The control of allergens of dust mites and domestic pets: a position paper

Indoor air quality in remote first nations communities in Ontario, Canada

A recent study of the health of Indigenous children in four First Nations Communities in remote northwestern Ontario found that 21% of children had been admitted to hospital for respiratory infections before age 2 years. Here we report a detailed analysis of the housing conditions in these communities. We employed a variety of statistical methods, including linear regression, mixed models, and logistic regression, to assess the correlations between housing conditions and loadings of biocontaminants (dust mite allergens, fungal glucan, and endotoxin) and indoor concentrations of PM2.5, CO2, benzene, and formaldehyde. The houses (n = 101) were crowded with an average of approximately 7 people. Approximately 27% of the homes had sustained CO2 concentrations above 1500 ppm. Most homes had more than one smoker. Commercial tobacco smoking and the use of non-electric heating (e.g., wood, oil) were associated with increased fine particle concentrations. Over 90% of the homes lacked working Heat Recovery Ventilators (HRVs), which was associated with increased fine particle concentrations and higher CO2. Of the 101 homes, 12 had mold damage sufficient to increase the relative risk of respiratory disease. This resulted from roof leaks, through walls or around the windows due to construction defects or lack of maintenance. A similar percentage had mold resulting from condensation on windows. Endotoxin loadings were much higher than any previous study in Canada. This work provides evidence for the need for more effort to repair existing houses and to ensure the HRVs are properly installed and maintained.

Climatotherapy for asthma: Research progress and prospect

Asthma affects over 300 million people globally and is a cause of substantial burden of disease, including both premature death and reduced quality of life in people of all ages. Although both genetic and environmental factors play an important role in the pathogenesis of asthma, the rising trend of asthma and other allergic diseases over recent decades is thought to be largely caused by alteration in environmental conditions. Thus, a considerable amount of attention has been paid to environmental modification for the treatment and management of asthma, including household allergen reduction and/or irritant removal. More advanced environmental modification strategies (e.g., health resort medical rehabilitation, high-altitude climate therapy and multiple-hit interventions) have also been suggested. Research advances have been made over the past decades, but major challenges and opportunities coexist in this emerging field. Concerted efforts are required to tackle these formidable challenges.

Comparative Genomics Reveals Insights into the Divergent Evolution of Astigmatic Mites and Household Pest Adaptations

Highly diversified astigmatic mites comprise many medically important human household pests such as house dust mites causing ∼1–2% of all allergic diseases globally; however, their evolutionary origin and diverse lifestyles including reversible parasitism have not been illustrated at the genomic level, which hampers allergy prevention and our exploration of these household pests. Using six high-quality assembled and annotated genomes, this study not only refuted the monophyly of mites and ticks, but also thoroughly explored the divergence of Acariformes and the diversification of astigmatic mites. In monophyletic Acariformes, Prostigmata known as notorious plant pests first evolved, and then rapidly evolving Astigmata diverged from soil oribatid mites. Within astigmatic mites, a wide range of gene families rapidly expanded via tandem gene duplications, including ionotropic glutamate receptors, triacylglycerol lipases, serine proteases and UDP glucuronosyltransferases. Gene diversification after tandem duplications provides many genetic resources for adaptation to sensing environmental signals, digestion, and detoxification in rapidly changing household environments. Many gene decay events only occurred in the skin-burrowing parasitic mite Sarcoptes scabiei. Throughout the evolution of Acariformes, massive horizontal gene transfer events occurred in gene families such as UDP glucuronosyltransferases and several important fungal cell wall lytic enzymes, which enable detoxification and digestive functions and provide perfect drug targets for pest control. This comparative study sheds light on the divergent evolution and quick adaptation to human household environments of astigmatic mites and provides insights into the genetic adaptations and even control of human household pests.

Household determinants of biocontaminant exposures in Canadian homes

Exposure to biocontaminants, such as dust mites, animal dander, bacteria, and mold, is associated with a range of health effects. This study identified household characteristics associated with indoor biocontaminant loadings in four Canadian cities. Floor dust was collected in 290 Canadian homes in Edmonton, Halifax, Montreal, and Windsor. The dust samples were analyzed for house dust mite allergens (Der f 1 and Der p 1), cat allergen (Fel d 1), cockroach allergen (Bla g 1), beta-(1,3)-D-glucan, and endotoxin. Household information was obtained through questionnaires and home inspections. We performed univariate and multivariate analyses to identify household determinants of biocontaminant loadings and mold odor presence. We observed large regional variations for all biocontaminants, except for cockroach allergen. The ranges of the contaminants measured in loadings and concentrations were similar to that of previous Canadian studies. Household characteristics including presence of carpeting, low floor cleaning frequency, older home age, presence of pets, and indoor relative humidity above 45% were positively associated with the presence of multiple indoor biocontaminants. High floor cleaning frequency and use of dehumidifiers were negatively associated with the presence of multiple indoor biocontaminants. Mold odor was positively associated with older home age, past water damage, and visible mold growth.

BSACI guideline for the diagnosis and management of allergic and non-allergic rhinitis (Revised Edition 2017; First edition 2007)

This is an updated guideline for the diagnosis and management of allergic and non-allergic rhinitis, first published in 2007. It was produced by the Standards of Care Committee of the British Society of Allergy and Clinical Immunology, using accredited methods. Allergic rhinitis is common and affects 10-15% of children and 26% of adults in the UK, it affects quality of life, school and work attendance, and is a risk factor for development of asthma. Allergic rhinitis is diagnosed by history and examination, supported by specific allergy tests. Topical nasal corticosteroids are the treatment of choice for moderate to severe disease. Combination therapy with intranasal corticosteroid plus intranasal antihistamine is more effective than either alone and provides second line treatment for those with rhinitis poorly controlled on monotherapy. Immunotherapy is highly effective when the specific allergen is the responsible driver for the symptoms. Treatment of rhinitis is associated with benefits for asthma. Non-allergic rhinitis also is a risk factor for the development of asthma and may be eosinophilic and steroid-responsive or neurogenic and non- inflammatory. Non-allergic rhinitis may be a presenting complaint for systemic disorders such as granulomatous or eosinophilic polyangiitis, and sarcoidoisis. Infective rhinitis can be caused by viruses, and less commonly by bacteria, fungi and protozoa.

How clean is your house? A study of house dust mites, allergens and other contents of dust samples collected from households

Household dust contains an array of constituents, including house dust mites (HDM) and the HDM allergen, Der p 1, which can cause sensitivities such as asthma and eczema. Vacuuming can help alleviate symptoms, yet little is understood about cleaning behaviour in different households. This pilot study investigated the contents of dust from four household types (students; over 65 s; and families with and without pets). This was then related to cleaning behaviours and perceptions of cleanliness. Our investigation found that HDMs and Der p 1 were present in all households and sampling locations, including participants' cars. The median Der p 1 was greatest in the living room, though results varied. Demographic group was a determinant for the number of human and pet hairs present in dust. Surprisingly, vacuuming was the most disliked task overall. This information requires consideration when developing cleaning products and advising individuals with dust-related health issues.

Indoor Environmental Control Practices and Asthma Management

Indoor environmental exposures, particularly allergens and pollutants, are major contributors to asthma morbidity in children; environmental control practices aimed at reducing these exposures are an integral component of asthma management. Some individually tailored environmental control practices that have been shown to reduce asthma symptoms and exacerbations are similar in efficacy and cost to controller medications. As a part of developing tailored strategies regarding environmental control measures, an environmental history can be obtained to evaluate the key indoor environmental exposures that are known to trigger asthma symptoms and exacerbations, including both indoor pollutants and allergens. An environmental history includes questions regarding the presence of pets or pests or evidence of pests in the home, as well as knowledge regarding whether the climatic characteristics in the community favor dust mites. In addition, the history focuses on sources of indoor air pollution, including the presence of smokers who live in the home or care for children and the use of gas stoves and appliances in the home. Serum allergen-specific immunoglobulin E antibody tests can be performed or the patient can be referred for allergy skin testing to identify indoor allergens that are most likely to be clinically relevant. Environmental control strategies are tailored to each potentially relevant indoor exposure and are based on knowledge of the sources and underlying characteristics of the exposure. Strategies include source removal, source control, and mitigation strategies, such as high-efficiency particulate air purifiers and allergen-proof mattress and pillow encasements, as well as education, which can be delivered by primary care pediatricians, allergists, pediatric pulmonologists, other health care workers, or community health workers trained in asthma environmental control and asthma education.

Effective allergen avoidance for reducing exposure to house dust mite allergens and improving disease management in adult atopic asthmatics

OBJECTIVE

We investigated the best strategy for adult asthmatics to avoid exposure to Dermatophagoides group (Der-1) allergens.

METHODS

Adult atopic asthmatics (n = 111) followed a 32-item checklist for avoiding Der-1 allergen exposure. Twenty-five patients were excluded through incomplete sampling; 50 remaining patients encased their pillows/futons/mattresses in microfine-fiber covers, 13 used vacuum cleaners with dust-mite-collection nozzles, and 23 acted as non-intervention controls. During August-October 2010 and August-October 2011, dust samples were collected in Petri dishes placed in bedrooms for 2 weeks and from mattresses/futons by using adhesive tape on one morning. A Der-1 level decrease was defined as a mean 2011 Der-1 level of <1 as a ratio of the 2010 level on tape or Petri dish samples. We analyzed the associations between Der-1 level change (by ELISA) and % weekly variability in peak expiratory flow (PEF) or fraction of exhaled nitric oxide (FeNO) after intervention.

RESULTS

Der-1 levels decreased significantly in the covers group but not the vacuuming group. FeNO levels and PEF variability were unchanged in both groups. In patients whose Petri dish or tape samples showed decreased Der-1 levels, the % PEF variability was lower in 2011 than in 2010, but FeNO levels were unchanged. Three interventions (vacuuming all family members' mattress/futon surfaces at least weekly or after exposure of the futons to sunlight, and floor wiping before vacuuming), plus using covers, were the most effective management strategy in reducing Der-1 levels.

CONCLUSIONS

This environmental and bedding maintenance program may help manage adult atopic asthma.

Studies on the Occurrence, Identification and Control of House Dust Mites at Rural Houses of Shebin El-Kom Locality, Egypt

The present study was conducted at Elkom Elakhdar village, Shebin El-Kom, Menoufia Governorate along 2012 year seasons, to calculate and identify the species composition and the occurrence frequency of the extracted dust mites collected from three building ages at rural houses, as well as to determine the toxicity limits of different concentrations of three plant essential oils against two species of the family Pyroglyphidae the main causal of allergy to humans. The obtained results revealed that there were eleven mite species belong to five families (Pyroglyphidae, Chortoglyphidae, Glycyphagidae, Acaridae and Cheyletidae). Of the total collected mites (5276) the highest dominant percentage species was the dust mites: Dermatophagoides farinae (66.1%), followed by D. pteronyssinus (23.3%), while the percentages of the rest species: Chortoglyphus arcuatus, Lepidoglyphus destructor, Glycyphagus domesticus, Gohieria fusca, Tyrophagusputrescentiae, Caloglyphus sp, Cheyletus malaccensis, Blomia sp. and Acarus siro were ranged between 0.16-2.0%. Regarding to the effect of temperature degrees on mite population, high degrees more than 25 degrees C at summer season, decreased the numbers of D. farinae and D. pteronyssinus. Toxicological tests of the three plant essential oils against adult stages of D. farinae and D. pteronyssinus showed that lemon grass oil gave the highest toxicity effect, in comparison with geranium and thyme oils, where mortality percentages were approximately around 100% at 800 ppm concentration on both species. The LC50 of lemon grass were 228.992 and 293.615 ppm against the two species, respectively. From the results of the research, it could be recommend that it is preferable to apply control operation during summer season where the mite population density is the least, moreover, the botanical oil extracts effectively controlled the parasitic dust mites, D. farinae and D. pteronyssinus and can be used in the biological control programs, as well as, it can play effective role in the integrated management programs.

Do questions reflecting indoor air pollutant exposure from a questionnaire predict direct measure of exposure in owner-occupied houses?

Home characteristic questions are used in epidemiological studies and clinical settings to assess potentially harmful exposures in the home. The objective of this study was to determine whether questionnaire-reported home characteristics can predict directly measured pollutants. Sixty home inspections were conducted on a subsample of the 2006 population-based Toronto Child Health Evaluation Questionnaire. Indoor/outdoor air and settled dust samples were analyzed. Mean Fel d 1 was higher (p < 0.0001) in homes with a cat (450.58 μg/g) versus without (22.28 μg/g). Mean indoor NO(2) was higher (p = 0.003) in homes with gas stoves (14.98 ppb) versus without (8.31 ppb). Self-reported musty odours predicted higher glucan levels (10554.37 μg/g versus 6308.58 μg/g, p = 0.0077). Der f 1 was predicted by the home's age, but not by reports of carpets, and was higher in homes with mean relative humidity > 50% (61.30 μg/g, versus 6.24 μg/g, p = 0.002). Self-reported presence of a cat, a gas stove, musty odours, mice, and the home's age and indoor relative humidity over 50% predicted measured indoor levels of cat allergens, NO(2), fungal glucan, mouse allergens and dust mite allergens, respectively. These results are helpful for understanding the significance of indoor exposures ascertained by self-reporting in large epidemiological studies and also in the clinical setting.

Indoor mites and forensic acarology

House dust mites (HDM) have been shown to produce allergens causing atopic allergies in human beings, known in medicine as house-dust-mite allergy or atopy. Over the past 25 years (1981-2006) a survey of dust samples from different places was made in the southern part of Poland, to determine the diversity of indoor acarofauna. In total, 1,532 samples were taken from dwellings, hospitals, libraries, research laboratories, drug-stores, and offices and other workplaces. More than 30 mite species were found of which the most abundant and common were HDM, especially Dermatophagoides farinae. Highest mite densities (g(-1) dust) were noted in dwellings. This survey revealed differences in the occurrence and prevalence of various species of domestic mites between and within (dwellings in) geographical areas. This knowledge may be useful in the field of forensic medicine.

Transition matrix population model for dust mite Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

A transition matrix model of the population dynamics of the European house dust mite, Dermatophagoides pteronyssinus (Trouessart) (Acari: Pyroglyphidae), is described. It can model continuously varying conditions by forming transition matrices by interpolation between known transition matrices constructed from experimental data. Finite carrying capacity is modeled by modifying the population distribution vector at each time-step by using a form of the Skellam model, which is derived from the assumption that in competition each successful animal gets all it requires, and the unsuccessful animals get insufficient resources for survival or reproduction. The transition matrix model does not require all mites to have the same survivorship, life-stage durations, fecundity, and so on. Life table data to drive the model is taken from two sources, one source of which requires using the mean and standard deviation of the duration of each stage to synthesize a range of duration times and a range of transition probabilities to the next stage, thus ensuring variability between mites. Where synthesized data are used, significant long-lasting oscillations in dust mite levels are modeled, which does not happen when modeling with unsynthesized data, and is unlikely to occur in the field. Under conditions normally met with in the microenvironment (bedding, base of carpet, soft furnishing) of D. pteronyssinus, finite carrying capacity is essential to prevent unbounded population growth. The model is compared with other workers' field data with fair agreement. It is argued that shortcomings in the available data rather than the model are the principal reasons for differences between field and modeled results.

Limonene - a Review: Biosynthetic, Ecological and Pharmacological Relevance

Limonene is one of the most common compounds found in the essential oils of aromatic plants. The occurrence of this monoterpene hydrocarbon in various plant genera could be attributed to its precursory role in the biosynthesis of other monoterpenes and its defensive role against herbivores. Due to the medicinal potential and application in the flavor and fragrance industries, limonene has been extensively investigated. In this paper the biosynthetic, ecological and pharmacological importance of limonene is presented in an attempt to coherently summarize some of the most salient aspects from various studies in a form of a concise review.

House dust mite control measures for asthma

EDITORIAL NOTE

This 2011 review predates current reporting standards and methodological expectations for Cochrane Reviews. It should not be used for clinical decision‐making.

BACKGROUND

The major allergen in house dust comes from mites. Chemical, physical and combined methods of reducing mite allergen levels are intended to reduce asthma symptoms in people who are sensitive to house dust mites.

OBJECTIVES

To assess the effects of reducing exposure to house dust mite antigens in the homes of people with mite-sensitive asthma.

SEARCH STRATEGY

PubMed and The Cochrane Library (last searches Nov 2007), reference lists.

SELECTION CRITERIA

Randomised trials of mite control measures vs placebo or no treatment in people with asthma known to be sensitive to house dust mites.

DATA COLLECTION AND ANALYSIS

Two authors applied the trial inclusion criteria and evaluated the data. Trial authors were contacted to clarify information.

MAIN RESULTS

Fifty-four trials (3002 patients) were included. Thirty-six trials assessed physical methods (26 mattress encasings), 10 chemical methods, and 8 a combination of chemical and physical methods. Despite the fact that many trials were of poor quality and would be expected to exaggerate the reported effect, we did not find an effect of the interventions. For the most frequently reported outcome, peak flow in the morning (1565 patients), the standardised mean difference was 0.00 (95% confidence interval (CI) -0.10 to 0.10). There were no statistically significant differences either in number of patients improved (relative risk 1.01, 95% CI 0.80 to 1.27), asthma symptom scores (standardised mean difference -0.04, 95% CI -0.15 to 0.07), or in medication usage (standardised mean difference -0.06, 95% CI -0.18 to 0.07).

AUTHORS' CONCLUSIONS

Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot be recommended. It is doubtful whether further studies, similar to the ones in our review, are worthwhile. If other types of studies are considered, they should be methodologically rigorous and use other methods than those used so far, with careful monitoring of mite exposure and relevant clinical outcomes.

BSACI guidelines for the management of allergic and non-allergic rhinitis

This guidance for the management of patients with allergic and non-allergic rhinitis has been prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is for use by both adult physicians and paediatricians practicing in allergy. The recommendations are evidence graded. During the development of these guidelines, all BSACI members were included in the consultation process using a web-based system. Their comments and suggestions were carefully considered by the SOCC. Where evidence was lacking, consensus was reached by the experts on the committee. Included in this guideline are clinical classification of rhinitis, aetiology, diagnosis, investigations and management including subcutaneous and sublingual immunotherapy. There are also special sections for children, co-morbid associations and pregnancy. Finally, we have made recommendations for potential areas of future research.

Sublingual immunotherapy with a standardized cat dander extract: evaluation of efficacy in a double blind placebo controlled study

BACKGROUND

Little information is available on the clinical efficacy of sublingual immunotherapy (SLIT) using extracts derived from mammalian epithelia.

OBJECTIVES

To assess clinical efficacy of cat SLIT based on natural exposure challenge test (NCT).

MATERIAL AND METHODS

Fifty cat allergic patients with rhinoconjunctivitis with or without asthma were included in a randomized double blind placebo controlled clinical trial of cat SLIT during 1 year. Twenty-five patients received active treatment and 25 placebo. Sublingual immunotherapy efficacy was assessed by natural exposure challenge to a cat in a cat-room and by skin tests. Airborne Fel d 1 levels, symptom scores and peak expiratory flow (PEF) values were monitored.

RESULTS

Thirty-three (66%) out of 50 patients completed the treatment. Fel d 1 content of the maximum concentration was 0.51 microg per ml. During the build up phase, the accumulated dose was 1.7 mug of Fel d 1 and during the entire length of the study was 17.1. No adverse reports were reported. The active group showed a marked reduction (62%) in symptoms during the NCT (P < 0.001) with no changes in placebo group. Active group also showed a reduced PEF response to cat exposure (P < 0.05), and an improvement in skin test reactivity to a standardized cat extract (P < 0.05), without significant changes in placebo group. Mean Fel d 1 exposure during the NCT was 6.2 +/- 2.21 ng/m(3).

CONCLUSIONS

The results suggest that the cat SLIT used in this study was able to improve cat allergy based on natural exposure challenge.

Acaricidal activities of some essential oils and their monoterpenoidal constituents against house dust mite, Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

The acaricidal activities of fourteen essential oils and fourteen of their major monoterpenoids were tested against house dust mites Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 h under laboratory conditions. In general, it was noticed that the acaricidal effect based on LC(50) of either essential oils or monoterpenoids against the mite was time dependant. The LC(50) values were decreased by increasing of exposure time. Clove, matrecary, chenopodium, rosemary, eucalyptus and caraway oils were shown to have high activity. As for the monoterpenoids, cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of house dust mite, D. pteronyssinus.

Development of Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) at constant and simultaneously fluctuating temperature and humidity conditions

House dust mites are found in almost all dwellings in New Zealand and are a major risk factor in the development of asthma and perennial allergic rhinitis. We studied the longevity, life stage length, and fecundity of a New Zealand strain of European house dust mite, Dermatophagoides pteronyssinus (Trouessart), at constant (23 degrees C, 75% RH) and the fluctuating conditions typically found in dry (18-25 degrees C, 60-38% RH) and damp (18-23 degrees C, 70-55% RH) New Zealand dust mite microhabitats in carpets. All the adult mites placed in the "dry" conditions died within 18 d. Mites in the "da conditions had developmental times, oviposition, and death rates that were not significantly different from constant conditions. These mites are tolerant of fluctuating temperatures, but they are more susceptible to environments that strongly fluctuate in humidity.

Evaluation of home allergen sampling devices

BACKGROUND

Simple, inexpensive methods of sampling from allergen reservoirs are necessary for large-scale studies or low-cost householder-operated allergen measurement.

METHODS

We tested two commercial devices: the Indoor Biotechnologies Mitest Dust Collector and the Drager Bio-Check Allergen Control; two devices of our own design: the Electrostatic Cloth Sampler (ECS) and the Press Tape Sampler (PTS); and a Vacuum Sampler as used in many allergen studies (our Reference Method). Devices were used to collect dust mite allergen samples from 16 domestic carpets. Results were examined for correlations between the sampling methods.

RESULTS

With mite allergen concentration expressed as microg/g, the Mitest, the ECS and the PTS correlated with the Reference Method but not with each other. When mite allergen concentration was expressed as microg/m2 the Mitest and the ECS correlated with the Reference Method but the PTS did not. In the high allergen conditions of this study, the Drager Bio-Check did not relate to any methods.

CONCLUSIONS

The Mitest Dust Collector, the ECS and the PTS show performance consistent with the Reference Method. Many techniques can be used to collect dust mite allergen samples. More investigation is needed to prove any method as superior for estimating allergen exposure.

Compliance of asthmatic families with a primary prevention programme of asthma and effectiveness of measures to reduce inhalant allergens--a randomized trial

BACKGROUND

Compliance to and the effect of pre- and post-natal exposure reduction measures to prevent asthma in high-risk children from asthmatic families were studied.

METHOD

Families were randomized to a special care group (n=222) and a control group (n=221). Educational advice on measures to reduce their newborn's exposure to allergens and smoke was provided to the special care group during three visits (two pre-natal and one post-natal). The control group (n=221) received usual care.

RESULT

After the intervention, the special care group differed significantly (P<0.01) from the usual care group in: use of anti-mite encasings (parental: 88% vs. 14%; baby: 98% vs. 10%); keeping pets outside (51% vs. 19%); combined breast- and hypoallergenic formula feeding (55% vs. 22%); first solids postponement until after the sixth month (71% vs. 28%); maternal post-natal smoking (52% vs. 28%). Little or no compliance was found for other sanitary measures (cleaning habits, providing a smooth floor covering, ventilation/airing, pet removal), exclusive breastfeeding, pre-natal smoking and partner smoking. In spite of pre-existent low allergen levels in both groups, there was a significant reduction of mite, cat, and dog allergens on the mattresses and mite and cat allergens in the living room in the special care group and were significantly lower compared with the usual care group after 1 year.

CONCLUSION

High compliance was found for the use of anti-mite encasings; substantial compliance for using hypoallergenic formula, solid food postponement, keeping pets outside and reported post-natal maternal smoking. There was no compliance for sanitary measures and the reduction of maternal pre-natal passive smoking. Mite and pet allergens on mattresses were strongly reduced by anti-mite encasings.

House dust mite control measures for asthma

BACKGROUND

The major allergen in house dust comes from mites. Chemical, physical and combined methods of reducing mite allergen levels are intended to reduce asthma symptoms in people who are sensitive to house dust mites.

OBJECTIVES

To assess the effects of reducing exposure to house dust mite antigens in the homes of people with mite-sensitive asthma.

SEARCH STRATEGY

Cochrane Airways Group trials register, and PubMed and The Cochrane Library (last searches June 2004), reference lists.

SELECTION CRITERIA

Randomised trials of mite control measures vs placebo or no treatment in asthmatic people known to be sensitive to house dust mites.

DATA COLLECTION AND ANALYSIS

Two reviewers applied the trial inclusion criteria, assessed their quality and extracted the data independently. Study authors were contacted to clarify information.

MAIN RESULTS

Forty-nine trials (2733 patients) were included; the number of patients has more than doubled since the last version of this review. Thirty-one trials assessed physical methods, ten assessed chemical methods, and eight a combination of chemical and physical methods. Despite the fact that many trials were of poor quality and would be expected to exaggerate the reported effect, we did not find an effect of the interventions. For the most frequently reported outcome, peak flow in the morning (1339 patients), the standardised mean difference was -0.02 (95% confidence interval (CI) -0.13 to 0.08). There were no statistically significant differences either in number of patients improved (relative risk 1.01, 95% CI 0.80 to 1.27), asthma symptom scores (standardised mean difference -0.01, 95% CI -0.10 to 0.13), or in medication usage (standardised mean difference -0.05, 95% CI -0.18 to 0.09).

REVIEWERS' CONCLUSIONS

Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot be recommended. It is doubtful whether further studies, similar to the ones in our meta-analysis, are worthwhile. If other types of studies are considered, they should be methodologically rigorous and use other methods than those used so far, with careful monitoring of mite exposure and relevant clinical outcomes.

Predicting psychrometric conditions in biocontaminant microenvironments with a microclimate heat and moisture transfer model -- description and field comparison

A numerical model is described that is designed to model psychrometric conditions in biocontaminant microenvironments, such as in bedding and the base of carpets for dust-mites, and on the surface of linings for molds. The model is very general and can include room air, other room components, other zones including the outdoors, other rooms and any subfloor space. Mechanical plant can be modeled. Good agreement between modeled and field results are reported for the complex case of an occupied bed and for the microclimate in the base of a carpet, before and after its timber floor above a crawl space was retrofitted with insulation.

PRACTICAL IMPLICATIONS

Biocontaminants such as dust-mites and molds can pose serious health problems. Understanding microclimates in biocontaminant microhabitats, when coupled with biologic models, will make it possible to predict how the life cycles of these biocontaminants are affected as these conditions change. In turn, this will suggest which interventions that modify indoor climate and microclimate are likely to control these biocontaminants. Furthermore such interventions might include indoor humidity control, changing building insulation and ventilation levels, covering mattresses, use of electric blankets, use of carpet heating, etc. Such models will provide a fast way for screening for interventions that are likely to be effective in the control of biocontaminants.

Occupational therapy adaptation of the home environment in Sweden for people with asthma

The purpose of this study was to evaluate changes of lung function, respiratory symptoms and indoor air quality after reducing allergens and indoor pollutants in the home environment of people with asthma (n = 21). A quasi-experimental pre-/post-test design with one group of participants was implemented. The interventions included removal of wall-to-wall carpets (n = 14) or improvement of indoor air exchange (n = 7). Participants' lung function, symptoms, medication and type-1 allergy were recorded before and after the intervention. The indoor environment was monitored at house calls by an occupational therapist using conventional physical, biological and chemical methods. There was an improvement of lung function evidenced by an increased mean Forced Expiratory Volume (FEV(1) %) and a reduction of airway obstruction (reversibility, % of baseline value), which indicate an improved asthmatic condition. Lung function assessed by vital capacity, bronchial hyper-responsiveness, mean of Peak Expiratory Flow, symptom score and medicine consumption did not change significantly. There was a tendency that the amount of airborne dust (p=0.06) was reduced in the indoor environment. Relative humidity, carbon dioxide, formaldehyde and house dust mite levels had decreased after the intervention, but not significantly. Asthma symptoms related to the home environment are probably caused by several factors. When people with asthma suffer from increased symptoms in the home, house calls should be performed routinely. Dust samples from beds and carpets for analysis of allergens give information about exposure, and environmental assessments should be performed before interventions. Occupational therapists can make a valuable contribution in evaluating the home environment and suggesting ergonomic adaptations for individuals with asthma.

Disodium octaborate tetrahydrate (DOT) application and vacuum cleaning, a combined strategy to control house dust mites

BACKGROUND

The effectiveness of acaricides in homes is controversial.

OBJECTIVE

To determine whether disodium octaborate tetrahydrate (DOT) combined with vacuuming lowers dust mite numbers and their allergens in carpets and sofas.

METHODS

A 6-month study was carried out with 93 homes, which were randomized into three groups: (i). active, received DOT; (ii). placebo, received water; and (iii). control, received no application. Active and placebo homes were vacuumed weekly. Dust was collected from carpets and sofas at the start of the study and every 2 months thereafter and quantified for live, total mites, and mite allergen levels.

RESULTS

At 2 months, live mite numbers in active carpets were 3 +/- 1, in placebo carpets 129 +/- 48, and in control carpets 177 +/- 39 mites/g. The corresponding numbers in sofas were 3 +/- 2, 81 +/- 31, and 134 +/- 45 mites/g, respectively (P < 0.001 active vs placebo and vs. control). Live mites in carpets and sofas remained lower in the active group at 6 months (P < 0.001). Total mites in active carpets decreased from 555 +/- 69 at baseline to 223 +/- 32 mites/g at 6 months (P < 0.001) and mite allergen levels from 1.36 +/- 0.13 to 0.85 +/- 0.16 microg/g (P < 0.001). Total mites in active sofas remained unchanged, but mite allergen levels decreased from 1.48 +/- 0.25 at baseline to 0.7 +/- 0.15 microg/g at month 6 (P < 0.05).

CONCLUSION

DOT kills mites in carpets and sofas, and, combined with vacuuming, effectively reduces total mites in carpets and mite allergen levels in carpets and sofas.

Mattress encasings and mite allergen levels in the Prevention and Incidence of Asthma and Mite Allergy study

BACKGROUND

Reduction of allergen exposure from birth may reduce sensitization and subsequent allergic disease.

OBJECTIVE

To measure the influence of mite allergen-impermeable mattress encasings and cotton placebo encasings on the amount of dust and mite allergen in beds.

METHODS

A total of 810 children with allergic mothers took part in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study. Allergen-impermeable and placebo mattress encasings were applied to the childrens' and the parents' beds before birth. Dust samples were taken from the beds of children and their parents before birth and 3 and 12 months after birth. Extracts of dust samples were analysed for mite allergens (Der p 1 and Der f 1).

RESULTS

Active mattress encasings were significantly more effective in reducing dust and mite allergen levels than placebo encasings. Mite allergen levels were low in general and the treatment effect was modest. Twelve months after birth, mattresses with active mattress encasings had about half the amount of Der 1 (Der p 1 + Der f 1)/m2, compared to mattresses with placebo encasings, for the child's and the parental mattress.

CONCLUSION

This study shows that mite-impermeable mattress encasings have a significant but modest effect on dust and mite allergen levels of mattresses with low initial mite allergen levels, compared to placebo.

A rapid test for detection of mite allergens in homes

BACKGROUND

International guidelines recommend allergen avoidance for asthma management, but do not include making assessments of allergen exposure. Mite allergen exposure cannot be assumed, especially in geographical regions where climatic conditions vary.

OBJECTIVE

To develop a rapid test that would enable consumers to detect mite allergen in the home.

METHODS

A lateral flow test using gold labelled antibody for mite group 2 allergen was developed as part of a detection kit incorporating the MITEST dust sampling device. Dust samples were assayed by ELISA for group 1 and group 2 allergens and by using the rapid test. The tests were compared as indices of mite allergen exposure.

RESULTS

There was a good correlation between group 1 and group 2 levels by ELISA (n = 349, r = 0.60, P < 0.001). In a multi-centre study of 65 homes (263 dust samples) in five countries, there was a strong correlation between ELISA and the rapid test. Most samples with high scores in the test (43/48, 90%) contained > 1 microg/m2 group 2 allergen, whereas most low samples contained < 1 microg/m2 (50/64, 78%). Differences between mean group 2 levels of samples that scored low (0.28 microg/m2), medium (1.68 microg/m2) or high (3.18 microg/m2) on the test were highly significant (P 0.007 to < 0.001).

CONCLUSIONS

A simple rapid test has been developed that detects mite allergen in the home within 10 min. The mite screening test should educate consumers about allergen exposure and encourage compliance with allergen-avoidance procedures. This technology has applications for the detection of other common environmental allergens.

Allergens, Der p 1, Der f 1, Fel d 1 and Can f 1, in newly bought mattresses for infants

BACKGROUND

To avoid allergen exposure of newborn babies, the use of a new mattress for the baby bed may be recommended. However, it is not certain that new mattresses are always free of allergens.

OBJECTIVE

In the present study the allergen content of new infant mattresses was investigated.

METHODS

Dust samples were vacuumed from 90 new mattresses for infant beds bought in 50 different Dutch shops, and the concentrations of Der p 1, Der f 1, Fel d 1 and Can f 1 were determined by radioimmunoassays.

RESULTS

Most mattresses contained some allergen and often the allergen concentrations were surprisingly high. Only 15 of the 90 mattresses contained no detectable amounts of any of the four allergens. The highest concentration found for each allergen was 3.1, 46.5, 20.2 and 95.7 microg/g of dust, respectively. However, the total amount of allergen in a mattress was still rather low because the new mattresses contained only modest amounts of dust. Baby mattresses more often contained an increased allergen load than the larger, standard-sized, infant mattresses. This may be caused by differences in manufacturing procedure. Also, mattresses that were sold without a plastic encasement more often contained an increased allergen load.

CONCLUSIONS

It is advisable to buy a mattress that is wrapped in plastic, but it may still contain a substantial amount of allergen. Thorough vacuuming of a newly bought mattress before it is installed on a child's bed, is also advisable. After instalment, regular vacuuming of the mattress and washing of the bed linen as well as measures to eliminate allergen reservoirs in other parts of the house are important, because our observations indicate that mattresses easily pick up allergens from the environment.

Dust mite allergens: mitigation and control

In recent years, greater attention has been given to the role of indoor allergens as a cause of sensitization and allergic respiratory diseases. Although indoor allergen control measures to reduce symptoms in individuals allergic to mites have produced controversial results, environmental allergen avoidance is today one of the four primary goals of asthma management recommended in several guidelines of asthma treatment. Exposure to high indoor aeroallergen levels, especially to house dust mite allergens, is an important environmental risk factor for allergic sensitization and the subsequent development and exacerbation of asthma. Therefore, effective aeroallergen avoidance is of use to prevent and treat allergic diseases. Although endotoxin exposure may be protective in early life, it has been demonstrated that the inhalation of endotoxin may exacerbate asthma in house dust mite sensitized patients. Mite-allergic asthmatic patients should be aware of the dangerous combination of mite allergen exposure associated with high endotoxin levels in house dust. These two immunologically active substances have been associated with severe asthma and seasonal exacerbation of symptoms. Effective house dust mite allergen avoidance will never be achieved using a single control measure; various methods are required to affect the multiple factors that facilitate high indoor allergen levels. Education of the patients and their families is also an important component of environmental control strategies.

Wipe test for the detection of indoor allergens

BACKGROUND

The determination of house dust mite and cat allergens is a prerequisite for qualified assessment of exposure risk indoors. We describe the validation of integrated wipe tests comprising a porous sampling pin for the collection of settled house dust and an immunochemical test set-up for specific analysis of dust associated allergens.

METHODS

Wipe tests comprised an immunochromatographic test system and a porous sampling pin for collecting dust by manually wiping a surface. Two different wipe tests were developed with specificity to cat allergen (Fel d 1) and to dust mite allergen (Der p 2/f 2). One-hundred and fifty on-site determinations for each of the allergens in 50 different households completed the field study to validate the analytical system. Reference analysis was based on collection of dust with a vacuum cleaner and analysis of dust associated allergens by ELISA.

RESULTS

The wipe tests were found to produce semiquantitative results (class 0-3) on-site within 10 min of analysis time. For dust mite (cat) allergen the median of class 0-3 was 119 (263), 812 (844), 2708 (5670) and 8000 (56 800) ng/g dust, respectively. With respect to cut-off levels for dust mite (cat) allergens the clinical sensitivity was 62% (79%) and the clinical specificity was 94% (92%).

CONCLUSIONS

The wipe tests proved to be a reliable tool for indoor allergen exposure screening, suitable for use even by untrained persons. This may have an impact on compliance with allergen avoidance measures.

Effectiveness of and compliance to intervention measures in reducing house dust and cat allergen levels

BACKGROUND

Allergic sensitization is a major risk factor in asthma.

OBJECTIVE

To evaluate the effectiveness of and compliance to intervention measures in reducing levels of house-dust mite and cat allergen in the context of a randomized, controlled study in the primary prevention of asthma.

METHODS

A total of 545 high-risk families were recruited prenatally and randomly assigned into the intervention group (n = 278) and the control group (n = 267). Intervention measures were instituted before birth of the infants and maintained for 12 months afterward in the intervention group and the control group received the usual care from their family physician. Dust samples were collected at six sites in the homes before birth and at specific intervals up to 24 months after birth for analysis of allergens. At 24 months, there were 244 families in the intervention group and 228 in the control group available for followup examination.

RESULTS

House-dust mite avoidance measures, consisting of encasement of mattresses, pillows, and duvets, and hot-water washing of bedding were effective in reducing mite allergen in parents' mattresses to one-third from baseline, significantly lower than the control group, even at 24 months. The use of an acaricide did not reduce mite allergen levels in carpets and upholstered furniture. Seventeen intervention families gave up their cats but six families acquired a new one over a period of 24 months, similar to control families. Cat allergen levels decreased in all sites in the homes of those who removed the cat, similar in both groups.

CONCLUSIONS

House-dust mite avoidance measures were effective in reducing house-dust mite allergen in mattresses, but not on floors. Reduction in cat allergen levels were evident for those families who got rid of their cats, but the advice to remove pets was not adhered to by most families.

Evaluation of an asthma management program for Chinese children with mild-to-moderate asthma in Hong Kong

There is inconclusive evidence on the efficacy of outpatient clinic-based asthma management programs (AMP) in children. We hypothesized that an AMP based on key symptoms could improve outcome measures of asthma in Chinese children in Hong Kong. This study involved an outpatient clinic-based prospective cohort of Chinese children with asthma. Each patient received one 2-hr session of AMP which was conducted by a pediatric nurse specialist. Asthma outcomes were measured at baseline and at 6 and 12 months after completion of AMP. Demographic data, family history of allergic diseases, and changes in inhaled steroid therapy were also recorded. A total of 106 asthmatic children were enrolled, and they showed a significant decrease in nocturnal cough, wheezing attacks, and subjective assessment of severity at 6 and 12 months following participation in AMP, compared with their baseline status. Acute asthmatic attacks, unscheduled outpatient attendance, emergency room visits, school absenteeism, and number and duration of hospitalizations were also reduced during the follow-up period. Significantly more (21%) children were reported to use inhaled beclomethasone at the end of the study. Nocturnal cough, wheeze, and symptoms due to rhinitis improved significantly after AMP. In conclusion, our cohort of Chinese children with mild-to-moderate asthma used significantly more inhaled corticosteroids and practiced more measures to control house dust mites at the end of the 1-year treatment period. The main reason for better asthma control appeared to be related to the increased use of inhaled steroids, although some additional decrease in nocturnal cough, wheeze, and allergic rhinitis was found after adjusting for the use of inhaled corticosteroids.

A side-by-side comparison of sampling methods for settled, indoor allergens

Exposure to indoor allergens is associated with asthma, but there is no standardized sampling method for measuring allergens. We compared the association of measured allergen exposure and serum-specific IgE levels and the precision of three sampling methods (Cyclone, Mighty Mite, and Readivac II) to identify a standardized sampling method for indoor allergens. A random sample of 72 children, 5 to 17 years old, with doctor-diagnosed asthma who lived in the same residence >or=2 years were enrolled. Composite, side by side floor samples were obtained with all three methods. Dust allergen concentrations and serum-specific IgE levels were measured for Der f I, Fel d I, and Bla g I. Mean allergen concentration did not differ significantly by sampling method. Cat allergen was significantly correlated with serum-specific IgE for Cyclone (P=0.003) and Mighty Mite (P=0.008), but only marginally for Readivac II (P=0.07). Dust mite allergen was significantly correlated with serum-specific IgE for Readivac II (P=0.02) and Cyclone (P=0.038), but not for Mighty Mite (P=0.12). Cockroach allergen was not correlated with serum-specific IgE for any sampling method. In multiple linear regression, cat allergen was associated with serum-specific IgE for Cyclone (P=0.007) and Mighty Mite (P=0.02), but not for Readivac II (P=0.06). In contrast, dust mite allergen was marginally associated with serum-specific IgE for Readivac II (P=0.07), but not for Mighty Mite (P=0.64) or Cyclone (P=0.27). The Cyclone and Mighty Mite were more precise than Readivac II for cat allergen, but there was no difference for dust mite allergen (P>0.05). No single method is superior for measurement of indoor allergens. In general, cat allergen collected with the Cyclone was a better predictor of serum-specific IgE levels to Fel d I, whereas dust mite allergen collected with the Readivac II was a better predictor of serum-specific IgE levels to Der f I.

Effect of gas cooking on lung function in adolescents: modifying role of sex and immunoglobulin E

BACKGROUND

A study was undertaken to investigate the effect of gas cooking on the lung function of adolescents while considering serum IgE level as a possible effect modifier.

METHOD

The cross sectional study was performed in 702 subjects aged 11–13 years from primary and secondary schools in Civitavecchia and Viterbo ( Latium region in Central Italy), categorised according to how often they were in the kitchen while the mother cooked (never, sometimes, often). Data were collected by questionnaire and lung function was measured by spirometric tests. Bronchial hyperresponsiveness was evaluated by the methacholine test, atopic status by a skin prick test, and a blood sample was collected to determine serum IgE levels. The results were analysed separately for boys and girls. Multiple regression analysis was performed, taking functional parameters (FEV1, FEV1/FVC, FEF25–75, FEF50, FEF75) as the dependent variables and age, height, parental smoking, and father's education as independent variables.

RESULTS

There was no association between time spent in the kitchen and lung function level in boys, but a reduction in lung function was detected in girls which was statistically significant for FEF75 (sometimes –10.3%, often –11.1%). After stratifying boys and girls into four groups on the basis of the IgE serum level (below and above the median value of IgE), the reduction in lung function was significant in girls with a high IgE value whereas no significant deleterious effects were evident in girls with a low IgE value or in boys with either a low or high IgE. The results remained substantially unchanged after excluding girls with a response to methacholine below the concentration of 4 mg/ml, asthmatic patients, and those with positive skin prick tests.

CONCLUSION

Gas cooking has a harmful effect on the lung function of girls with a high serum level of IgE. We do not know whether serum IgE, a marker of allergic susceptibility, is a simple indicator that an inflammatory process is in progress or whether it is involved in the pathogenesis of injury leading to bronchial obstruction.

Effect of gas cooking on lung function in adolescents: modifying role of sex and immunoglobulin E

BACKGROUND

A study was undertaken to investigate the effect of gas cooking on the lung function of adolescents while considering serum IgE level as a possible effect modifier.

METHOD

The cross sectional study was performed in 702 subjects aged 11-13 years from primary and secondary schools in Civitavecchia and Viterbo ( Latium region in Central Italy), categorised according to how often they were in the kitchen while the mother cooked (never, sometimes, often). Data were collected by questionnaire and lung function was measured by spirometric tests. Bronchial hyperresponsiveness was evaluated by the methacholine test, atopic status by a skin prick test, and a blood sample was collected to determine serum IgE levels. The results were analysed separately for boys and girls. Multiple regression analysis was performed, taking functional parameters (FEV(1), FEV(1)/FVC, FEF(25-75), FEF(50), FEF(75)) as the dependent variables and age, height, parental smoking, and father's education as independent variables.

RESULTS

There was no association between time spent in the kitchen and lung function level in boys, but a reduction in lung function was detected in girls which was statistically significant for FEF(75) (sometimes -10.3%, often -11.1%). After stratifying boys and girls into four groups on the basis of the IgE serum level (below and above the median value of IgE), the reduction in lung function was significant in girls with a high IgE value whereas no significant deleterious effects were evident in girls with a low IgE value or in boys with either a low or high IgE. The results remained substantially unchanged after excluding girls with a response to methacholine below the concentration of 4 mg/ml, asthmatic patients, and those with positive skin prick tests.

CONCLUSION

Gas cooking has a harmful effect on the lung function of girls with a high serum level of IgE. We do not know whether serum IgE, a marker of allergic susceptibility, is a simple indicator that an inflammatory process is in progress or whether it is involved in the pathogenesis of injury leading to bronchial obstruction.

Quantification of group 5 grass pollen allergens in house dust

BACKGROUND

It is widely known and accepted that grass pollen is a major outdoor cause of hay fever. However, it is of virtual importance for grass pollen allergic patients with symptoms all the year round to know the concentration of grass pollen allergens in their homes.

OBJECTIVE

The main objective of this study was to quantify the amount of grass pollen allergen in mass units (microg Phl p 5) in dust settled indoors and to detect the distribution of allergenic activity in different sampling locations of homes. Furthermore, we studied the seasonal fluctuation of allergen content in dust samples.

METHODS

We adapted the two site binding assay for detection of group 5 grass pollen allergens in samples from randomly selected homes in Hamburg (n = 371), Erfurt (n = 396), Hettstedt (n = 353), Zerbst (n = 289) and Bitterfeld (n = 226), Germany. Dust samples were collected from floor of living room (LR), bedroom (BR) or children's room (CR) and mattress (MA) during period of June 1995 to August 1998. The amount of the major grass group 5 allergens was detected in microg/g dust.

RESULTS

Phl p 5 was detected in 67% of the samples analysed (n = 4760). The range was between undetectable (< 0.03 microg/g dust) and 81 microg/g dust. Phl p 5 levels were significantly higher in the dust from LR (geometric mean 0.117 microg/g dust) or BR/CR floors (geometric mean 0.098 microg/g dust) than in mattresses (geometric mean 0.043 microg/g dust). We observed seasonal fluctuation of indoor Phl p 5 levels with peak in June but also annual differences. Thus Phl p 5 content indoors reflects also the different quantities of pollen counts of annual courses. During pollination period we found two times higher Phl p 5 levels (0.172 microg/g dust, P < 0.001) than outside of grass pollination season (0.095 microg/g dust). The indoor Phl p 5 levels outside of season seem to be independent of pollination before. We suppose that settled pollen grains or allergenic material from outdoor particles carried indoors via footwear and clothes accumulates in house dust.

CONCLUSION

Although we not known how the allergens in settled dust are equilibrated with those in the air, the considerable high level of Phl p 5 in indoor dust even during periods when no grass pollen is present in the atmosphere may be an important cause of pollen-allergy symptoms outside of season.

The role of intervention in established allergy: avoidance of indoor allergens in the treatment of chronic allergic disease

Avoidance of exposure to indoor allergens is an important element in the treatment of allergic disease. The results of several studies provide strong evidence in support of a role for allergen avoidance; however, strategies that optimize allergen reduction in houses have not been determined. Complex issues regarding the efficacy of physical and chemical measures that target house dust mite, pet, and cockroach allergens in the home are discussed. The greatest challenge is to educate allergic patients so that they can play an important role in controlling their own disease.

(1-->3)-beta-D-glucan and endotoxin in house dust and peak flow variability in children

House dust-associated bacterial endotoxins have been shown to be associated with asthma severity, and a similar role has been suggested for fungal (1-->3)-beta-D-glucans. In this study the relation between these agents and peak expiratory flow (PEF) variability was investigated in 148 children 7 to 11 yr of age of whom 50% had self- or parent-reported chronic respiratory symptoms. All children self-monitored twice daily their PEF for a period of 16 wk. Dust samples were collected from mattresses and from living room and bedroom floors, and endotoxin and (1-->3)-beta-D-glucan were measured in dust extracts. The relations with mean daily PEF variability (Ampl%mean) were investigated by linear regression analysis, adjusting for dust mite allergen levels, presence of pets, and type of floor cover. In unadjusted analyses the levels of both endotoxin and (1--> 3)-beta-D-glucan per square meter of living room floor were significantly associated with PEF-variability (but not when expressed per gram of sampled dust), particularly in atopic children with asthma symptoms. Adjusted analyses showed the same association for (1--> 3)-beta-D-glucan but not for endotoxin. Although no associations were found with microbial agent levels in bedroom floor or mattress dust, high levels of (1-->3)-beta-D-glucan in living room floor dust apparently increase PEF variability in asthmatic children.