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Isotype specific immunoglobulin responses to the house dust mite Dermatophagoides pteronyssinus and the purified allergen Der p 1 in asthmatic and control subjects from the Eastern Highlands of Papua New Guinea.

The IgG, IgE and IgA antibody responses to the whole mite extract and a purified major mite allergen Der p 1, in sera from asthmatic and age- and sex-matched control subjects from the South Fore region of the Eastern Highlands of Papua New Guinea, have been studied. Radio-allergosorbent studies showed that the majority of the asthmatics, in contrast to control subjects, produced IgE to whole mite extract, and that Der p 1 was a major allergen in this population with 88% of mite allergic asthmatics responding. Enzyme-linked immunosorbent assay studies on these sera showed that the geometric mean levels of whole mite, but not Der p 1, specific IgG and IgA were significantly higher in the asthmatic group than in the control group. Significant correlations between whole mite specific IgG, IgE and IgA responses were obtained. These data indicate that Papua New Guinean asthmatics are similar to Caucasian asthmatic population with regard to serological responses to mite allergens, despite differences in disease presentation, particularly the late age of onset and severity of symptoms.

Adult↗

Increased immune reactivity to house dust mites in adults with chronic rhinosinusitis.

Sixty-three adults with symptomatic chronic rhinosinusitis had computerized tomographic (CT) scans of the paranasal sinuses, which were used to quantify disease severity. These patients were divided into three closely age- and sex-matched groups: a CT scan-negative group (chronic rhinitis only), a mild sinusitis group and a severe sinusitis group. Serum dust mite-specific IgG levels were found to be significantly elevated in the sinusitis patients compared with a matched group of asymptomatic normal individuals. Levels were highest in the more severe sinusitis group, in which the mean titre was 559 U/ml and the incidence of titres greater than 400 U/ml was 48%, as compared with a mean titre of 139 U/ml and only a 10% incidence of titres greater than 400 U/ml in the normal subjects (P < 0.005 and < 0.01). In contrast, although the frequency of immediate hypersensitivity to dust mite, as assessed by intradermal skin tests, tended to be higher in patients with sinusitis, it was not significantly different from normal individuals. The association between mite IgG and disease was most striking in the patient sub-group with negative mite skin tests. In this group, mite IgG levels were significantly higher than normal, even in those patients with only chronic rhinitis. These findings demonstrate that increased serum levels of IgG against dust mites are strongly associated with chronic rhinosinusitis, especially in the sub-group of patients who are not allergic to mites.

Adolescent↗

Crossreactivity between Dermatophagoides siboney and other house dust mite allergens in sensitized asthmatic patients.

BACKGROUND: The role of Pyroglyphid mites in IgE-mediated sensitization has been well established. Although mites belonging to the genus Dermatophagoides dominate in the acarofauna of domestic dust, non-pyroglyphid mites might also be of clinical importance. In Cuba, Dermatophagoides siboney is found in dust coexisting with D. pteronyssinus and Blomia tropicalis. Dermatophagoides farinae is not found. Storage mites, such as Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae, might also be present. OBJECTIVES: The aim of this study was to investigate the allergenic relationships among the mites present in the environment of allergic patients in Cuba. METHODS: The crossreactivity between an extract of D. siboney and the above mentioned six mites was studied by specific IgE inhibition, using sera of mite-sensitive patients after incubation with serial dilutions of D. siboney. RESULTS: The inhibitory effect of D. siboney extract was more pronounced against D. farinae, 91%, than against D. pteronyssinus, 62%. Specific IgE to B. tropicalis, A. siro, L. destructor and T. putrescentiae were inhibited to a much lesser extent, i.e. between 47 and 58%. The correlation between IgE to D. siboney and IgE to D. pteronyssinus and D. farinae was of 0.92 and 0.90, respectively. A weaker correlation was found between D. siboney and L. destructor (0.7), A. siro (0.67), B. tropicalis (0.54) and T. putrescentiae (0.51). CONCLUSION: Thus, D. siboney seems to be most closely related to D. farinae.

Adolescent↗

House dust mite allergen levels in two cities in Canada: effects of season, humidity, city and home characteristics.

The homes of 120 patients with asthma, 57 in Vancouver and 63 in Winnipeg, were studied. The characteristics of the homes were assessed by a questionnaire. Dust samples were collected and the indoor relative humidity was measured four times during the year covering all four seasons in both cities. Mite allergen levels were determined using monoclonal antibodies against Der p I and Der f I by the ELISA method. The mean levels of both mite allergens in mattress and floor samples in the homes in Vancouver and in Winnipeg were relatively low for all seasons. Mite allergen levels were found to be associated with city, season and individual home differences. They were significantly higher in Vancouver than in Winnipeg. Der p I and Der f I in mattress samples in both cities and Der f I in floor samples in Vancouver, varied by season. The indoor relative humidity level in the homes in Vancouver were also significantly higher than those in Winnipeg. There was, however, no significant association between the levels of indoor relative humidity and the levels of mite allergens after adjusting for variations in city, season and individual home. Although individual home differences were highly associated with mite allergen levels, only a few home characteristics were found to be related to mite allergen levels such as the type and the age of the home, the type of heating, the use of feather pillows and the number of occupants in the homes. Whether low levels of mite allergens are partially responsible for the relatively low prevalence of childhood asthma in Canada remains to be investigated.

Allergens↗

Storage mite allergy among bakers.

Allergy to storage mites has been shown among farmers and grain elevator workers. This study aimed to examine whether bakers also are sensitized to storage mites. Twenty-three bakers or other employees in bakeries suffering from nasal or pulmonary symptoms were compared with 17 control persons with no relation to bakery work or agriculture. All participants underwent skin prick test with a standard panel of allergens, four types of flour and the storage mites Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae, RAST to storage mites and flour, and measurement of total IgE. We found no difference between the baker group and the control group in prevalence and strength of positive skin prick test or RAST to any of the three storage mite species. In the baker group positive RAST to flour was related to positive RAST to A. siro and L. destructor, but not T. putrescentiae. Almost all bakers sensitized to flour were also sensitized to storage mites (6 of 7). We suggest that if a baker become sensitized to flour he will be more prone to develop specific IgE towards storage mites too.

Animals↗

Epidemiology of house-dust mites.

Available epidemiologic data on the occurrence of house-dust mites in dwellings demonstrates a clear association between increased indoor air humidity and the increased occurrence of house-dust mites in house dust. Furthermore, in temperate climates, there is a threshold level of indoor air humidity of 7 g/kg (45% relative humidity at usual indoor air temperatures). Indoor air humidities below this level for extended periods will eradicate house-dust mites from dwellings. A reduction in inhabitant exposure to house-dust mites is implemented by reduction of indoor air humidity by controlled mechanical ventilation. Individual ventilation levels are estimated from the actual size of house, number of inhabitants, and average outdoor air humidity in winter. In contrast, more humid areas of the world with average outdoor humidities above 6-7 g/kg in winter will support uniformly large populations of house-dust mites, and reductions in indoor air humidity will have a comparatively minor effect on the occurrence of house-dust mites. Present-day building of energy-efficient houses with increased sealing of the building envelope, paralleled by a similar renovation of older houses, has increased indoor air humidity and is probably the cause of the almost fourfold increase in the occurrence of house-dust mites in Danish dwellings.

Allergens↗

Peak expiration flow variations may reflect house-dust-mite exposure and patient reactivity.

Peak expiration flow records from patients allergic to house-dust mites (Dermatophagoides spp.) may show a characteristic variation from week to week due to the general life cycle of these mites in dwellings. This was demonstrated from the combined records of 10 patients recorded in their own homes, covering a period of 30 consecutive weeks and comprising 973 peak flows. The levels of house-dust mites were predicted from published data for floor-dust samples from Danish dwellings. Peak flow increased or decreased in accordance with weekly changes in the concentration of mites, rather than as an immediate reaction to the current concentration of live, active mites. A dose-response relation was demonstrated. This suggests that the patients' peak flow variations might be linked to molting in mites. As such, peak flow measurements have a potential as a tool for the specific diagnosis of, monitoring of, and research in asthma caused by domestic mites.

Adolescent↗

High-efficiency vacuum cleaners increase personal mite allergen exposure, but only slightly.

BACKGROUND: High-efficiency particulate-arrest-filter vacuum cleaners are recommended to allergy sufferers although their use increases personal cat allergen exposure. We aimed to measure personal mite allergen exposure during vacuum cleaning by nasal air sampling and to compare exposures while vacuuming and emptying the vacuum cleaner bag. METHODS: Five brand new high-efficiency vacuum cleaners were selected. An old, previously used vacuum cleaner with its original microfilter in situ was used as a control. Nasal air samples were taken prior to and during vacuum cleaning in 10 homes. Samples were processed by HALOgen assay. Personal mite and cat allergen exposure was measured as the dust compartments were emptied. RESULTS: There was an increase in personal mite allergen exposure with vacuum cleaning, which approached significance (P = 0.058). There was no difference between the high-efficiency vacuum cleaners and the control vacuum cleaner (P = 0.141). When the dust compartments were emptied, personal mite and cat allergen exposure increased (P < 0.02). CONCLUSIONS. The increase in personal mite allergen exposure while vacuum cleaning in an area with mild to moderate mite allergen exposure is small. High-efficiency vacuum cleaners confer no benefit and cannot currently be recommended to allergy sufferers as a means of reducing personal mite allergen exposure.

Air Pollution, Indoor↗

The occurrence of mite-containing wheat flour.

Anaphylaxis after eating mite-infested wheat flour has been recently reported. This paper is to describe two cases and examine the occurrence of mite contamination in wheat flour in Japan. Packages of wheat flour from retail outlets and homes were examined microscopically for the presence of mites. Three of 176 packages from retail outlets and seven of 127 from homes were infested with mites, and it seems likely that the mite contamination takes place in most cases at homes after the packages have been opened. No mites were found in packages stored in a refrigerator, therefore, mite-sensitive patients must be advised to store wheat flour products in a refrigerator.

Adolescent↗

Parasites and pathogens of mites.

Mites are an ancient group of arachnids that have had some 400 million years to adapt to a variety of conditions on Earth. Microorganisms have had the same amount of time to form symbiotic relationships with mites, with results ranging from phoresy to parasitism. This review covers the still fragmentary information on the groups of parasites and pathogens that are associated with mites. The known mite-associated bacteria, rickettsiae, fungi, Protozoa, viruses, and nematodes represent the tip of the iceberg, and few details of their host-parasite relationships have been recorded. Mites offer an opportunity to investigate new pathogens and new types of associations. Pathogens can be a boon when they affect mites that are detrimental to crops, livestock, or ourselves, and the diseases they cause probably play an important role in controlling mites, at least under certain conditions. However, pathogens can also cause crop failure and economic loss when they occur in biological control agents of pests.

Animals↗

Feather mites (Acari: Astigmata): ecology, behavior, and evolution.

Birds host many lineages of symbiotic mites, but the greatest diversity is shown by the three superfamilies of astigmatan feather mites: Analgoidea, Pterolichoidea, and Freyanoidea. Members of this diphyletic grouping have colonized all parts of the avian integument from their ancestral nidicolous habitat. Whereas some clearly feed on feather pith or skin, acting as parasites, other feather mites are paraphages and consume feather oils without causing structural damage. Sexual dimorphism in feather mites is often extreme, and little is known of the function of many elaborate male structures. Abundance and location of vane-dwelling mites is affected by season, temperature, light, humidity, and host body condition. Because transmission between hosts usually depends on host body contact, it is unsurprising that feather mite phylogeny often parallels host phylogeny; however, recent cladistic analyses have also found evidence of host-jumping and "missing the boat" in several mite lineages.

Adaptation, Physiological↗

Atopic dermatitis-like skin lesions induced by topical application of mite antigens in NC/Nga mice.

BACKGROUND: Atopic dermatitis (AD) is a chronic relapsing inflammation usually observed in patients with an individual or a familial history of atopic diseases, precipitated by environmental factors including mite antigens (Ag). However, the exact etiology of AD is unclear. To further explore the pathogenesis and treatment of AD, a suitable animal model is necessary. In this study, we developed a new animal model of AD induced by mite Ag in NC/Nga mice. METHODS: We injected the extracts of mite Ag intradermally at the ventral side of the ear of SPF NC/Nga mice on days 0, 2, 4, 7, 9, 11, 14 and 16, and measured the clinical symptoms and the ear thickness. On day 18, we collected blood and submandibular lymph nodes (LN) of the immunized ear to perform a histochemical analysis, and to measure the plasma immunoglobulins and cytokines. RESULTS: The NC/Nga mice immunized with mite Ag suffered from AD-like skin lesions including erythema followed by edema, excoriation and scaling. The histological and immunohistochemical examinations of the affected skin showed epidermal hyperplasia with hyperkeratosis, severe infiltration of CD4+ T lymphocytes, eosinophils and macrophages, and degranulation of mast cells. The total plasma IgE level was markedly elevated in mite Ag-treated mice. LN cells of mice immunized with mite Ag synthesized IgE in an Ag-dependent manner and secreted interleukin-4 (IL-4) and IL-5 but not interferon-gamma. CONCLUSIONS: NC/Nga mice treated with mite Ag manifest clinical and immunological aspects similar to patients with AD, suggesting that this model is suitable for exploring the pathogenesis of human AD.

Allergens↗

Immunoglobulin E antibody production against house dust mite, Dermatophagoides farinae, in mice.

Immunoglobulin E (IgE) antibody production against Dermatophagoides farinae extract (mite antigen) was studied in female BALB/c mice. When mice were immunized with mite antigen and aluminium hydroxide gel (alum) intraperitoneally at intervals of 30 d, good primary, secondary and tertiary IgE antibody responses were observed. In the absence of adjuvant, a subcutaneous injection of mite antigen failed to induce the primary IgE antibody response. However, good IgE antibody responses were observed after the secondary immunization given 30 d after the primary immunization. Furthermore, 5 weekly injections of mite antigen alone also induced the IgE antibody production. Intranasal administrations of mite antigen alone also induced the IgE antibody production in mice. Two exposures to mite antigen, intranasally, were sufficient for eliciting low IgE antibody production. The response was significantly potentiated by the administration of islet-activating protein obtained from culture fluids of Bordetella pertussis. These results indicate that the intranasal administration of mite antigen is very effective for eliciting the IgE antibody production.

Adjuvants, Immunologic↗

Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes.

House dust mite allergen exposure is a postulated risk factor for allergic sensitization, asthma development, and asthma morbidity; however, practical and effective methods to mitigate these allergens from low-income, urban home environments remain elusive. The purpose of this study was to assess the feasibility and effectiveness of physical interventions to mitigate house dust mite allergens in this setting. Homes with high levels of house dust mite allergen (Der f 1 + Der p 1 > or = 10 microg/g dust by enzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or upholstered furniture were enrolled in the study. Carpets and upholstered furniture were subjected to a single treatment of either dry steam cleaning plus vacuuming (carpet only) or intensive vacuuming alone. Bed interventions consisted of complete encasement of the mattress, box spring, and pillows plus either weekly professional or in-home laundering of nonencased bedding. Dust samples were collected at baseline and again at 3 days (carpet and upholstery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment mean allergen concentrations and loads to posttreatment values and performed between-group analyses after adjusting for differences in the pretreatment means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted in a significant reduction in carpet house dust mite allergen concentration and load (p < 0.05). Levels approached pretreatment values by 4 weeks posttreatment in the intensive vacuuming group, whereas steam cleaning plus vacuuming effected a decrease that persisted for up to 8 weeks. Significant decreases in bed house dust mite allergen concentration and load were obtained in response to encasement and either professional or in-home laundering (p < 0.001). Between-group analysis revealed significantly less postintervention house dust mite allergen load in professionally laundered compared to home-laundered beds (p < 0.05). Intensive vacuuming and dry steam cleaning both caused a significant reduction in allergen concentration and load in upholstered furniture samples (p < 0.005). Based on these data, we conclude that physical interventions offer practical, effective means of reducing house dust mite allergen levels in low-income, urban home environments.

Allergens↗

Field trials using the fungal pathogen, Metarhizium anisopliae (Deuteromycetes: Hyphomycetes) to control the ectoparasitic mite, Varroa destructor (Acari: Varroidae) in honey bee, Apis mellifera (Hymenoptera: Apidae) colonies.

The potential for Metarhizium anisopliae (Metschinkoff) to control the parasitic mite, Varroa destructor (Anderson and Trueman) in honey bee colonies was evaluated in field trials against the miticide, tau-fluvalinate (Apistan). Peak mortality of V. destructor occurred 3-4 d after the conidia were applied; however, the mites were still infected 42 d posttreatments. Two application methods were tested: dusts and strips coated with the fungal conidia, and both methods resulted in successful control of mite populations. The fungal treatments were as effective as the Apistan, at the end of the 42-d period of the experiment. The data suggested that optimum mite control could be achieved when no brood is being produced, or when brood production is low, such as in the early spring or late fall. M. anisopliae was harmless to the honey bees (adult bees, or brood) and colony development was not affected. Mite mortality was highly correlated with mycosis in dead mites collected from sticky traps, indicating that the fungus was infecting and killing the mites. Because workers and drones drift between hives, the adult bees were able to spread the fungus between honey bee colonies in the apiary, a situation that could be beneficial to beekeepers.

Animals↗

Spatiotemporal distribution of insects and mites in horizontally stored wheat.

Samples were taken from a flat storage facility located in central Greece, filled with approximately 45 tons of hard wheat, to assess the spatiotemporal distribution of stored-product insects and mites. The wheat was stored in a 1.5-m-deep bulk from June 2001 until March 2002. The samples were taken with a partitioned grain trier during the entire storage period, at 10-d intervals. The trier samples were examined separately for the upper, medial, and lower 0.5 m of the bulk. The spatial distribution of the insect and mite species found was examined by contour analysis based on the numbers of individuals in the trier samples. Nine insect and 20 mite taxa were found during the sampling period. The most abundant insect species were Tribolium castaneum (Herbst), Cryptolestes ferrugineus (Stephens), and Rhyzopertha dominica (F.); the most abundant mite species were Lepidoglyphus destructor (Schrank), Acarus siro L., and the predator Cheyletus malaccensis Oudemans. The highest population densities for the majority of the insect and mite species were recorded during autumn. The majority of the individuals of the most abundant insect and mite species were found in the upper 0.5 m of the bulk, with the exception of C. malaccensis, which was equally distributed in the upper and medial 0.5 m of the bulk. The spatiotemporal distribution during the entire experimental period was notably varied according to the insect and mite species.

Animals↗

Does plant species co-occurrence influence soil mite diversity?

Few studies have considered whether plant taxa can be used as predictors of belowground faunal diversity in natural ecosystems. We examined soil mite (Acari) diversity beneath six grass species at the Konza Prairie Biological Station, Kansas, USA. We tested the hypotheses that soil mite species richness, abundance, and taxonomic diversity are greater (1) beneath grasses in dicultures (different species) compared to monocultures (same species), (2) beneath grasses of higher resource quality (lower C:N) compared to lower resource quality, and (3) beneath heterogeneous mixes of grasses (C3 and C4 grasses growing together) compared to homogeneous mixes (C3 or C4 grasses) using natural occurrences of plant species as treatments. This study is the first to examine the interaction between above- and belowground diversity in a natural setting with species-level resolution of a hyper-diverse taxon. Our results indicate that grasses in diculture supported a more species and phylogenetically rich soil mite fauna than was observed for monocultures and that this relationship was significant at depth but not in the upper soil horizon. We noted that mite species richness was not linearly related to grass species richness, which suggests that simple extrapolations of soil faunal diversity based on plant species inventories may underestimate the richness of associated soil mite communities. The distribution of mite size classes in dicultures was considerably different than those for monocultures. There was no difference in soil mite richness between grass combinations of differing resource quality, or resource heterogeneity.

Animals↗

Reactivity to intradermal injection of extracts of Dermatophagoides farinae, Dermatophagoides pteronyssinus, house dust mite mix, and house dust in dogs suspected to have atopic dermatitis: 115 cases (1996-1998).

OBJECTIVE: To compare reactivities to intradermal injection of extracts of Dermatophagoides farinae, Dermatophagoides pteronyssinus, house dust mite mix, and house dust in dogs suspected to have atopic dermatitis. DESIGN: Retrospective study. ANIMALS: 115 dogs. PROCEDURES: Records of all dogs suspected to have atopic dermatitis that underwent intradermal testing between October 1996 and July 1998 were reviewed. Reactivities to intradermal injection of crude mixed house dust mite (1:25,000 wt/vol) and crude house dust (25 PNU/ml) extracts were compared with reactivities to intradermal injection of individual extracts of D farinae and D pteronyssinus (1:50,000 wt/vol). RESULTS: Ninety dogs were confirmed to have atopic dermatitis including 61 of the 69 dogs with positive reactions to either or both of the individual house dust mite extracts. Intradermal testing with the mixed house dust mite extract had sensitivity of 75%, specificity of 96%, and accuracy of 83%. Intradermal testing with the house dust extract had sensitivity of 30%, specificity of 93%, and accuracy of 56%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of crude mixed house dust mite and crude house dust extracts for intradermal testing in dogs is not as accurate a method of determining house dust mite hypersensitivity as is the use of individual D farinae and D pteronyssinus extracts mainly because of the high percentage of false-negative results. Extracts of individual house dust mites are recommended for intradermal testing of dogs suspected to have atopic dermatitis.

Allergens↗