Exposure to house dust mites is closely connected with allergic diseases such as atopic dermatitis, allergic rhinitis, and asthma. House dust mites (Dermatophagoides farinae and D. pteronyssinus) act as allergens even after their death. Therefore, repelling the house dust mites is more effective method than killing them. Many chemical agents have been used in killing house dust mite. However, it is usually reported that these chemical agents (acaricides) exhibit adverse effects and toxicity toward animals and human. For these reasons, we carried out the experiments for measuring the repellent activity of Mate tea and Jasmine tea against house dust mites in this experiment. In order to determine the concentration having the most effective repellent effect of Mate and Jasmine tea, house dust mites (D. farinae and D. pteronyssinus) were exposed at different concentrations (0, 0.015625, 0.03125, 0.0625, 0.125, 0.25, 0.5 mg/40 μL) of Mate tea and Jasmine tea extracts, respectively, for different hours (0.5, 1, 2, 3 hours). The most effective repellent effect (%) against house dust mite in 0.25 mg/40 μL of Mate tea for 2 hours was 73.5%, Jasmine Petal tea in 0.0625 mg/40 μL for 1 hour was 84.1% and Pearl Jasmine tea in 0.125 mg/40 μL for 0.5 hour was 82.8%. These results suggest that Mate tea and Jasmine tea extracts have potential effect to repel the house dust mites (D. farinae and D. pteronyssinus)

The gingival epithelium of the oral cavity is constantly exposed to exogenous stimuli such as bacterial toxins, allergens, and thermal changes. These exogenous stimuli are resisted by innate host defense in gingival epithelial cells. However, it is unclear exactly how the exogenous stimuli affect detrimentally on the human gingival epithelial cells. Here, we investigated whether the allergen, such as house dust mite (HDM) extract, is linked to Ca2+ signaling and proinflammatory cytokine expression in primary cultured human gingival epithelial cells. HDM extract induced an increase in intracellular Ca2+ concentration ([Ca2+]i) in a dose-dependent manner. Extracellular Ca2+ depletion did not affected on the HDM extract-induced increase in [Ca2+]i. The HDM extractinduced increase in [Ca2+]i was abolished by the treatment with U73122 and 2-APB, which are inhibitors of phospholipase C (PLC) and inositol 1,4,5-trisphosphate (IP3) receptor. Moreover, HDM extract induced the mRNA expression of pro-inflammatory cytokine, interleukin (IL)-8. These results suggest that HDM extract triggers PLC/IP3-dependent Ca2+ signaling and IL-8 mRNA expression in primary cultured human gingival epithelial cells.

An assessment was made of the toxicity of hiba, Thujopsis dolabrata var. hondai, oil and 24 oil constituents and control efficacy of four experimental spray formulations containing the oil (0.5. 1, 2, and 3% sprays) to adult American house dust mite (AHDM), Dermatophagoides farinae, and copra mite (CM), Tyrophagus putrescentiae. Results were compared with those of three conventional acaricides benzyl benzoate, N,N-diethyl-3-methylbenzamide (deet), and permethrin. Based on 24 h LC50 values, (–)-thujopsene was the most toxic constituent against AHDM (9.82 μg/cm2) and CM (10.92 μg/cm2) and the toxicity of the compound was nearly identical to that of benzyl benzoate (9.33 and 10.14 μg/cm2). High toxicity was also observed with (–)-(E)-pinocarveol, carvacrol, (+)-terpinen-4-ol, β-thujaplicin, cedrol, α-terpineol, (+)-ledene, thymol, and 2,4-di-tert-butylphenol against both mite species (LC50, 11.92–19.19 and 12.49–22.97 μg/cm2). These constituents were more toxic than deet (LC50, 35.53 and 38.42 μg/cm2). Hiba applied as 2 and 3% sprays provided >95% mortality against both mite species, whereas permethrin (cis:trans, 25:75) 2.5 g/L spray treatment resulted in ca 11% mortality. Global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments justify further studies on hiba oil preparations containing the constituents described as potential contact-action fumigants or lead molecules for the control of mite populations.

House dust mite (HDM) allergens have been associated with allergic diseases, such as asthma, allergic rhinitis, and atopic dermatitis. Various acaricidal agents have been suggested for control of house dust mites; however, their remains act as allergens even after death. Therefore, for avoidance of allergen, expelling the mites is a more effective policy than killing them. In this experiment, we compared the repellent effect of two essential oils (Matricaria chamomilla, Lavandula vera) against house dust mites, Dermatophagoids farinae and D. pteronyssinus in bed fabric. The essential oils were applied by direct contact method at various doses (0.1, 0.05, 0.025, 0.0125, and 0.00625 μl/cm2 and at various exposure times (30, 60, 120, 180, and 240 min). Results of this experiment suggest that the two oils have significant repellent activity. Camomile essential oil in 0.0125 μl/cm2 at 240 minutes had a repellent effect of 93.7% and lavender essential oil in 0.05 μl/cm2 at 180 minutes had a repellent effect of 88.9%. The results of this study showed that camomile essential oil has more potent repellent activity than lavender essential oil at a particular concentration.

House dust mites (HDMs) play an important role in the occurrence of allergic diseases such as asthma and atopic dermatitis. Dermatophagoides pteronyssinus (Der p) is one of the most prevalent HDMs. It mediates the activation of T cells and monocytes, and induces the elevation of immunoglobulin E levels in allergic diseases. However, the effects of Der p on human monocytes have not been fully understood. In the present study, we investigated whether or not Der p has a great effect on the chemotactic activity of the human monocytic cell line, THP-1 cells, as induced by CC chemokines. We also show that the Der p extract (DpE) increased the chemotactic activity of THP-1 cells in response to MCP-1, RANTES, MIP-1α, and TARC, but has no effect on the expressions of CC chemokine receptors (CCRs) binding to CC chemokines in THP-1 cells. Protease inhibitors, such as aprotinin and E64, blocked the increased chemotaxis, while cytoplasmic Ca2+ influx mediated by these chemokines was inhibited by DpE. These results indicate that DpE increases the chemotactic activity of THP-1 cells in response to CC chemokines by regulating the cells’ protease-dependent mechanism. This finding may be useful in identifying the pathogenesis of allergic diseases induced by Der p.

Various acaricidal agents have been used to reduce the dust mite population. On the point of keeping people away from mite allergens, however, repelling mites from the living space of human is more effective than just killing them, because the dead bodies of mites still act as allergen. To examine the potential of Artemisia in controling house dust mites, Artemisia extract was evaluated for its repellency to Dermatophagoides farinae and D. pteronyssinus. Repellency tests were performed using filter-paper circles cut in halves. The Artemisia extract was applied on each half at concentrations of 0, 0.1, 0.2, 0.4 and 0.8㎕/㎠. Proper repellent effects of Artemisia extract on house dust mites were observed at the concentrations of ＞0.4㎕/㎠. As a positive control, lavender essential oil was used at concentrations of 0, 0.0125, 0.025, 0.05 and 0.1㎕/㎠. Lavender oil showed proper repellent effects at concentrations of ＞0.05㎕/㎠. These results suggest that Artemisia extract has potential to control the house dust mites, and might be useful as a dust mite repellent.

Dyed loess and charcoal fabrics are sold in market as bedding. They have a lot of functions so that people are getting to increase their expenditure for them. Thus we investigated a repellent effect of loess fabrics and charcoal fabrics against house dust mites. The evaluation of the repellent effect of dyed loess fabrics and charcoal fabrics was conducted by using Dermatophagoides farinae and D. pteronyssinus. We compared the repellent effect of dyed loess fabrics at different doses of 0.3, 1.0, 3.2, 10.0 ㎎/㎠ and dyed charcoal fabrics at different doses of 0.3, 0.6, 1.0 ㎎/㎠. Commercial loess fabrics did not have a repellent effect against house dust mites. but commercial charcoal fabrics had the repellent effect by 78% against them. In case of dyed charcoal fabrics added with charcoal powder over 0.6 ㎎/㎠, they showed the repellent effect by over 80%. These results suggest that loess fabrics and charcoal fabrics have a repellent effect of against house dust mites and they can be commercially used for the purpose.

House dust mite of the indoor environment is one of the most important causes of allergic asthma and rhinitis. It has been known that more than 70% of Korean children and about 50% of adult with the respiratory allergy are sensitive to house dust mite. The purpose of our study is to find out the relationship between the concentration of formaldehyde (HCHO)/PM10 and the number of house dust mite in the indoor environment. In this study, sampling sites were education, social and dwelling facilities. We inquire the questionnaire of the resident on the indoor air quality in all sampling sites. At the same time, we measured the concentration of formaldeh yde(HCHO)/PM10 as well as house dust mites. it was complained by 20% respondents that the indoor air quality was bad and by 10% that the atopy symptom was evident. When a certain amount of house dust mites were detected, the contents of PM10 were observed high and that of HCHO low. However when the house dust mites were not detected, the concentration of PM10 was low and that of HCHO high. From our results, it is concluded that the indoor air quality (i.e. conc. of PM10/HCHO) is quite related to the contents of house dust mites supporting the fact that the symptom of atopy and asthma is due to these small organisms.

The insecticidal potency of some essential oils have been suggested that they may find an application in the control of house dust mites. We compared the repellent effect of four essential oils ; lemon grass (Cymbopogon nardus), lavender(Lavandula vera), rosemary(Rosmarinus officinalis) and ylang ylang(Cananga odorata). The oils were exposed at different doses(0.1, 0.05, 0.025, 0.0125, and 0.00652 ㎕/㎠) and different times(1, 2, 3, 4, 5 hours) on house dust mites(Dermatophagoides farinae and D. pteronyssinus). The repellent effects(%) of essential oils that were exposed at 0.1 ㎕/㎠ and for 1 hours against house dust mites were lemon grass(63.3%) and rosemary(61%), lavender(40%), ylang ylang(40%) in the order named.