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.

A four-year-old sexually intact male dog and a seven-year-old sexually intact female dog presenting with heavy tick infestation were tentatively diagnosed with tick paralysis. Both dogs died due to respiratory failure. A number of ticks were observed in the head, ears, neck, trunk, and limbs of each dog. In these cases, a presumptive diagnosis of tick paralysis could be based on the presence of a species of tick known to cause paralysis combined with the absence of any other disease previously. Most ticks were identified as Haemaphysalis longicornis according to morphological features. Tick paralysis in dogs has rarely been reported in Korea.

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.

The acricidal potency of some essential oils can be applied to the control of house dust mites. But it is more effective keeping the house dust mites away than killing them because they remain as allergens even after death. The most efficient repellent concentration of lavender and tea tree in 10㎕ against house dust mites (Dermatophagoides farinae and D. pteronyssinus) were experimented by direct contact bioassay method at various doses ; 2.5, 1.25, 0.625, and 0.3125% and at vairous exposure times ; 15, 30, 60, 120, and 180 minutes. The most effective dose of essential oils (lavender and tea tree) against house dust were 0.625% and the repellent effectiveness at the mowt effective dose of 0.625% were 95.6% for lavander and 96.2% for tea tree, respectively. These results suggest that lavender and tee tree can be effectively used in the control of house dust mites.

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.