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PubMed2002

Household characteristics and mite allergen levels in Manchester,UK.

BACKGROUND: Mite allergen levels vary enormously between different homes in the same geographical area. No large scale studies of mite levels in Manchester homes has been conducted to identify factors associated with higher levels. OBJECTIVES: To quantify exposure to mite allergens and to identify characteristics associated with higher Der p 1 levels in a large sample of homes in Manchester, UK. METHODS: Der p 1 was measured in dust from the living room floor, sofa, bedroom floor and mattress in 564 homes. Data on household characteristics were collected by administering a questionnaire. Univariate and multivariate analyses were performed to identify household characteristics associated with higher mite allergen levels. RESULTS: Der p 1 levels were highest in the mattress (GM 1.19 microg/g, 95% CI 0.98-1.45, P < 0.001). Two-thirds of homes contained Der p 1 levels > 2 microg/g in at least one dust reservoir, and 40.3% contained Der p 1 greater than 10 microg/g. There was a large range in Der p 1 levels between homes (> 10(3)-fold). Damp and condensation were common findings in homes. In the multivariate analyses, factors associated with higher Der p 1 levels in more than one dust reservoir were older homes, older living room carpets, damp, condensation and mixed glazing. Older mattresses were associated with higher mite allergen levels in the mattress where the age of the mattress was recorded. Twenty-four homes contained no detectable mite allergen, six of which reported damp. CONCLUSIONS: Mite allergen levels are high enough in two of every three homes to be associated with an increase in the risk of sensitization to mite. Factors such as older homes, carpets and mattresses, damp and condensation are associated with higher mite allergen. However, mite allergen levels are occasionally unpredictably very low in homes with risk factors for high levels.

Allergens↗
PubMed2004

Low frequency of positive skin tests in asthmatic patients infected with Schistosoma mansoni exposed to high levels of mite allergens.

Helminthic infections and allergic diseases are highly prevalent in many parts of the world. Although skin reactivity to indoor allergens is decreased in subjects from helminthic endemic areas, the degree of exposure to mite allergens has not yet been investigated in these areas. This study evaluated the association between exposure to dust mites and skin reactivity to mite allergens in subjects with a history of wheezing in the last 12 months selected from a rural endemic area for schistosomiasis (group I, n = 21), and two non-Schistosoma mansoni endemic locale, a rural area (group II, n = 21) and a urban slum area (group III, n = 21). All subjects were evaluated by skin prick tests with mite allergens, and for total and specific immunoglobulin E (IgE) against dust mites, antibodies for S. mansoni, and for intestinal parasites. Dust samples from each subjects' home were quantified for mite allergen and species of the mite identification. Except for S. mansoni infection which was more prevalent in group I than in groups II and III (p < 0.0001), the prevalence of intestinal parasites, and total and specific IgE levels were similar for all groups. Despite the levels of mite allergens and specifically to Der p 1 detected in dust samples of subjects home from all three areas, the frequency of positive skin reactivity to mite antigens was significantly lower (19.0%) in subjects from group I relative to group II (76.2%) and group III (57.1%; p < 0.001). This result suggests that S. mansoni infection could modulate the immediate hypersensitivity skin response to mite allergens in highly exposed subjects.

Adolescent↗
PubMed2006

Dust mite species and allergen concentrations in beds of individuals belonging to different urban socioeconomic groups in Brazil.

BACKGROUND: Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis dust mites are among the most important agents of hypersensitivity reactions in human beings. However, a role of other mites in the etiology of these reactions has not yet been excluded. OBJECTIVES: To investigate the nature of the dust mite fauna and the presence of Der p 1 (allergen 1 of Dermatophagoides pteronyssinus) and Blo t 5 (allergen 5 of Blomia tropicalis) on beds used by individuals with different socioeconomic backgrounds in Salvador, a major Brazilian city and to investigate possible associations of mite frequencies and allergen levels with (a) season of the year, (b) housing characteristics, (c) bed cleaning behaviors that could affect mite densities, and (d) allergy history. METHODS: Dust samples were collected from 459 beds of 101 residences from two groups with different socioeconomic levels (hereafter called wealthy and poor groups) in the city of Salvador, Brazil, for the identification of mite species and determination of Der p 1 and Blo t 5 levels. History of allergy was collected using the ISAAC phase I questionnaire. RESULTS: Eighty nine percent of the beds analyzed harbored at least one mite species. B. tropicalis was found in 71.8%, D. pteronyssinus in 39.9%, Cheyletus sp. in 33.9%, and Gohieria fusca in 21.1% of the beds. B. tropicalis was found with a similar frequency in beds of the two socioeconomic groups; D. pteronyssinus was found more frequently in the beds of the wealthy than of the poor group, whereas the reverse was observed with G. fusca. The concentrations of Der p 1 and Blo t 5 allergens exceeded the cut-off for sensitization of 2 microg/g of dust in 94.0% and 69.3% of the wealthy and poor group beds, respectively. No associations were found between history of allergy and mite species or between history of allergy and the concentrations of mite allergens. CONCLUSIONS: The observation of B. tropicalis and D. pteronyssinus as the most frequently found mites is consistent with previous reports from tropical regions. The higher frequency of G. fusca in beds of individuals from the poor group than those from the wealthy group could be a consequence of different bed cleaning behaviors between the two groups.

Allergens↗
PubMed2003

Serum immunoglobulin E against storage mite allergens in dogs with atopic dermatitis.

OBJECTIVE: To determine the prevalence of serum IgE against the storage mites Acarus siro, Blomia tropicalis, and Tyrophagus putrescentiae in a population of dogs with atopic dermatitis. SAMPLE POPULATION: Sera from 84 dogs with atopic dermatitis residing in various regions of the United States and Europe. PROCEDURE: Immunoblotting of sera from atopic dogs was used to identify proteins in mite extracts that bound IgE. RESULTS: 94% of the dogs had serum IgE against proteins in extracts of 1 or more of the storage mite species. Ninety-five, 92, and 89% of the storage mite-sensitive dogs had serum IgE against proteins in extracts of A siro, B tropicalis, and T putrescentiae, respectively. Eighty-two percent had serum IgE against at least 1 protein in all 3 species. Most of the major allergens had molecular weights > 80 kd. A greater percentage of the dog sera had IgE against storage mite proteins, compared with proteins of the house dust mites Dermatophagoides farinae and D pteronyssinus. CONCLUSION AND CLINICAL RELEVANCE: Many dogs with atopic dermatitis have serum IgE against many allergens of storage mites. Most of these allergens, like allergens of dust mites, had molecular weights > 80 kd. Storage mite sensitivity in dogs may be as important, if not more important, than dust mite sensitivity.

Acaridae↗
PubMed2004

Sensitization to the storage mite Tyrophagus putrescentiae in urban population of Upper Silesia (Poland).

Exposure to indoor allergens, especially dust mites has been recognized as a risk factor for sensitization and allergy symptoms that in extreme conditions could develop into asthma. To determine specific antigens responsible for allergy in patients positive for mite allergy skin tests whole protein extracts from the cultured mite species Tyrophagus putrescentiae [TP], and from their excrements were obtained. The proteins were fractionated by SDS PAGE and identified by Western blot. The patient antibodies against particular antigens were identified in serum IgE fraction using anti-human anti-IgE monoclonal antibody. Western blot analysis revealed differences in reactivity of sera from patients positive for standard mite allergy skin tests with fractionated mite antigens. A total of 17 of 30 sera (56.7%) from patients positive to skin tests showed specific cross reactivity with antigens isolated from extracts of TP. The results revealed that 12 out of 30 tested sera (40.0%) reacted specifically with new antigens identified as protein fractions of extracts from excrements of TP. When assessing mite allergen reaction using mixture of mite proteins the results of the test are not satisfactory for determining the antigen causing patient allergy. The results obtained from studies reported here indicate significant discrepancy between the so called standard allergy skin test and what the patient is actually sensitive to. Also, a new class of immunizing protein of about 25 kDa has been identified in excrements from TP reacting with IgE from patients showing allergy to other mite extracts. A total of 4 of 30 sera (approx. 13.3%) from patients positive to skin tests showed specific cross reactivity with antigens isolated from mite excrements rather than from mite whole extracts.

Acaridae↗
PubMed2005

An update on oral anaphylaxis from mite ingestion.

OBJECTIVE: To review systemic reactions due to the oral ingestion of mites. DATA SOURCES: We performed a MEDLINE search of peer-reviewed research articles published between 1993 and 2004 relevant to the subject of anaphylactic reactions to mite-contaminated foods. STUDY SELECTION: Recent studies that emphasized the potentially life-threatening nature of anaphylactic reactions, responsible foodstuffs and mites, populations at risk, and pathogenesis were selected for inclusion in this review. RESULTS: Although relatively few new cases of oral mite anaphylaxis are reported in the literature, we speculate that this clinical condition is occurring more frequently than realized in many geographic locations, and only the suspicion of an informed physician can contribute to its diagnosis and prevention. Oral anaphylaxis from mite-contaminated foods may be lethal if not promptly recognized and treated, and some preventive measures may be helpful for individuals at risk. Frequent cross-reactions among domestic, storage, and phytophagous mites explain the increased risk of oral mite anaphylaxis in sensitive patients living in both urban and rural areas. The enzymatic activity of some mite allergens contributes to the pathogenesis of this syndrome by means of mucosal damage and enhanced allergen absorption through the oral route. CONCLUSIONS: Oral mite anaphylaxis is a severe, potentially lethal allergic condition that occurs in many countries and is frequently undiagnosed. Early recognition may lead to the implementation of simple prophylactic measures in at-risk populations of allergic patients.

Allergens↗
PubMed1993

Antibody development against northern fowl mites (Acari: Macronyssidae) in chickens.

This study reports the development of an antibody against protein(s) from the tissue of the northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Northern fowl mite proteins were obtained by affinity chromatography and used for immunization. Western blot analysis identified proteins that were reactive with sera from birds immunized with the antigen; this indicated that serum antibodies against the northern fowl mite had been produced. Chickens that had been immunized or infested, or both, with the northern fowl mite produced sera that were reactive with a 100 kilodalton (kD) protein. The response was greater if the chicken had been immunized with the antigen and infested with the northern fowl mite. Experimentally immunized and infested chickens experienced limited decreases in the levels of northern fowl mite infestation. Survival of bloodfed mites after ingestion of the immune chicken blood was assessed in an in vitro feeding study using blood-filled parafilm sacs; minor differences in northern fowl mite feeding tendencies were noted. The chickens developed antibodies to the northern fowl mite proteins, but this immunity did not decrease the infestation level or in vitro feeding.

Animals↗
PubMed1999

Feather and nest mites of two common resident birds in two ecologically different Egyptian governorates.

The study of the role played by birds in the distribution of various bacterial, viral and parasitic infections is increasingly from year to year, taking into consideration the flying ability of birds and their migration for food and vital processes. Two of the common Egyptian resident birds, house sparrow (Passer d. niloticus) and laughing dove (Streptopelia s. aegyptiaca) were chosen to study their mite fauna. The overall mite index was 4.74 on the house sparrow and 7.22 on the laughing dove. As to mites, a total of 31 species belonging to 23 genera, 17 families and 3 suborders were collected. The common mites on both types of birds were 22 species. Three species only on house sparrow, and six species only on laughing dove. The house sparrow served host for 25 mite species and the laughing dove served host for 28 mite species. The infestation rates of mites on house sparrow ranged between 1.11% to 23.33% and 0.21% to 34.54% in Sharkia and Qalyobia governorates respectively. For laughing dove, the mite infestation rates ranged between 0.82% to 50% and 3.45% to 55.17% for both governorates respectively. Some of the collected mites have medical and/or veterinary importance. The whole results were discussed.

Animals↗
PubMedDate not supplied

Assessment and control of house dust mite infestation.

Most allergens of the house dust mite (Dermatophagoides pteronyssinus and Dermatophagoides farinae) are carried by the mite excreta rather than by the mites themselves. A method of assessing the concentration of mite excreta in dust (the Acarex test) is described. The effects of Acarosan products, whose active ingredient is solidified benzyl benzoate, on mites and mite excreta were evaluated. Over a period of three years, three to four applications of Acarosan effectively destroyed mites in carpets, upholstery, and mattresses, as assessed by the measure of mite excreta and a count of live mites.

Allergens↗
PubMed2004

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.

Allergens↗
PubMed1998

Regulatory action criteria for filth and other extraneous materials. II. Allergenic mites: an emerging food safety issue.

Four species of food-contaminating mites have recently been reported to have caused IgE-mediated allergic reactions, including anaphylaxis, in persons who consumed mite-contaminated foods. The mite species are the American house dust mite, Dermatophagoides farinae Hughes (Acarina: Pyroglyphidae); the scaly grain mite, Suidasia sp. prob. pontifica Oudemans (Acarina: Suidasiidae), an acarid mite, Thyreophagus entomophagus Portus & Gomez (Acarina: Acaridae); and the mold mite, Tyrophagus putrescentiae (Schrank) (Acarina: Acaridae). Allergenic mites are an emerging food safety issue as ingested allergens in mite-contaminated food.

Animals↗
PubMed1986

Guanine as a hygienic index for allergologically relevant mite infestations in mattress dust.

Since guanine is not only an essential constituent of vital nucleic acids, but also the main end product of nitrogenous waste excretion in arachnids, it is a potential candidate for a hygienic index for mite activity in house dust. The public health significance of these mites is based on their production of allergen in the home environment. In 101 mattress-dust samples, total number of mites and guanine content were positively correlated. The hygienic standard of 10 mites per 0.1 g dust (as derived from Danish investigations) was met in all samples with less than 0.06% guanine in the dry dust. Where the guanine content was more than or equal to 0.25% in the dry dust, mite numbers were higher than 10 mites per 0.1 g dust in 43 of the 44 samples. The three different groups (negligible mite content, possibly allergologically relevant mite concentration and allergologically unhygienic mite situation) could be easily discriminated on the color scale. The guanine-AZO-dye reaction in vacuum cleaner dust is a strong and promising candidate for an allergologically relevant hygienic index in the home.

Allergens↗
PubMed1998

Electrostatic charge characteristics of Der p1 allergen-carrying particles and the house dust mite dermatophagoides pteronyssinus.

Control of the house dust mite allergen has received considerable attention owing to its importance in some allergic diseases. One aspect of dust mites and their allergen-carrying faecal particles that has not been reported on, which may have allergen control applications, is the electrostatic charge they carry in the natural environment. To promote tribo-electric charging, household dust containing dust mite allergen and live house dust mites are separately agitated while in contact with either polypropylene, nylon or earthed metal. The charged dust and mites are subsequently subjected to electrostatic separation and collection. Results for concentrations of the house dust mite allergen, Der p1, indicate that, when subjected to nylon, Der p1 carrier particles appear to be predominantly positively charged. Similarly, when subjected to polypropylene, Der p1 carrier particles also appear to be positively charged. Reduction of excess free charge by agitation against earthed metal does not appear to affect the observed charging characteristics, indicating that the positive charge may be bound or inherent in the Der p1 carrier particles. In contrast, house dust mites exposed to nylon appear to be generally charging negative, whereas mites exposed to polypropylene appear to be charging positive. The observed electrostatic characteristics of the mites and Der p1 carrying particles will be useful in the future development of electrostatic allergen control methods.

Allergens↗
PubMed2005

Diapause incidence in the two-spotted spider mite increases due to predator presence, not due to selective predation.

We recently reported evidence for increased diapause incidence in the spider mite Tetranychus urticae in presence of the predatory mite Typhlodromus pyri. This effect may arise from (1) selective predation on non-diapause spider mites, (2) predator-induced diapause in spider mites, or (3) both. Using a different strain of T. urticae, we first recovered increased diapause incidence in association with predators. Then, we tested for selective feeding in two-choice experiments with equal numbers of non-diapause and diapause spider mites. We found that the predatory mite had a significant preference for the latter. This indicates that increased diapause incidence in association with predatory mites is not due to selective predation. Therefore, predator-mediated physiological induction of diapause seems a more likely explanation. The cues leading to induction appear to relate to the predators, not their effects, since predation simulated by spider-mite removal or puncturing did not significantly affect diapause incidence. Why spider mites benefit from this response, remains an open question.

Adaptation, Physiological↗
PubMed2005

How predatory mites find plants with whitefly prey.

We investigated the searching behaviour of two species of predatory mites, Typhlodromips swirskii (Athias-Henriot) and Euseius scutalis (Athias-Henriot), both known to feed on immature stages of the whitefly Bemisia tabaci Gennadius. When released in a greenhouse inside a circle of cucumber plants that were alternatingly clean or infested with immature whiteflies, the mites took several days to find plants. Both species were recaptured significantly more on plants with whiteflies. This suggests that the mites are able to discriminate between plants with and without whiteflies. The predators may either have been attracted to plants with whiteflies from a distance or arrested on plants with whiteflies. Typhlodromips swirskii that had previously fed on whitefly immatures on cucumber leaves were significantly attracted by volatiles from cucumber plants with whiteflies in a Y-tube olfactometer. This suggests that the mites use volatile cues to discriminate between infested and clean plants. However, this response waned rapidly; if predators, experienced as above, were starved for 3-4 h in absence of cucumber leaves, they no longer preferred volatiles of infested plants to clean plants. Furthermore, T. swirskii that had no experience with immature whiteflies on cucumber plants also did not prefer odours of infested plants to those of clean plants. Because the release experiment with this species in the greenhouse was done with inexperienced predators, this suggests that the aggregation of mites on plants with whiteflies was mainly caused by differential arrestment of mites on plants with prey and clean plants. For T. swirskii, this was in agreement with the finding that the fraction of predators on plants with prey increased with time to levels higher than 70%. A less clear trend was found for E. scutalis, for which the fraction of predators on plants with prey stabilized soon after release to levels from 54-70%. Hence, the predatory mites may find plants with prey by random searching, but they are subsequently arrested on these plants. An earlier study showed that 87% of all whiteflies released in a set-up as used here were recaptured within 1 day. Hence, the effectiveness with which predatory mites locate plants with whiteflies is low compared with that of their prey. We expect this to generate spatial patterns in the dynamics of predator and prey and this may have consequences for biological control of whiteflies with predatory mites.

Animals↗
PubMed2005

Mite allergens.

There is an increasing awareness of the health implications of mite sensitivity, as it is closely related to asthma. Mite allergy constitutes a complex worldwide problem, with sanitary and economical implications. Not only are mite species present in house dust, producing potent allergens, but other, less studied species are also responsible for significant allergic reactions in occupational settings. In this review, we focus on the growing number of mite species that are implicated in allergic cutaneous and respiratory diseases in humans. Mite allergy is not restricted only to the human "indoor" environment, because numerous reports clearly demonstrate that many species that can induce sensitization and symptoms are encountered in occupational settings. An important component of allergy research is the evaluation of the allergenic cross-reactivity to verify to what extent different mite species have unique, species-specific, or cross-reactive allergens. The results of these investigations have important clinical consequences for the diagnosis and treatment of allergic diseases. Internationally standardized mite extracts are needed to compare sensitization rates around the world and clearly establish risk factors associated with sensitization and asthma. In spite of recent controversial results, a significant reduction in the exposure to mite allergens continues to be an important challenge and one of the main goals in the treatment of mite-induced respiratory symptoms. In many cases, this reduction must be achieved in the workplace as well as in the home environment.

Agriculture↗
PubMed1978

IgE antibody response to mite antigen in the mouse. Suppression of an established IgE antibody response by chemically modified antigen.

The antibody response to mite antigen in several mouse strains was studied. BALB/c, CBA, C3H/He, and C57B1 strains showed good responses against mite antigen. The AKR strain, on the other hand, showed a relatively poor response. When BALB/c mice were immunized with DNP-mite conjugate in aluminum hydroxide gel (alum), anti-DNP IgE antibody and IgG1 antibody were induced. When these mice were boosted with mite antigen alone in alum, both anti-mite IgE antibody and IgG1 antibody were induced, although these antibodies were not observed after the first immunization. Both IgE antibody responses were high and persistent. Mite antigen was denatured by alkylation and reduction in the presence of 8 M urea. Native antigen remaining in the chemically denatured antigen was removed by an immunoadsorbent method. The modified mite antigen could stimulate the carrier-specific helper cells, at least when it was injected with alum. It was also found that repeated injections of the modified mite antigen resulted in the suppression of an established IgE antibody response against mite antigen. These findings suggest possible clinical application for hyposensitization therapy.

Animals↗
PubMed1987

Seasonal variation in dust mite and grass-pollen allergens in dust from the houses of patients with asthma.

In order to study seasonal variation in dust-mite allergen, we obtained dust samples from bedding, carpet, and/or sofas in 12 houses in central Virginia, monthly, for 1 year. The houses included those of nine patients with asthma of whom six were allergic to dust mites. Dust samples were assayed with an inhibition radioimmunoassay for mite allergen that detects cross-reacting determinants on Der f and Der p I from Dermatophagoides farinae and D. pteronyssinus, respectively. The results are expressed as micrograms of antigen P1 equivalent (AgP1Eq). The results demonstrate that large seasonal variations in allergen, i.e., more than twentyfold, can occur in dust from all sites and are not restricted to the houses of allergic patients. However, dust from some sites, particularly sofas, remained "high" (greater than 10 micrograms AgP1Eq per gram), whereas dust from other sites remained "low" (less than 1 microgram AgP1Eq per gram) throughout the year. Levels of mite allergen generally started to rise in July about 1 month after the rise in humidity. In August to December, the mean levels of AgP1Eq in house dust were highly significantly increased relative to April to May. In keeping with this finding, in 31 of 37 sites, the highest level for the year was observed in August through December. In four sites, mite bodies were counted, and the numbers increased sharply in June to July; however, they decreased in September in parallel with falls in humidity but several months before the fall in mite allergen. Ryegrass-pollen allergen in 12 sites was also assayed in house dust, and pollen-allergen levels demonstrated a sharp increase in May or June that fell back to preseason values within 2 months. Dust was also obtained from the houses of 50 patients with acute or severe asthma. The results on these samples suggest that mite-allergic patients are more likely to have attacks in the fall at a time when their houses have greater than 10 micrograms AgP1Eq per gram of dust. The magnitude of changes observed seasonally within individual houses and of differences between houses within a close geographic area suggests that interpretation of the relationship between allergic symptoms and mite-allergen exposure will require measurement of mite-allergen levels in individual houses.

Asthma↗