatly common and key cause of allergen include
Strategies to reduce dust mites in homes include to cover mattresses, pillows, and quilts with dust mite-resistant covers; wash sheets and pillowcases weekly in water hotter than 55°C; hot tumble dry (for half an hour after dry) or dry clean household items; wash blankets every 2 months; use synthetic rather than feather pillows; remove sheepskin or woolen underlays; remove all soft toys from bedroom and replace with wooden or plastic toys; damp dust or use electrostatic cloths to clean hard surfaces weekly; reduce humidity to have a dry and well-ventilated house; avoid upholstered furniture; avoid heavy curtains; wash clothing before use if stored for a long time; as well as remove carpets and vacuum home weekly. The truth is that the utility of mites especially in cases where conditions such as the environment of the corpse it is found and the manner of death are not suitable for the presence or arrival of insects, mite populations on corpses can become an important evidence for elucidating of forensic cases.