*4.1.4* Dermatophagoides evansi *Fain, Hughes and Johnston*

*Parasitology and Microbiology Research*

*dust mite)*

epimera I free (and first legs normal) [33].

The ranges of life longevity of mated males and females are 18–64 and 20–54 days, respectively. At 76% RH, mite *D. pteronyssinus* exhibited the shortest duration of development. It took a total duration of 37.1 ± 2.5 days with a range from 30 to 54 days, for egg 6.2 ± 0.3 days, for larva 10.7 ± 0.3 days, for protonymph 8.6 ± 1.0 days and for tritonymph 11.4 ± 2.2 days. The largest total number of eggs, 76.2+22.2, is laid by a female of *D. pteronyssinus.* In a 10-week life span, a house dust mite will produce approximately 2000 fecal particles and an even larger number of partially digested enzyme-covered dust particles. The conditions used in the rearing experiments may be considered optimal for maintaining culture of *D. pteronyssinus* [32].

*4.1.3* Dermatophagoides microceras *Griffiths and Cunnington (House dust mite,* 

House dust mite *Dermatophagoides microceras* Griffiths and Cunnington (**Figure 4**) is a species first described in 1971 and part of the Pyroglyphidae family of mites. This mite has been identified in house dust in various geographic regions, including Great Britain, Scandinavia, the Netherlands, Spain and United States; however its distribution in the rest of the world has not been explored well. Morphologically, males tarsus I is without small apical protuberance (process S), but with curved spine and tarsus II without process S or spine. Females tarsus I with short, straight, blunted spine, tarsus II lacking spine and bursa copulatrix narrow as well as weakly sclerotized in region adjacent to external opening. In females, propodonotal shield is about 1.4 times as lengthy as wide; idiosoma 395–435 μm in length; vestibule of bursa absent, bursa unfastens at the bottom of a non-sclerotized depression of tegmen; first portion of bursa proper is a little dilated and clearly sclerotized; and apical progression of tarsus I mostly very minor or absent. In males, idiosoma is 285–345 μm in length; males either heteromorphic with epimera I joined to form a V or Y shape (and first legs enlarged) or homeomorphic with

*D. microceras* is more closely related to *D. farinae*, and the biological and immunochemical identification of these two species are argued. Using an enzymelinked immunosorbent assay (ELISA) technique, the response of mite material from different stock cultures demonstrated that *D. farinae* and *D. microceras* are discrete entities, and also at the major allergen level, with no apparent subspecies or strain variation. Females of *D. farinae* and *D. microceras* receptaculum seminis not U-shaped in cross section, while males with hysteronotal shield as long as broad and extending anteriorly to point between setae d1 and e or slightly anterior of d1 [34].

**280**

**Figure 4.**

Dermatophagoides microceras.

Specifically, *Dermatophagoides evansi* Fain (**Figure 5**) Hughes and Johnston mites are found in the poultry dust samples and also in bird's nests. Hen poultry farmers and their families, but also other professionals working in the poultry industry, such as veterinarians, may be exposed to house dust mites. In females, bursa copulatrix is strongly enlarged in its distal third and very narrow in proximal two thirds (internal); and spermatheca sclerotized and tulip-like. In males, hysteronotal shield markedly spread frontward away from bases of setae d1; adanal suckers 12 μm in span; coxae II shut; legs III 1.8 times denser (at level of femur) and 1.6 times lengthier (length of 4 distal segments) than legs IV; tarsus I with 2 uneven apical progressions (ongles); tarsus II with a slight apical progression; setae cp 110 μm in length; setae d2 located at 55–65 μm from opening of fat gland; setae h2 and h3 with bases intensely sclerotized; epimera I free; and males are homeomorphic. The males differ from males of *D. pteronyssinus* primarily through dorsal hysterosomal shield that is longer and narrower; ratio width (at level of setae d1):length = 1:2.5 [whereas in *D. pteronyssinus* this ratio is 1.8–1.9]; while legs III and IV are much more unequal than in *D. pteronyssinus* [35].

The life cycle of *D. evansi* has been studied and reared at a relative humidity of 75–80% and temperature 25–27°C in a medium consisted of human skin or chicken skin scales plus baker's yeast powder. The average period of mite life cycle for each stage in days is the following: egg 8.3; larva and protonymph 5.4; tritonymph 6.6; female 52.9; and male 28.9. The mean time necessary for accomplishment of one generation is 28.7 days. The female is oviparous, parthenogenesis not detected, and lays 35.5 mean eggs during its life span. The adults copulate repeatedly and the female-male ratio is 1:1.2 [36].

## **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* Fain), but male and female are without this combination of characters in *Pyroglyphus*. In *Euroglyphus maynei* (Cooreman), male trochanters I–III without hairs and is with a large oval anal plate spreading near to posterior edge of body, while female hairs ga, ae and those of trochanters I–III missing, and have a small posterior vulval lip that does not shelter to anterior of vulva. In case of *Euroglyphus longior* (Trouessart), male trochanters I–III with one hair and is with a minute hexagonal anal plate distant from posterior edge of the body. Female hairs ga, ae and those on trochanters I–III present, and posterior vulval lip is long nearly completely casing to vulva.

**Figure 5.** Dermatophagoides evansi.

#### *4.2.1* Euroglyphus maynei *(Mayne's house dust mite) (Cooreman)*

The house dust mite *Euroglyphus maynei* (Cooreman) (**Figure 6**) infests stored products and is considered pests in cottonseed meal, bean curd, Chinese medicines, crabmeat and shrimps. This occurs in homes worldwide and is an important source of many allergens. Differential diagnosis in both sexes; setae sci and sce about the same length and tegmen (t) present. Length of idiosoma 195–225 μm; posterior edge of idiosoma with 2 minute lobes without hairs; tegmen well developed, triangular with rounded apex (not bifid in the male); cuticle somewhat sclerotized with rather fine formed markings or creases; hysteronotum within a median shield with margins poorly distinct; anterior legs missing chitinous membranes; chaetotaxy condensed; tibials IV, trochanterals I–III, anal external setae and genital anterior setae are absent; tarsi IV with 3 setae; tarsi III with 5 setae; dorsal setae very short and thin; setae h3 very short (maximum length 50 μm) and thin; setae h2 very thin and short (not more than 30 μm); and genu I with one solenidion. In males, tegmen with unforked, rounded apex; dorsal setae variable; opisthosoma slightly but narrowed backwards regularly; anus more posterior (anal suckers situated at 25 μm from posterior body margin); posterior body margin wide and straight with 2 small paramedian lobes; adanal suckers well developed; and tarsi IV lacking suckers. In females, setae sce short (maximum 50 μm) and thin; at bases of legs II no chitinous pouches; tegmen either prominent and triangular but with apex rounded and not forked or poorly developed and rounded with a small median notch; posterior lip of vulva short and punctate, not covering vulvar slit; or anterior angle of posterior vulvar lip not incised; vulva uncovered; tegmen triangular with rounded, not incised apex; hysteronotum striated with a median shield; copulatory vestibule ovoid, strongly sclerotized and opaque; and tarsi I–IV without apical processes nor spines [37].

The reproductive biology of house dust mite *E. maynei* is not studied well. This mite is generally less common than *D. pteronyssinus* and *D*. *farinae* in homes*.* While it is present, it commonly coinhabits with species of *Dermatophagoides* and in geographic distribution, is more restricted. The period of life cycle (egg to adult) for *E. maynei* at 75% relative humidity as well as 23 and 30°C and fecundity at 75% RH and 23°C have been concluded, and data compared similar to data for *D. pteronyssinus* and *D. farinae*. Adults hatched from eggs at 23°C after 28 days and at 30°C in 20 days. At 23°C, females during a reproductive period of 24 days produced 1.4 eggs/day. At 23°C, mite *E. maynei* has a smaller life cycle than *D. pteronyssinus* and *D. farinae*; however, at 30°C, this have a lengthier life cycle and produced fewer eggs than both mites [38].

**283**

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination*

This species infests stored products, and is considered pests in granary debris,

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

The house dust mites *D. farinae*, *D. pteronyssinus* and *E. maynei* are cosmopolitan inhabitants of human dwellings. They are most prevalent in high-use areas in homes (e.g., beds, furniture, floors), where shed human skin scales are collected and serve as a source of food. Relative humidity is an important factor regulating the geographic prevalence and density of these mites. In humid geographic areas, most homes contain mite populations, whereas in dry (low-humidity) geographic areas, few homes contain mites. The species prevalence and density of these mites varies both geographically and between homes in the same geographic area. Although factors influencing variation in mite density between homes are not well understood, it appears that mite density is not correlated with housecleaning practices. However, carpeted floors support significantly greater mite populations than do wood or tile floors. A home may contain only one species or multiple species may coexist. Most homes are coinhabited by more than one species. In coinhabited homes, one species generally constitutes the greatest percentage of the total population, but the

dominant species varies between homes within a geographic area [41].

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 *D. farinae*, *D. pteronyssinus* and *E. maynei* may occur in homes, at times in significant numbers. Therefore, one must be careful when conducting mite surveys to differentiate between not only the primary allergy-causing species but other species as well if species and density determinations are to be accurate and meaningful. House dust mites live in a microenvironment in which no liquid water is present. However, their bodies are 70–80% water by weight, which must be maintained above a critical lower limit in order to survive. Active life stages are able to survive at ambient humidities as low as 60% relative humidity because they extract sufficient water directly from unsaturated air by means of a special adaptation to compensate for water losses. A desiccation-resistant protonymph can survive prolonged periods at low relative humidity and this stage probably serves as a source of mites for breed-

There are 47 different species of house dust mites, and dust mites *D. farinae*, *D. pteronyssinus* and *E. maynei* are sources of multiple potent allergens in the indoor environment. An ambient RH is a key factor in determining where these mites are found. Bedding, carpeting, and furniture cushions all trap and hold moisture,

wheat, bean, oat, barley, rice, dried clover and hide dust [39]. 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

*DOI: http://dx.doi.org/10.5772/intechopen.91891*

*4.2.2* Euroglyphus longior *(Trouessart)*

those on trochanters I–III present*.*

completed in 30.14 ± 3.4 days [40].

ing during optimal conditions [42].

**Figure 6.** Euroglyphus maynei.

#### *4.2.2* Euroglyphus longior *(Trouessart)*

*Parasitology and Microbiology Research*

*4.2.1* Euroglyphus maynei *(Mayne's house dust mite) (Cooreman)*

The house dust mite *Euroglyphus maynei* (Cooreman) (**Figure 6**) infests stored products and is considered pests in cottonseed meal, bean curd, Chinese medicines, crabmeat and shrimps. This occurs in homes worldwide and is an important source of many allergens. Differential diagnosis in both sexes; setae sci and sce about the same length and tegmen (t) present. Length of idiosoma 195–225 μm; posterior edge of idiosoma with 2 minute lobes without hairs; tegmen well developed, triangular with rounded apex (not bifid in the male); cuticle somewhat sclerotized with rather fine formed markings or creases; hysteronotum within a median shield with margins poorly distinct; anterior legs missing chitinous membranes; chaetotaxy condensed; tibials IV, trochanterals I–III, anal external setae and genital anterior setae are absent; tarsi IV with 3 setae; tarsi III with 5 setae; dorsal setae very short and thin; setae h3 very short (maximum length 50 μm) and thin; setae h2 very thin and short (not more than 30 μm); and genu I with one solenidion. In males, tegmen with unforked, rounded apex; dorsal setae variable; opisthosoma slightly but narrowed backwards regularly; anus more posterior (anal suckers situated at 25 μm from posterior body margin); posterior body margin wide and straight with 2 small paramedian lobes; adanal suckers well developed; and tarsi IV lacking suckers. In females, setae sce short (maximum 50 μm) and thin; at bases of legs II no chitinous pouches; tegmen either prominent and triangular but with apex rounded and not forked or poorly developed and rounded with a small median notch; posterior lip of vulva short and punctate, not covering vulvar slit; or anterior angle of posterior vulvar lip not incised; vulva uncovered; tegmen triangular with rounded, not incised apex; hysteronotum striated with a median shield; copulatory vestibule ovoid, strongly sclerotized and opaque; and tarsi I–IV without apical processes nor

The reproductive biology of house dust mite *E. maynei* is not studied well. This mite is generally less common than *D. pteronyssinus* and *D*. *farinae* in homes*.* While it is present, it commonly coinhabits with species of *Dermatophagoides* and in geographic distribution, is more restricted. The period of life cycle (egg to adult) for *E. maynei* at 75% relative humidity as well as 23 and 30°C and fecundity at 75% RH and 23°C have been concluded, and data compared similar to data for *D. pteronyssinus* and *D. farinae*. Adults hatched from eggs at 23°C after 28 days and at 30°C in 20 days. At 23°C, females during a reproductive period of 24 days produced 1.4 eggs/day. At 23°C, mite *E. maynei* has a smaller life cycle than *D. pteronyssinus* and *D. farinae*; however, at 30°C, this have a lengthier life cycle and produced fewer

**282**

**Figure 6.**

Euroglyphus maynei.

spines [37].

eggs than both mites [38].

This species infests stored products, and is considered pests in granary debris, wheat, bean, oat, barley, rice, dried clover and hide dust [39]. 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 [40].

The house dust mites *D. farinae*, *D. pteronyssinus* and *E. maynei* are cosmopolitan inhabitants of human dwellings. They are most prevalent in high-use areas in homes (e.g., beds, furniture, floors), where shed human skin scales are collected and serve as a source of food. Relative humidity is an important factor regulating the geographic prevalence and density of these mites. In humid geographic areas, most homes contain mite populations, whereas in dry (low-humidity) geographic areas, few homes contain mites. The species prevalence and density of these mites varies both geographically and between homes in the same geographic area. Although factors influencing variation in mite density between homes are not well understood, it appears that mite density is not correlated with housecleaning practices. However, carpeted floors support significantly greater mite populations than do wood or tile floors. A home may contain only one species or multiple species may coexist. Most homes are coinhabited by more than one species. In coinhabited homes, one species generally constitutes the greatest percentage of the total population, but the dominant species varies between homes within a geographic area [41].

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 *D. farinae*, *D. pteronyssinus* and *E. maynei* may occur in homes, at times in significant numbers. Therefore, one must be careful when conducting mite surveys to differentiate between not only the primary allergy-causing species but other species as well if species and density determinations are to be accurate and meaningful. House dust mites live in a microenvironment in which no liquid water is present. However, their bodies are 70–80% water by weight, which must be maintained above a critical lower limit in order to survive. Active life stages are able to survive at ambient humidities as low as 60% relative humidity because they extract sufficient water directly from unsaturated air by means of a special adaptation to compensate for water losses. A desiccation-resistant protonymph can survive prolonged periods at low relative humidity and this stage probably serves as a source of mites for breeding during optimal conditions [42].

There are 47 different species of house dust mites, and dust mites *D. farinae*, *D. pteronyssinus* and *E. maynei* are sources of multiple potent allergens in the indoor environment. An ambient RH is a key factor in determining where these mites are found. Bedding, carpeting, and furniture cushions all trap and hold moisture,

allowing these tiny creatures to flourish. Dust mites settle down in carpet, draperies, stuffed animals and upholstered furniture. Mattresses, pillows and soft bedding are favorite hangouts [43]. These same symptoms can be caused by a variety of other allergens as well, so consultancy to an allergist is needed for their testing. To diagnose a dust mite allergy, a physician may suggest a skin test [skin prick test (SPT)] or blood test (specific IgE blood test).

#### **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, *D. pteronyssinus* and *D. farina*e, are important components in the development of asthma [44].

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 [45].

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 [46]. 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 [47].

Epidemiologic works [48] 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)

**285**

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination*

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 [49] 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 20–23o

For geographic regions with a temperate environment, it can be identified rather

1 = *N* × 3000 × 1.3/ m<sup>2</sup> × 2 × (indoor AH − outdoor AH) × ach × 24 (1)

From these calculations, figures can be made that the lowest ventilation desired

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 *D. pteronyssinus* and/ or *D. farinae* are prevalent in homes in Asia, Europe, the United States, and South America. However, most home environment are coinhabited by several species, but then again the greatest species prevalence differs both between homes in a

in square meters, indoor AH = maximum wanted indoor air absolute humidity (usually set to 7.0 g/kg), outdoor AH = average 3-month outdoor absolute humidity (three most dry winter months), and ACH = air changes per hour (ACH of 1.0

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

where *N* = absolute number of inhabitants in household, m<sup>2</sup>

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 num-

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

C,

= area of dwelling

*DOI: http://dx.doi.org/10.5772/intechopen.91891*

bers commonly below 100 mites/g dust.

vapor divided by elimination equals 1):

**6. Prevalence of house dust mites**

means that all air is exchanged once every hour).

with asthma caused by allergy due to house dust mites [45].

#### *House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination DOI: http://dx.doi.org/10.5772/intechopen.91891*

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 [49] 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 20–23o C, 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):

$$\mathbf{1} = \mathbf{N} \times \mathbf{3000} \times \mathbf{1}.3/\mathbf{m}^2 \times \mathbf{2} \times \text{(indoor AH - outdoor AH)} \times \mathbf{a} \mathbf{b} \times \mathbf{24} \tag{1}$$

where *N* = absolute number of inhabitants in household, m<sup>2</sup> = area of dwelling in square meters, indoor AH = maximum wanted indoor air absolute humidity (usually set to 7.0 g/kg), outdoor AH = average 3-month outdoor absolute humidity (three most dry winter months), and ACH = air changes per hour (ACH of 1.0 means that all air is exchanged once every hour).

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 [45].

## **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 *D. pteronyssinus* and/ or *D. farinae* are prevalent in homes in Asia, Europe, the United States, and South America. However, most home environment are coinhabited by several species, but then again the greatest species prevalence differs both between homes in a

*Parasitology and Microbiology Research*

or blood test (specific IgE blood test).

**5. Epidemiology of house dust mites**

are important components in the development of asthma [44].

fourfold rise in incidence of house dust mites in residences [45].

allowing these tiny creatures to flourish. Dust mites settle down in carpet, draperies, stuffed animals and upholstered furniture. Mattresses, pillows and soft bedding are favorite hangouts [43]. These same symptoms can be caused by a variety of other allergens as well, so consultancy to an allergist is needed for their testing. To diagnose a dust mite allergy, a physician may suggest a skin test [skin prick test (SPT)]

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, *D. pteronyssinus* and *D. farina*e,

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

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 [46]. 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

Epidemiologic works [48] 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)

**284**

mite allergen [47].

geographic region and between geographic regions. For instance, in the United States, both *D. pteronyssinus* and *D. farinae* are prevalent in homes; however *D. farinae* is more prevalent in homes than *D. pteronyssinus* within northern moist environments. However, in South America, *D. pteronyssinus* is prevalent in homes, whereas *D. farinae* is not. In temperate type of weather, densities of *D. pteronyssinus* and *D. farinae* display distinct periodic variations that are equivalent to seasonal instabilities in indoor relative humidity. Their great densities arise for the duration of moist summer months and little densities in winter, while relative humidity in homes is low [50].

Significantly, higher abundance levels of the house dust mites *D. farinae* and *D. pteronyssinus* arise on the most greatly used carpeted floor areas and fabricupholstered furniture by the family living in bedrooms and room. Mattresses do not originate to be the key foci for occurrence of mites. There is no major positive correlation known among frequency or thoroughness of cleaning and mite abundance, as well as age of furnishings or dwelling and amount of dust. Considerably, greater mite levels arise on carpeted floorings than on non-carpeted grounds. A continuous vacuuming does not considerably decrease abundance of mites. Density of mites demonstrated a seasonal variability, with the lowermost mass during dryer along with late heating season and the uppermost mass arising in humid summer months. Alive mites are more plentiful than deceased mites for the period when overall abundance is great. In homes occupied by both mite species, *D. farinae* is more prevailing, excluding in one home that has considerably a greater relative humidity [51].

Of the systematically isolated mites from house dust samples, 90% are pyroglyphids, with 75% of these *D. pteronyssinus*, 10.5% *D. farinae* and 3.6% *E. maynei*, while Cheyletidae constituted 5.7% of the house dust mites. The maximum number of house dust mites recorded is 6500/g of house dust and the highest numbers are isolated in samples from humid areas (Feldman-Muhsam et al. 1985). Mites are present in 97% of the house dust samples and the maximum number of mites (7440/g dust) is found in the carpet. Most of the mites are isolated from the carpets and sofas (37.0 and 33.7%, respectively) and less from the beds (29.3%) [52].

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 [53].

### **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

**287**

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination*

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 [54]. 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

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 control-

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

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

expel mucus containing irritants from the nasal cavity [55, 56].

*DOI: http://dx.doi.org/10.5772/intechopen.91891*

ancestral taxa within family.

**8. Dust mites management**

ling of dust mite allergies.

**8.1 Dust mite allergy treatment**

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination DOI: http://dx.doi.org/10.5772/intechopen.91891*

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 [54]. 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**

*Parasitology and Microbiology Research*

homes is low [50].

humidity [51].

geographic region and between geographic regions. For instance, in the United States, both *D. pteronyssinus* and *D. farinae* are prevalent in homes; however *D. farinae* is more prevalent in homes than *D. pteronyssinus* within northern moist environments. However, in South America, *D. pteronyssinus* is prevalent in homes, whereas *D. farinae* is not. In temperate type of weather, densities of *D. pteronyssinus* and *D. farinae* display distinct periodic variations that are equivalent to seasonal instabilities in indoor relative humidity. Their great densities arise for the duration of moist summer months and little densities in winter, while relative humidity in

Significantly, higher abundance levels of the house dust mites *D. farinae* and *D. pteronyssinus* arise on the most greatly used carpeted floor areas and fabricupholstered furniture by the family living in bedrooms and room. Mattresses do not originate to be the key foci for occurrence of mites. There is no major positive correlation known among frequency or thoroughness of cleaning and mite abundance, as well as age of furnishings or dwelling and amount of dust. Considerably, greater mite levels arise on carpeted floorings than on non-carpeted grounds. A continuous vacuuming does not considerably decrease abundance of mites. Density of mites demonstrated a seasonal variability, with the lowermost mass during dryer along with late heating season and the uppermost mass arising in humid summer months. Alive mites are more plentiful than deceased mites for the period when overall abundance is great. In homes occupied by both mite species, *D. farinae* is more prevailing, excluding in one home that has considerably a greater relative

Of the systematically isolated mites from house dust samples, 90% are pyroglyphids, with 75% of these *D. pteronyssinus*, 10.5% *D. farinae* and 3.6% *E. maynei*, while Cheyletidae constituted 5.7% of the house dust mites. The maximum number of house dust mites recorded is 6500/g of house dust and the highest numbers are isolated in samples from humid areas (Feldman-Muhsam et al. 1985). Mites are present in 97% of the house dust samples and the maximum number of mites (7440/g dust) is found in the carpet. Most of the mites are isolated from the carpets and sofas (37.0 and 33.7%, respectively) and less from the beds (29.3%) [52]. 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

**286**

important decline in levels of mites [53].

**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

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 [57].

#### **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 nonwashable 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 [58].

#### **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 *D. pteronyssinus*, weekly washing of clothing and bedding in hot water is suggested to remove allergens and destroy dust mites. But, most often washing is done in cold or warm water and other species of mites are also involved. A study has investigated the fatal influence of different temperatures of hot water alone and hot, warm, and cold water comprising chlorine bleach and detergents on *D. farinae*, *E. maynei*, and *D. pteronyssinus*. Mites have been dipped in test solutions for various lengths of time and at various temperatures, permitted time to recover, and then examined for existence. Mite *D. farinae* has been noted to be the most sensitive to temperature and chlorine bleach among the other two species. In 50o C water alone, 100% death of *D. farinae* has been found within 10 minutes, while most *E. maynei* and *D. pteronyssinus* stayed alive. But, soaking for 5 and 12 minutes at 53<sup>o</sup> C has been required to destroy all *E. maynei* and *D. pteronyssinus*, respectively. Washing with cleansing agents at suggested and

**289**

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination*

noxaline, and a week later, no eggs have been found [62–65].

tions of house dust mites and the burden of dust mite allergens [66].

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 [67], 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

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

[69]. Thus, this knowledge may be useful in the field of forensic medicine.

) dust) are noted in dwellings

**9. Domestic mites and forensic science**

time and statuses of a death [68].

especially *D. farinae*. The highest mite densities (g (-1

doubled concentrations and chlorine bleach mostly increased mortalities of three mite species compared to water alone. Soaking in warm water comprising different detergents alone for 4 hours made mortalities of 2–35%, 14–46% and 19–50% for *D. pteronyssinus*, *E. maynei* and *D. farinae*, respectively. Weekly washing of bed linens in warm water comprising bleach and most detergents presoaked for 4 hours can kill maximum number of *D. farinae*, and depending on detergent brand destroy adequate numbers of *D. pteronyssinus*. With warm water comprising the suggested concentrations of different detergents, soaking alone for 4-hour also killed enough numbers of *E. maynei*, *D. farinae* and *D. pteronyssinus*. So, accumulative influence of weekly washing with long presoaks of bed linens must considerably decrease mite levels over time, mainly when pillows and mattresses are sealed to stop

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 *D. pteronyssinus* house dust mite. In culture medium, sulfaquinoxaline 30% within 3 weeks killed all the mites, whereas 30 mg/100 mg of culture medium of declomycin, oxytetracycline, tetracycline HCl, and aureomycin in 3 weeks killed 52, .058.9 and 94.6%, respectively, of mites. Cessations of nourishing and reduced coordination have been detected in mite cultures after 24 hours following the use of sulfaqui-

Copper oxide (CuO) has broad-spectrum antimicrobial and antifungal properties and a study taken on common *D. farinae* house dust mite has tested the acaricidal efficiency of CuO-impregnated fabrics. The general mobility or vitality of mites has been reduced when they are exposed to CuO-impregnated fabrics and when possible, dust mites transferred to fabrics where no CuO existed. The mortality of mites exposed for 10 days to fabrics containing 0.2% (w/w) CuO remained significantly higher than the mortality of mites on control fabrics (72 ± 4 and 18.9 ± 0.3%, respectively). The death rate reached to 95.4 and 100% after 47 and 5 days with fabrics comprising 0.4 and 2% CuO, respectively. The acaricidal influence of copper oxide appears because of direct toxicity, and usage of fabrics comprising copper oxide might therefore be a significant opportunity for decreasing popula-

*DOI: http://dx.doi.org/10.5772/intechopen.91891*

reinfestation [61].

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination DOI: http://dx.doi.org/10.5772/intechopen.91891*

doubled concentrations and chlorine bleach mostly increased mortalities of three mite species compared to water alone. Soaking in warm water comprising different detergents alone for 4 hours made mortalities of 2–35%, 14–46% and 19–50% for *D. pteronyssinus*, *E. maynei* and *D. farinae*, respectively. Weekly washing of bed linens in warm water comprising bleach and most detergents presoaked for 4 hours can kill maximum number of *D. farinae*, and depending on detergent brand destroy adequate numbers of *D. pteronyssinus*. With warm water comprising the suggested concentrations of different detergents, soaking alone for 4-hour also killed enough numbers of *E. maynei*, *D. farinae* and *D. pteronyssinus*. So, accumulative influence of weekly washing with long presoaks of bed linens must considerably decrease mite levels over time, mainly when pillows and mattresses are sealed to stop reinfestation [61].

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 *D. pteronyssinus* house dust mite. In culture medium, sulfaquinoxaline 30% within 3 weeks killed all the mites, whereas 30 mg/100 mg of culture medium of declomycin, oxytetracycline, tetracycline HCl, and aureomycin in 3 weeks killed 52, .058.9 and 94.6%, respectively, of mites. Cessations of nourishing and reduced coordination have been detected in mite cultures after 24 hours following the use of sulfaquinoxaline, and a week later, no eggs have been found [62–65].

Copper oxide (CuO) has broad-spectrum antimicrobial and antifungal properties and a study taken on common *D. farinae* house dust mite has tested the acaricidal efficiency of CuO-impregnated fabrics. The general mobility or vitality of mites has been reduced when they are exposed to CuO-impregnated fabrics and when possible, dust mites transferred to fabrics where no CuO existed. The mortality of mites exposed for 10 days to fabrics containing 0.2% (w/w) CuO remained significantly higher than the mortality of mites on control fabrics (72 ± 4 and 18.9 ± 0.3%, respectively). The death rate reached to 95.4 and 100% after 47 and 5 days with fabrics comprising 0.4 and 2% CuO, respectively. The acaricidal influence of copper oxide appears because of direct toxicity, and usage of fabrics comprising copper oxide might therefore be a significant opportunity for decreasing populations of house dust mites and the burden of dust mite allergens [66].

#### **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 [67], 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 [68].

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 *D. farinae*. The highest mite densities (g (-1 ) dust) are noted in dwellings [69]. Thus, this knowledge may be useful in the field of forensic medicine.

*Parasitology and Microbiology Research*

**8.2 Dust mite prevention strategies**

**8.3 Control of house dust mites**

of dust [59, 60].

other two species. In 50o

soaking for 5 and 12 minutes at 53<sup>o</sup>

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

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 nonwashable 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

tongue that may prevent and decrease symptoms of dust mite allergies [57].

of low-pile carpets, and good housekeeping and laundering practices [58].

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

Based upon studies of only *D. pteronyssinus*, weekly washing of clothing and bedding in hot water is suggested to remove allergens and destroy dust mites. But, most often washing is done in cold or warm water and other species of mites are also involved. A study has investigated the fatal influence of different temperatures of hot water alone and hot, warm, and cold water comprising chlorine bleach and detergents on *D. farinae*, *E. maynei*, and *D. pteronyssinus*. Mites have been dipped in test solutions for various lengths of time and at various temperatures, permitted time to recover, and then examined for existence. Mite *D. farinae* has been noted to be the most sensitive to temperature and chlorine bleach among the

within 10 minutes, while most *E. maynei* and *D. pteronyssinus* stayed alive. But,

and *D. pteronyssinus*, respectively. Washing with cleansing agents at suggested and

C water alone, 100% death of *D. farinae* has been found

C has been required to destroy all *E. maynei*

**288**

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 [70]. 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 [71]. 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 [72]. Therefore, dust mites can be used as evidence in fields of forensic sciences.

#### **10. Conclusion**

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 *D. pteronyssinus* and *D. farinae* within Pyroglyphidae family. Unlike scabies mites or skin follicle mites, house dust mites do not burrow under skin and are not parasitic. Severe dust mites infestation in the home has been linked to atopic dermatitis, and epidermal barrier damage documented. Allergenic products of the common species of house dust mites are incompletely crossreacting, carrying both common and species-specific determinants. It is because of this a correct identification of the mite species is important. It is important to remember that as droppings of dead dust mites continue to provoke allergic reactions, it must be needed not only to reduce their populations but also take steps to remove their dead bodies and feces from homes. Allergy testing of a person can determine whether house dust mites trigger respiratory or dermatological symptoms. If tests show allergic to house dust mites, then reduce immune system response by undergoing allergen immunotherapy. A healthcare provider may recommend medicine to lessen the symptoms of dust mite allergies.

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

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**Author details**

Pakistan

Muhammad Sarwar

National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: drmsarwar64@gmail.com

provided the original work is properly cited.

*House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination*

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

*DOI: http://dx.doi.org/10.5772/intechopen.91891*

important evidence for elucidating of forensic cases.

#### *House Dust Mites: Ecology, Biology, Prevalence, Epidemiology and Elimination DOI: http://dx.doi.org/10.5772/intechopen.91891*

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.
