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PubMed1991

[The epidemiology of allergy to house dust mites].

Currently, several studies show that sensitivity to mites is frequently found in the general population and in people suffering from respiratory allergic disorders. Thus 5 - 30% of the general population has positive skin tests whilst such sensitivity is found in 45 - 85% of asthmatic subjects. Certain studies have tried to establish a threshold of allergenicity beyond which the respiratory manifestations in allergic subjects became important. It seems after different studies that a threshold of 10 micrograms of antigen group I (the sum of the major antigens greater than Der p 1 and Der f 1) per gram of house dust may be a threshold beyond which the risk for the appearance of respiratory manifestation and in particular those of asthma in allergic subjects may be important. Moreover other studies tried to achieve a better understanding of the role of environmental conditions which favour the development of the mites. No or very few mites can develop if the relative internal humidity is less than 45% for an indoor temperature of 22 degrees C. These levels may be obtained in particular at altitude or in regions where the absolute outdoor humidity is low or the indoors are well heated and well ventilated. Epidemiological studies carried out in the last few years show that the relation between allergic respiratory mites disorders again show the frequency of diseases linked to the mites and the major influence of the environment as well as the idea of a tolerable allergenic threshold.

Animals↗
PubMed1990

Mite dermatitis other than scabies.

Most mites are small, have mouth parts capable of puncturing, feed on tissue fluids, have a high reproductive rate, and are found in all habitats, including human skin. Mites are important causes of cutaneous diseases and are vectors of important infectious diseases. Mite bites should be considered whenever any unexplained cutaneous eruption is presented to the dermatologist. A knowledge of the biology of the mites that can attack humans is important when taking a history and for identifying the etiology. Treatment of the dermatitis is symptomatic, with a cure depending on the identification and eradication of the causative mite.

Animals↗
PubMed1990

[Seasonal changes in the population count of allergenic mites (Acariformes, Pyroglyphidae) in the dust of living quarters in the city of Moscow].

The seasonal dynamics of allergenic mite quantity in house dust of three model apartments in Moscow has been observed during three years. Two periods of increase in mites' quantity have been revealed: wintry and summer-autumnal. Mite breeding takes place both in winter and in summer-autumnal period. The quantity variations of allergenic mites are cyclic and have individual traits peculiar to each population of these mites.

Allergens↗
PubMed1990

[Seasonal variations in house dust mite allergens--significance for children with allergy].

Allergenic proteins of the house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae and their major allergens Der p I and Der f I are one of the most significant environmental factors which may facilitate sensitization and allergic airway disease in childhood. In order to measure seasonal variations of mite allergen exposure, we collected mattress dust samples monthly in 13 homes over a period of 1 year. Der p I and Der f I were determined with a sandwich type ELISA. Mite allergen levels were significantly lower from January-June than from July-December (p less than 0.05) which was mostly due to Der p I variations. Only in 6 of the studied homes seasonal variations in mite allergen concentrations according to seasonal variations in outdoor humidity could be observed. In 7 homes mite allergen exposure stayed constant and seemed to depend only on indoor climate factors.

Allergens↗
PubMed1990

Dermatophagoides and storage mites: statistical analysis of RAST results.

R.I.A. dosages of specific IgE antibodies to Dermatophagoides pteronyssinus, Dermatophagoides farinae (house dust mites), Acarus siro, Lepidoglyphus destructor, and Tyrophagus putrescentiae (storage mites) in 467 unselected patients were statistically analyzed. A significant noncorrelation between specific IgE antibodies to storage mites and those to house dust mites has been found, suggesting that storage mites have their own allergenic specificity.

Allergens↗
PubMed1989

[Sensitization to house dust mite allergens: diagnosis--therapy].

The 2 closely related house dust mites, D. pteronyssinus and D. farinae seem to be of major allergenic importance in the house dust. The faeces particles, in particular, contain allergenic material in a concentrated form. Practicable control measures, such as chemicals, cleaning, ventilation and temperature regulation, have been able to reduce the number of mites in houses to some extend, and, in general, the clinical effect has been limited. The immunotherapy could be appropriate for this type of allergy, and, in fact, in some studies such treatment has proved to be of some effect. In our own experience, control measures to reduce the mites, antiallergic drug therapy and controlled holidays in a mite free climate allow to reduce by far the mite allergen symptoms. In addition the immunotherapy could be of some success depending on the allergens, the doses of the allergen extract given and the duration of the therapy. It is still an open question, whether the therapeutic effect of the immunotherapy is of long duration after the immunotherapy has been finished.

Allergens↗
PubMed1989

[Measurement of IgE, IgG1 and IgG4 antibodies against mite Sephadex fractions and purified allergens by means of enzyme-linked immunosorbent assay].

Mite antigens (Dermatophagoides farinae) were fractionated by a Sephadex G-200 column and their reactivities with IgE, IgG1 and IgG4 antibodies were investigated with enzyme-linked immunosorbent assay (ELISA). High IgE antibody values were observed in fractions with low molecular weight (allergenic part), while high IgG1 and IgG4 antibody values were observed in fractions with high molecular weight. High IgG4 antibody values to crude mite extract and fractions with high molecular weight were detected in individuals who had received immunotherapy. However, IgG4 antibodies directed to allergenic part were found in only one out of 12 sera tested. IgG4-ELISA using DF1 (major allergen of Dermatophagoides farinae) as antigen was also performed. In the group treated with mite, significant IgG4 antibody levels were detected in only one out of 13 sera tested. In the group treated with house dust, significant IgG4 antibodies were detected in only one out of 12 sera tested. Patients who showed high IgG4 antibody responses to crude mite extract and to high molecular weight did not show responses to allergenic part and DF1. The only case who showed positive IgG4 responses to allergenic part also reacted with DF1. Those results suggest that IgG1 and IgG4 antibody values in ELISA using crude mite extract as antigen do not reflect major allergen-specific antibody values. The importance of the use of partially purified antigens in measuring major allergen-specific IgG4 antibodies was also suggested.

Allergens↗
PubMed1986

[Seasonal changes in the count of mites of the family Pyroglyphidae in houses in the city of Cheboksary].

The results of human dwelling houses surveying for the presence of home dust mites and study of seasonal changes of their quantity in the town of Cheboksary are given. It has been found that the old wooden houses are inhabited by mites, in modern blocks of flats they are met rather seldom. The quantity of alive mites is maximum in September-October. The common number of mites is the greatest in December-January although the quantity of alive mites at this time is only 6.8%.

Animals↗
PubMed1988

House dust mites in university dormitories.

As no published data was available, dust was collected from 102 university student dormitory rooms and 33 were selected on a random basis for analysis. Mean dust per dormitory room was 4.47 g of coarse, 0.96 g of fine, and a 24-hour sedimented volume of fine dust of 6.90 mL. The mean number of mites was 63/g of coarse dust, and 240/g and 36/mL of fine dust. They were identified as D. pteronyssinus (D.p.), 81.9%; D. farinae, 11.2%; and Cheyletus, 4.7%. Fifteen samples from homes were controls. Mean values were 0.60 g of coarse dust, and 0.20 g and 2.3 mL of fine dust. Mites numbered 985/g of coarse, and 3409/g and 244/mL of fine dust. They were D.p., 87.2%; D. farinae, 3.0%; Cheyletus, 3.7%; and Euroglyphus, 1.6%. Differences between dormitories and homes in amount of dust and number of mites were significant at P less than .001. Dust and mites were significantly less in dormitories with linoleum than those with carpets (P less than .05 and .01, respectively). In conclusion, university dormitories have significantly less mites than homes despite a greater amount of dust harvested.

Animals↗
PubMed1986

Allergenic and immunogenic components of house dust mite, Dermatophagoides farinae.

The house dust mite, Dermatophagoides farinae, was fractionated by a Sephadex G-200 column. Its allergenic (IgE-reacting) and immunogenic (IgG-reacting) components were investigated. By means of skin test, the molecular weight (MW) of major allergenic components of mite was found to be approximately 9,000 to 21,000 daltons. Immunogenic components were investigated by enzyme linked immunosorbent assay using each fraction as an antigen and mice plasma and human serum as antibodies. With mouse plasma, high IgG antibody titers were observed in fractions that contained the part of the mite with high MW (greater than 150,000). With human sera, high IgG antibody titers were observed in fractions that contained the part of the mite with MW more than 30,000. Heterogeneity of human IgG antibody responses against mite antigen was also suggested.

Allergens↗
PubMed1986

Artificial feeding of northern fowl mites, Ornithonyssus sylviarum (Canestrini and Fanzago) (Acari: Macronyssidae), through membranes.

A new device and technique are described for the in vitro feeding of northern fowl mites, Ornithonyssus sylviarum (Canestrini and Fanzago). The device consisted of a glass cylinder 25 mm in length and in outside diameter, capped with a chick skin membrane at one end and a snap-cap with a wire cloth window at the other end. Maximum feeding by northern fowl mites on warmed heparinized chicken blood occurred after 60 min and at a blood temperature range of 36-42 C. Skin membranes prepared from 1-wk-old chicks gave significantly higher feeding rates than those from 4-wk-old chicks, but unfrozen skins and skins frozen up to 4 wk were equally effective. Also, mites fed equally well through white leghorn and broiler chick skin membranes. About 80% of northern fowl mites fed. The in vitro technique described simplifies the approach to studies of northern fowl mite biology and physiology.

Animals↗
PubMed1983

[Comparative evaluation of the specific activity of different types of allergens from Dermatophagoides pteronyssinus mites].

The specific activity of different kinds of allergens prepared from dermatophagoid mites has been studied by the method of the indirect mast cell degranulation and the method of changing the volume of cerebral glial cells in patients with the atopic form of bronchial asthma. In cases of sensitization to mites the presence of reagin and precipitin antibodies has been revealed. Allergens prepared from the mite medium and directly from mites have been found to possess almost the same specific activity. Changes in the volume of glial cells have been found to serve as a sensitive test revealing the specific activity of mite allergens.

Allergens↗
PubMed1984

Recognition of two Dermatophagoides pteronyssinus-specific epitopes on antigen P1 by using monoclonal antibodies: binding to each epitope can be inhibited by serum from dust mite-allergic patients.

Monoclonal antibodies were raised against Antigen P1, the major allergen of the house dust mite (Dermatophagoides pteronyssinus). The majority were Antigen P1 specific, isotype IgG1, and did not react with a comparable D. farinae allergen. These antibodies bound 38 to 50% of 125I Antigen P1 in antigen-binding assays (titer greater than or equal to 1/1,000,000), and the quantities of IgG antibody in ascites were 2 to 4 logs greater than those in polyclonal mouse antiserum or in serum from a mite-allergic patient. Two IgM antibodies showed weak binding to Antigen P1 but reacted strongly with D. pteronyssinus in enzyme immunoassay (titer greater than or equal to 1/100,000). Assessments of the specificity of the IgG antibodies by using two inhibition radioimmunoassays suggested that they were directed against two different epitopes. Antibodies 10B9 F6 and 5H8 C12 were purified by preparative isoelectric focusing (isoelectric points of pI 6.25 and 7.4, respectively) and radiolabeled with 125I. Cross-inhibition experiments, using ascites dilutions to inhibit binding of each radiolabeled antibody to Antigen P1, confirmed that these antibodies recognized two distinct epitopes. Analysis of antibodies from 39 clones/hybrids showed that the majority were directed against the same epitopes as either 10B9 F6 or 5H8 C12 (3 out of 39 [8%] and 29 out of 39 [74%], respectively). None of the monoclonal antibodies significantly inhibited (greater than 10%) human IgE binding to Antigen P1 in the radioallergosorbent test. However, 12 of 14 sera from mite allergic patients inhibited binding by the monoclonal antibodies. One serum from a mite-allergic patient inhibited binding of both 10B9 F6 and 5H8 C12 by greater than 85% and showed parallel inhibition curves. The results suggest that these monoclonal antibodies could be used to assay Antigen P1 in both D. pteronyssinus and house dust extracts. It should also be possible to use monoclonal antibodies in inhibition assays to define the antigenic/allergenic determinants recognized by human IgG and IgE antibodies on this mite allergen.

Allergens↗
PubMed1983

Sensitization in a grain handler to the storage mite Lepidoglyphus destructor (Schrank).

Allergy to one of the most common Canadian storage mites. Lepidoglyphus destructor, was demonstrated in a grain worker by immediate skin testing and inhalation challenge. The frequency of sensitization to this mite was found to be 12% in 100 asthmatics by skin testing. In 4% of these asthmatics sensitization to another storage mite, Acarus siro, was found, all of whom were also sensitized to L. destructor and the house dust mite, Dermatophagoides farinae. There was a significantly higher proportion of asthmatics sensitive to the storage mites and to fungi who had a history of exposure to grain compared to those who did not.

Asthma↗
PubMedDate not supplied

[Factors influencing the house dust mite population IV. Altitude].

A study has been carried out on house-dust mites present in the buildings of 3 towns in Catalunya (Spain), with different altitudes: Reus (altitude, 76 m); L'Ametlla (altitude, 321 m); and Puigcerdá (altitude, 1.202 m). The period studied was between october, 1975 and september 1976. From this study, a negative correlation has been observed between the number of mites in house dust and the altitude of the town. This supports the results obtained by other authors. The decrease in the number of mites with increases in altitude is due to a decrease in the number of mites belonging to the Pyroglyphidae family. This family was present in all samples of house-dust studied, and generally in a greater number than other groups of mites. Of the three species of Pyroglyphidae more frequently present in house dust (Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei), D. pternyssinus was the most abundant as well as the most affected variations of R.H and temperature resulting from the variations of the altitude. D. farinae and E. maynei were found in low levels suggesting inadequate conditions of temperature and R.H. in the houses studied. Even if E. maynei was the most abundant species in Puigcerdá, this is due more to the decreased incidence of D. pteronyssinus than to an increase in the number of E. maynei.

Altitude↗
PubMedDate not supplied

[Ecological study of Pyroglyphides mites in house dust in the Grenoble area. A qualitative approach and incidence of various parameters: seasons, altitude, temperature and relative dampness in their multiplication].

This study concerns the analysis of 70 samples of dust mites taken periodically from 13 sample areas or mattresses at different altitudes. It shows the presence of Pyroglyphid mites in all the mattresses studied. Four species were found: Dermatophagoides pteronyssinus, Dermatophagoides farinae, Euroglyphus maynei and Dermatophagoides evansi. From a quantitative point of view, the statistical analysis of the results obtained allows the following conclusions to be drawn: -- All the Pyroglyphids (adults and young) undergo seasonal fluctuations at low, middle and high altitude. In the plains and at middle altitude these mites have a seasonal maximum and minimum. At high altitude only the seasonal maximum can be determined. -- The number of Pyroglyphids found is much higher in the plaine than at middle altitude and at middle altitude than at high altitude. The influence of altitude can be demonstrated with certitude. -- The conditions of temperature and relative dampness most favourable to the multiplication of mites are found in the plaine. At middle and high altitude these conditions are only met in summer. In flat country the statistical analysis allows us to show the existance of a correlation between the rate of dampness and the number of Pyroglyphids, and more specially, between the dampness rate and Dermatophagoides farinae, a predominant species at this sampling area. At middle and high altitude such a correlation cannot be shown clearly. At the three altitudes considered, no correlation can be established between the temperature and the number of Pyroglyphid mites found.

Altitude↗
PubMed1994

Isolation of three species of mites from house dust of atopic dermatitis patients in Qualyobia Governorate, Egypt.

Dermatitis or inflammation of the skin caused by an outside agent, is a condition with many causes. It may result from direct irritation of the skin by a substances (chemical or insecticide) or it may be an allergic reaction to a particular substance that has been in contact with the skin as soap or detergent or insect urticating hairs; injected as insect saliva or faeces or sting or taken by mouth as food or drug. In general, treatment of dermatitis depends mainly upon the cause. In the present study, three species of mites were isolated from the dust collected from houses of atopic dermatitis patients. These mites were Dermatophagoides pteronyssinus, Ornithonyssus bacoti and Haemogamasus pontiger. The former species was the predominant one which is known to produce the most potent allergen. It was concluded that house dust mites are one of the aetiological factors of atopic dermatitis and that genera of mites other than Dermatophagoides may be considered as allergen in house dust mites.

Animals↗
PubMed1994

Asthma in Gaza refugee camp children and its relationship with house dust mites.

Three hundred asthmatic children aged 3 to 15 years, and 100 age-sex-neighborhood matched controls, were studied for environmental risk factors for asthma during 1986 to 1987. In 98% of the asthmatic patients, exposure to house dust aggravated the symptoms. In 97% of the cases, the symptoms were more severe at home; in more than 50%, the symptoms persisted throughout the year. Significantly more cigarettes were smoked in the homes of the allergic children than in the control homes. House dust samples from homes of 20 asthmatic and 20 nonasthmatic children were examined for the presence of house dust mites. Twelve species of mites were identified, of which Dermatophagoides pteronyssinus, the most prevalent (97%), was found in all samples examined. The average number of mites per gram dust was 447 in homes of children with asthma, and 399 in homes of controls. Although dust and mites seem to be the most important factors causing allergies in Gaza and most of the children are exposed to large numbers of mites in their homes, it appears that those who are genetically predisposed and who are exposed to environmental tobacco smoke are at greater risk for allergic symptoms.

Adolescent↗