The effectiveness of benzyl benzoate and different chemicals as acaricides

Several observations have indicated that house-dust mites (HDM) play an important role in allergic diseases. Thus, the primary form of treatment should aim at reducing exposure to HDM for these patients. Allergen-avoidance measures in homes have been demonstrated to be beneficial in decreasing the risk of sensitization, severity of symptoms, bronchial reactivity, and basophil sensitivity. Various chemical methods, as well as physical measures, have been tried to eliminate mite allergens from house dust. However, none have gained wide acceptance because of the lack of effectiveness and safety, and the high cost. It is clear that new approaches are required for effective long-term control of HDM allergens. This study compared the acaricidal activities of phenyl salicylate, tea leaf extract (high tannic acid content), and essential oils (eucalyptus and laurel) with that of benzyl benzoate. The contact, short-duration persistence, and residual effects of various concentrations of these chemicals and benzyl benzoate were assessed in laboratory conditions with specially designed wells. Our data suggest that benzyl benzoate may not be effective when applied according to the manufacturer's instructions, but may be effective when applied more frequently (i.e., three to four times a year) and for longer periods (up to 24 h) even with lower concentrations (0.4%). Essential oils were shown to have little acaricidal activity, but virtually no effect was observed with tea. Among the chemicals used, phenyl salicylate seems to be promising as an alternative acaricide.     

Sensitization to house dust mites in Reykjavik, Iceland, in the absence of domestic exposure to mites

BACKGROUND: House dust mites are common sources of indoor allergens. In Reykjavik, Iceland, 9% of the young adult population had serum-specific IgE to Dermatophagoides pteronyssinus. Sensitization to mites is usually assumed to be due to exposure to house dust mites in the indoor environment. This investigation was carried out to measure the concentrations of house dust mite allergens and to investigate which species of mites were present in beds in Iceland. METHODS: A total of 197 randomly selected adults were visited at home using the European Community Respiratory Health Survey (ECRHS) II Indoor protocol. Dust samples were collected from mattresses for measurement of house dust mite allergen concentrations and to estimate the number and type of house dust mites. Additional samples from mattresses and floors were collected from the homes of 10 patients with positive skin prick tests (SPT) to D. pteronyssinus. House dust mite allergen concentrations were measured using ELISA and examination of mite species was carried out using microscopy. Climatic parameters were assessed using psychrometer readings in the bedrooms and outdoors. RESULTS: We found two single mite specimens, both D. pteronyssinus, in two dust samples. Mite allergen analyses indicated that two other dust samples had Der f 1 results close to the cut-off of 0.1 microg/g of dust. No samples were positive for Der p 1. In an additional collection of dust from the homes of 10 SPT-positive patients no Dermatophagoides spp. were found. CONCLUSIONS: Reykjavik citizens are exposed to extremely low amounts of house dust mite allergens in their homes. Possible alternative sources for sensitization are discussed, such as bird nests, exposure from travelling abroad, or other mites or invertebrates that cross-react with house dust mite allergens. Our findings suggest that exposures other than to house dust mites indoors are possible sources of mite allergen exposure.     

Identification of major allergens from the house dust mites, Dermatophagoides farinae and Dermatophagoides pteronyssinus, by electroblotting

The allergens were separated from the extracts of house dust mites by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and identified by autoradiography. Over 30 protein bands of the whole body extract of Dermatophagoides farinae were apparent on 10-20% gradient SDS-PAGE, and 13 bands with MW between 93KD and 12KD bound with specific IgE antibodies in patients' sera sensitive to house dust mites. The major allergenic component of the whole body extract of D. farinae was the protein of MW 14-15KD, which was detected in 95.7% of 47 patients' sera sensitive to house dust mites. The extract of Dermatophagoides pteronyssinus supplied by Bencard Company, England was thought to contain feces enriched material as noted in a few broad protein bands on SDS-PAGE. Seven allergenic components were shown by autoradiography. The protein band of MW 14-15KD was one of the most frequently revealed allergens on autoradiography, which has appeared in 32.5% of 40 patients' sera sensitive to house dust mites. The electrobotting technique used in the present study was fast, convenient and highly useful for both the identification of allergen components and the screening of specific IgE antibody. The individual variations of IgE immune responses to the allergenic components of the two house dust mites were discussed.     

Reduction of house dust mites and mite allergens: effects of spraying carpets and blankets with Allersearch DMS, an acaricide combined with an allergen reducing agent

Two studies were made to determine the acaricidal and allergen reducing properties of Allersearch DMS solution. In Study 1, samples of dust and carpet containing living mites were treated, in vitro, with DMS solution. No living mites were found in dust after 3-4 min or in carpets 50 min after treatment. In Study 2, mite counts and allergen estimation made on bed blankets before and after spraying with DMS solution showed a marked reduction in mite numbers (95%) and allergenicity (100-fold). Mite numbers and allergenicity stayed at this low level for 6 weeks. At 16 weeks both mites and allergens showed a slight increase, but were still significantly (P less than 0.001) below pretreatment levels.     

Biology, ecology, and prevalence of dust mites

The house dust mites D. farinae, D. pteronyssinus, and E. maynei are sources of multiple potent allergens in the indoor environment. They are common inhabitants in homes worldwide. Many biologically significant studies have revealed how well adapted these mites are to the microhabitats in homes. Ambient RH is a key factor in determining where these mites are found. Many aspects of the biology of house dust mites are not understood. A greater understanding of the biology of dust mites may reveal new strategies for controlling dust mites and their allergens in homes.     

Inhibition Experiments with Solid Phase Mite or Epithelia in House Dust Hypersensitivity

The present study was undertaken to verify that mites are not the only allergens in house dust extracts and that other allergens such as cat epithelia can also be responsible for house dust hypersensitivities detected both by house dust skin tests and house dust RAST studies. In order to determine whether mite or epithelia fixed on a solid phase could remove not only the IgE antibodies reactive with the homologous allergens, but also the IgE antibodies reactive with house dust allergens, the authors have absorbed 10 sera of house dust allergic patients with solid phase mite or epithelia. The absorption procedure removed a large part of the IgE antibodies reactive with specific immunosorbent (Dermatophagoides pteronyssinus or cat epithelia) and in the same way the IgE antibodies reactive with house dust immunosorbent. The percentage of RAST inhibition varied from 65% to 92% for Dermatophagoides pteronyssinus and from 65% to 94% for house dust in patients allergic to house dust and mite; the percentage of RAST inhibition varied from 67% to 92% for cat epithelia and from 73% to 90% for house dust in patients allergic to house dust and cat epithelia. This is in accordance with the hypothesis that house dust is not an allergen per se, but rather a complex mosaic of several allergens including mite, animal epithelia, etc.     

广州地区支气管哮喘患者常见吸入变应原调查分析

目的　调查广州地区支气管哮喘发病相关的主要致敏变应原 .方法　对 10 2例支气管哮喘缓解期患者 ,其中儿童 4 8例 ,成人 5 4例 ,用尘螨、霉菌、猫毛等 12种常见吸入变应原进行皮肤点刺试验 ,并测定其中 2 7例总IgE(TIgE)的水平 .结果　儿童组尘螨皮试阳性率最高 (均为 79.2 % ) ,其次是屋尘 (72 .9% ) .成年组尘螨皮试阳性率最高 ,粉尘螨和屋尘螨分别为 5 9.3%、6 2 .9% ,其次为屋尘 (4 0 .7% ) .在动物毛发皮屑中 ,以狗毛为主 ,猫毛次之 ;对于所有变应原 ,儿童组的阳性百分率远远高于成年组 ;2 7例血清总IgE的均值为 5 0 6 .1KU/L ,远高于正常人 ,其中皮试阳性者TIgE水平高于皮试阴性者 (p<0 .0 1) .结论　广州地区主要变应原均为尘螨 ,且哮喘儿童对尘螨过敏的阳性率显著高于成人     

Mite allergy and exposure to storage mites and house dust mites in farmers

Sensitization to house dust mites, storage mites and other common inhalation allergens was studied in 144 farmers using SPT and RAST. The study population was selected from a random sample of 808 farmers and consisted of 47 persons who had declared themselves to suffer from asthma, 63 persons who had reported respiratory symptoms, and 34 healthy persons without respiratory symptoms. The most prevalent RAST was towards storage mites and was found in 17% of farmers who suffered from asthma and was estimated to occur in 5% of the random sample of farmers. A positive RAST to house dust mites was found in 17% of farmers who reported to suffer from asthma. Sensitization to pollens, animal dander and grain species was rare. A positive RAST to moulds was not found. There was a strong association between a positive RAST to house dust mites and a positive RAST to storage mites (odds ratio 21.0). A positive RAST to storage mites was significantly associated with living in a dwelling in the past which was recalled as damp (odds ratio 4.9). A high number of house dust mites was found in nearly all dwellings (median count 148 mites/0.1 g dust) and a high number of storage mites was found in some dwellings. This study suggests that in humid and temperate regions of Europe, allergy to storage mites in farmers is not caused exclusively by occupational exposure but damp housing conditions and indoor exposure to storage mites may also be important.     

Allergy to storage mites in asthmatic patients and its relation to damp housing conditions

The relation between allergy to house dust mites and allergy to storage mites was studied in 326 patients with bronchial asthma. A positive RAST to house dust mites was found in 24.5% and to storage mites in 7.4%. There was a close association between a positive RAST to house dust mites and a positive RAST to storage mites, and 91.6% had a positive RAST to both. Only 0.9% with a negative RAST to house dust mites had a positive RAST to storage mites, whereas the frequency was 27.5% in those with a positive RAST to house dust mites. Present occupation with exposure to storage mites was found in 20.8% with a positive RAST to storage mites. A positive RAST to both house dust mites and storage mites was significantly associated with anamnestic indicators of damp housing conditions. The close association between allergy to house dust mites and allergy to storage mites in this study is probably caused by a common environmental factor, i.e. damp housing conditions.     

Benzyl benzoate moist powder: investigation of acaricidal [correction of acarical] activity in cultures and reduction of dust mite allergens in carpets.

Despite advances in the understanding of dust mites, it remains difficult to control exposure to mite allergens, and it is particularly difficult to reduce mites in fitted carpets or sofas. Several chemicals have been demonstrated to kill mites or denature mite allergens, and some of these chemicals have been investigated in carpets. Benzyl benzoate (BB), which has been widely used to kill scabies mites and is known to kill mites of the genus Dermatophagoides, has been used as a method of treating carpets. The present article describes experiments in the laboratory and in houses in testing two preparations of BB, a moist powder and a foam. The moist powder is composed of two ingredients, a wetted "inert" cellulose, which is designed to act as a cleaning agent, and the active BB adsorbed onto silicates. The active powder kills 90% of mites in culture within 12 hours and 100% in 24 hours, whereas the cellulose is not acaricidal. The moist-powder preparation was highly effective at killing D. farinae and D. pteronyssinus mites in the laboratory. In carpets the moist powder, applied for 12 hours with repeated brushing, was demonstrated to reduce the concentrations of group I and group II dust mite allergens in dust recovered at 1 month. This decrease in concentration could, in part, be explained by a persistent increased recovery of dust caused by residual white powder. However, when the recovery of group II allergens was calculated as the total allergen recovered, the decrease was highly significant at 2 weeks and 4 weeks after treatment (p less than 0.001). Application of the powder to carpets for 4 hours or of the foam to sofas was less effective. After 2 months the effect on mite antigen in carpets was still present, but some increase was apparent, suggesting that repeat application after 2 or 3 months would be necessary to control mite-allergen levels.     

The prevalence of allergy in Danish farmers

Sensitization to work-related and other common inhalation allergens was studied in 187 farmers by means of SPT and RAST. A positive RAST to house dust mites occurred in 6.4% and to storage mites in 5.3% of farmers. Sensitization to grain, pollen and animal dander was less frequent and a positive RAST to moulds was not found. There was a very strong association between a positive RAST to house dust mites and storage mites (odds ratio 173.6). Smoking seemed to be a risk factor for sensitization to mites, pollen, grain, and animal dander. Smokers who had lived in damp dwellings had a significantly increased risk of sensitization to mites (odds ratio 6.2-12.6), whereas this was not so with non-smokers (odds ratio 0.9-2.0).     

IgE-mediated occupational allergy to a spider mite

Two patients who suffered from allergic rhinitis, conjunctivitis and contact urticaria caused by the two-spotted spider mite (Tetranychus urticae, Koch) are described. Both patients worked in a greenhouse where they came in contact with both spider mites and predator mites living on bean leaves. Prick, Prausnitz-Küstner and RAST tests indicated type I allergy to spider mite but not to predator mite. Both patients had a high level (RAST score 4) of spider-mitE-specific IgE in their sera. Radioallergosorbent test (RAST) inhibition studies revealed no cross-reactivity between spider mite and house dust mite allergens. These results show that spider mites, which are herbivorous mites found in nature, in greenhouses and even in homes, can cause IgE-mediated allergy in man.     

The house dust mite Dermatophagoides pteronyssinus is the most important allergen on the island of Mauritius

To determine the relative importance of mites as a cause of allergic sensitivity and asthma on the western Indian Ocean island of Mauritius, we measured specific IgE antibodies to common inhalant allergens in sera from Mauritians claiming to have allergic symptoms and we examined house dust samples for evidence of mites and their allergens. Seventy-two of the 110 sera tested (65%) contained detectable IgE antibody to at least one mite, mould or pollen allergenic extract. By far the most prevalent was antibody to one or both of the common house dust mites, Dermatophagoides pteronyssinus and Dermatophagoides farinae, being present in 67 (61%) of the 110 sera. Allergy to pollens, including the locally prevalent Bermuda grass and sugar cane, was infrequent. Antibody to a limited number of moulds was detected in 22% of the sera tested. Of 81 subjects whose clinical history was known, 60 were asthmatic, and 75% of these asthmatic individuals had IgE antibody to mites. In contrast, only 35% of the subjects with rhinitis without asthma were sensitive to mites. Different mite species, including D. pteronyssinus but not D. farinae, were identified microscopically in samples of local house dust. Mite antigen Der p I but not antigen Der f I was detected with specific monoclonal antibodies in extracts of these dust samples. On the bases of this serological and environmental survey, we conclude that our data support the hypothesis that the house dust mite D. pteronyssinus is the principal cause of allergic sensitivity and asthma in that tropical environment.     

A study of skin test with regard to age differences and agreement with positive results from the RAST and ELISA methods]

Skin tests of the scratch type were performed on 132 asthmatic patients with 28 allergens. The threshold titers of skin test, RAST and ELISA of house dust, HD mites, Japanese cedar pollen, ragweed pollen and orchard grass pollen were included. The main skin-positive allergens among the patients were as follows: house dust, HD mites, Japanese cedar pollen, orchard grass pollen, timothy grass pollen and ragweed pollen. There are age differences on skin-positive rates among 4 age groups of the patients; 90% of the patients under 40 years old groups reacted positively to any of 28 allergens, while half number of the patients groups over 40 years old reacted positively to the allergens. According to the quantitative analysis between threshold titers of skin test and RAST titers using house dust and HD mites allergens, specific IgE production shall be decreased in the patients over 40 years old. Using 5 main allergens above mentioned, the agreements of positive responses between three methods were compared. RAST positive responses correlated well with the skin test results, while ELISA positive responses correlated rather poorly with the skin test results. However, correlation between RAST and ELISA results was relatively good. The correlation of positive responses to house dust and HD mites by the three methods was very good, but there were some cases where positive responses were obtained by only one of the methods.     

House dust mites in Iran

In the Caspian Sea region of Iran asthma seems closely related to house dust allergy. Since a high proportion of house dust sensitive patients appear to be sensitive to house dust mites, an investigation was carried out to determine the occurrence, distribution and abundance of these species in Iranian house dust in order to assess their role and clinical importance in house dust allergy in Iran. Thirty-five samples of house dust collected from houses in the Caspian Sea region and five samples from other areas were examined for mites. The three pyroglyphid species Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei, reported by European and Japanese workers to be common in house dust and to be a major source of house dust allergens, were found to occur in Iranian house dust and to account for nearly two-thirds of the total mite population present in the dust. Dermatophagoides pteronyssinus was the most frequent and most numerous species recorded, occurring in 90% of the samples examined and forming 94% of the pyroglyphid and 60% of the total mite population. The frequency with which house dust mites were found in the Iranian Caspian Sea region coupled with the relatively high frequency of allergic bronchial asthma in this area suggests that they may well be an important precipitating factor in asthma in Iran.     

Age-dependent tendency to become sensitized to other classes of aeroallergens in atopic asthmatic children.

BACKGROUND: Several longitudinal studies report that allergic sensitization increases with age from childhood to adulthood. OBJECTIVE: To evaluate whether an age-dependent tendency to become sensitized to new classes of allergens is present in atopic children, we studied retrospectively the changes in allergic sensitization in 165 asthmatic patients, monosensitized (ie, sensitized to only one class of allergens) in the first survey. METHODS: All the children (18 months to 8 years at enrollment), attended our outpatient clinics twice, at time intervals ranging from 2 to 10 years. On each visit, sensitization to house dust mites, pollens, animal danders, and molds was determined by skin prick test. RESULTS: We found that 43.6% (n = 72) of the patients became polysensitized on the second survey. According to age on first survey, the patients were further divided into two age groups: (1) group 1 = 18 months to < 5 years old (n = 98) and (2) group 2 = 5 to 8 years (n = 67). The transition from monosensitization to polysensitization observed in the entire population was present in both groups: 47 (47.9%) of the 98 children in group 1 and 25 (37.3%) of the 67 children in group 2 showed to be sensitized to more classes of allergens, as compared with first survey. Both in the whole population and in the two age subgroups, the changes in the frequency of monosensitization between the two evaluations were time-dependent (P < .05, each Chi(2)). Finally, to investigate whether monosensitization to a specific class of allergens could favor the development of polysensitization, we evaluated the frequency of polysensitization in the second survey in patients originally monosensitized to house dust mites or to pollens. We found that of the 130 patients originally monosensitized to house dust mites, 59 became polysensitized (45.4%), while of the 28 patients originally monosensitized to pollens, 9 became polysensitized (32.1%) (P > . 1). Similar results were obtained when patients were divided into age groups. CONCLUSION: These data demonstrate that (1) monosensitized children are likely to become polysensitized and (2) house dust mite sensitization and, at a lower degree, pollen sensitization, apparently seem to play a "triggering" role in the development of polysensitization, since a high proportion of children originally monosensitized to house dust mites or to pollens became polysensitized.     

Prevalence of specific IgE to storage mites (A. siro, L. destructor and T. longior) in an urban population and crossreactivity with the house dust mite (D. pteronyssinus)

The role of pyroglyphid mites in house dust allergy is well established and the major allergens from the common house dust mites (Dermatophagoides species) have been characterized. There is, however, relatively little progress in the understanding of the human IgE response to non-pyroglyphid storage mites, allergenic crossreactivity with other mite species and extent of environmental exposure. We studied 196 individuals from an urban environment who were not occupationally exposed to storage mites and found a 24% prevalence of specific IgE antibody to Dermatophagoides pteronyssinus and a 14% prevalence of RAST positivity to at least one of three storage mites, Acarus siro, Lepidoglyphus destructor and Tyrophagus longior. All individuals with a positive RAST to storage mites had specific IgE to D. pteronyssinus. RAST inhibition studies with the eight sera with greater than 2% RAST binding to both families of mites showed considerable crossreactivity between D. pteronyssinus and the storage mites A. siro and T. longior and limited crossreactivity between D. pteronyssinus and L. destructor. This suggests that at least some of the response to storage mites observed by direct RAST is a consequence of crossreactivity with the more abundant D. pteronyssinus.     

Relationship between the clinical course of bronchial asthma from childhood to adulthood (deterioration/improvement), bronchial hyperreactivity and incidence of house dust mite allergens in households of persons treated for atopic bronchial asthma as children

The aim of the study was to determine the impact of the exposition to house dust mite allergens or its lack on clinical state of asthma in young adults treated in their childhood for atopic bronchial asthma. The concentration of house mite allergen was studied with the method of Acarex test (detection of guanine--excretory product of house dust mites) in the flats of 55 persons treated for atopic asthma before adolescence. There was significant difference (p < 0.006) between the clinical course of asthma (improvement) in persons living in flats free of house dust mite allergens and those living in flats infested with mites. House dust mite allergens were present significantly more frequently in flats of persons with a low histamine threshold (19 of 20 examined flats) than in flats of persons with a high histamine threshold or without hyperreactivity to histamine (6 of 20 examined flats).     

Eliminating Dermatophagoides farinae spp. (Acari: Pyroglyphidae) and their allergens through high temperature treatment of textiles

House dust mite allergens cause allergy and asthma in sensitized individuals. The allergens they produce are known to resist decay under natural household conditions and are thought to accumulate until removed. We sought to evaluate the effects of high temperature (96 degrees C) generated by a hard surface cleaner on live mite populations of American house dust mites, Dermatophagoides farinae Hughes and their allergens in carpet and mattresses. Statistically significant (P < 0.05) mite mortality (100%) was observed in response to treatment in both textile surfaces. Similar effects were observed on Der f1 fecal allergen. Allergen reductions in carpet with two or five pass treatment regimes were 61.4 and 100%, respectively. These results demonstrate the potential of employing a hard surface steam cleaner as a novel method to eliminate house dust mite populations and their allergens in a residential setting and appeal particularly promising as an environmental control strategy.     

Spider-mite allergy and asthma in fruit growers

Asthma and allergic diseases caused by domestic mites such as house dust mites and storage mites are major health problems worldwide. In contrast to domestic mites, spider mites are outdoor phytophagous mites causing significant damage to fruit leaves throughout the world. After several case reports of spider mite-induced asthma and allergy, cross-sectional surveys have demonstrated that spider mites are important allergens in the development of asthma and rhinitis in fruit farmers. Interestingly, epidemiological surveys have also demonstrated that spider mites are common sensitizing allergens that are related to the prevalence of asthma and rhinitis, even in the non-farming population exposed to spider mites. Protein analysis has demonstrated that crude extracts derived from spider mites contain several major allergens, and that N-terminal amino acid sequencing of the major allergens is not homologous with any previously characterized domestic mite allergens, suggesting that major allergens derived from spider mites are unique in terms of cross-reactivity to domestic mites. Taken together, these findings suggest that spider mites are important allergens in the development of asthma among the exposed non-farming population as well as among fruit farmers themselves, and that allergens derived from spider mites may be novel allergens.