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PubMed1995

Reactivity to intradermal injections of extracts of house dust and housedust mite in healthy dogs and dogs suspected of being atopic.

Fifty dogs underwent intradermal allergy testing with housedust mite and house dust extracts, using concentrations recommended by the manufacturer. Twelve dogs (group I) were healthy dogs obtained from a pound; 12 dogs (group II) were healthy, privately owned dogs; 15 dogs (group III) were suspected of being atopic and had had multiple positive reactions to intradermal injections of allergens of specific trees, weeds, grasses, or molds; and 11 dogs (group IV) were suspected of being atopic, but only had had positive reactions to intradermal injections of housedust mite, house dust, and flea antigen extracts. Use of the concentrations of housedust mite and house dust extracts currently recommended for intradermal allergy testing resulted in false-positive reactions in 14 of 24 (58%) and 12 of 24 (50%) healthy dogs tested, respectively. Differences in number of dogs with positive reactions or grade of reaction to housedust mite or house dust allergens were not detected between groups of healthy dogs (groups I vs II), between groups of suspected atopic dogs (groups III vs IV), or between healthy dogs and dogs suspected of being atopic (groups I and II vs III and IV). Therefore, clinical importance of positive results of intradermal allergy testing of house dust or housedust mite allergens was equivocal for dogs suspected of being atopic. Threshold concentrations for intradermal allergy testing were determined in 24 healthy dogs (group I and II) by intradermal administration of 5 dilutions each of housedust mite extract and house dust extract.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMedDate not supplied

[Sensitization to house dust mites and juvenile atopic dermatitis].

The etiopathogenetic bases of atopic dermatitis are still much discussed and controversial. Nevertheless most of the Authors agree upon the pathogenetic role of an IgE mediated hypersensitivity mechanisms with respect to many alimentary and/or environmental allergens. We have looked for the IgE mediated sensitization to the house dust mites by means of skin tests (prick) and/or haematic dosage of specific IgE (F.A.S.T.) in a group of 40 children aged less than 6 with atopic dermatitis. We have divided the examined children into three groups according to their age and found out a high percentage of dust mites sensitization in the children of the oldest age group. This datum could give credit to the hypothesis of a pathogenetic role developed by the allergy to dust mites in the keeping of eczematous lesions. From the anamnestic search emerge both the leading role developed by dust mites on the development of allergic breathing pathology in the subjects with atopic dermatitis and the finding out of a settled exordium of breathing manifestations due to dust mites at an older age in comparison with the age in which the cutaneous disease manifests itself. These observations lead us to recommend a very accurate environmental cleaning since the first manifestations of atopic dermatitis prescinding from the checking of a demonstrated IgE mediated house dust mites hypersensitivity.

Age Distribution↗
PubMed1994

Comparison between the Acarex R test and a Der p 1 ELISA for the detection of house-dust mites in the homes of asthma sufferers.

Exposure to house-dust mite allergens in early childhood is an important determinant of the subsequent development of asthma. The Acarex R semi-quantitative test (Noristan) is marketed for use in patients' homes to assess mite levels in house dust. In order to evaluate the reliability of the test in a coastal area where house-dust mites are known to be prevalent, house-dust mite levels were estimated in 119 dust samples obtained from the homes of asthmatic children in a comparative study, by means of the Acarex R test and a Der p 1 enzyme-linked immunosorbent assay (ELISA). A linear regression of the 4 Acarex classes against log Der p 1 revealed a significant correlation (P = 0,0001) but there was a poor correlation between low Acarex R scores and the Der p 1 allergen levels determined by ELISA. Acarex R scores of 2 and 3 were usually associated with Der p 1 levels greater than 10 micrograms/g dust. Our studies indicate that the Acarex R test will identify high levels of mite allergens. Although its application may be limited in coastal areas such as the Cape Peninsula, it may be more useful inland, in climates where house-dust mites are not commonly encountered in all homes.

Allergens↗
PubMed1994

Humidity regulation in the management of asthma patients sensitized to house dust mites.

Substances in the faeces of house dust mites are well-recognized as common allergens in the pathogenesis of asthma. There have been many trials of interventions aimed at reducing mite populations in the home, but most have been uncontrolled, too small, or too short to determine with confidence any beneficial effects. Of those which succeeded, very few used methods which reduced mite populations on a permanent basis. House dust mites are sensitive to humidity. Their geographical distribution is closely correlated to the availability of moisture. Very little work has been done on the effects of reducing humidity in the home environment in the long term, with a view to controlling dust mite populations. Two different methods which might reduce humidities to levels which could successfully reduce dust mite numbers are dehumidifiers, and mechanical ventilation with heat recovery (MVHR). To date there has been no work assessing the effectiveness of dehumidifiers and very little (although promising) work on MVHR. We discuss the potential of humidity control as an adjunct to the clinical treatment of asthma.

Animals↗
PubMed1994

Effect of electric heating carpet on house dust mites.

An electric heating carpet (EHC) that had been especially modified to produce a steady surface temperature of 45 to 50 degrees C was set up in the bedroom of an asthmatic patient, and the density of floor dust mites in this room was compared monthly for 2 years with that in two non-EHC control rooms. When the EHC was used during the mite-growing summer season, the monthly variation in mite density in the EHC room was almost parallel to that in the non-EHC rooms, with a preponderance of floor mites in the non-EHC rooms. In contrast, when the EHC was used during the winter season, the density of floor mites in the EHC room increased as compared with that in the non-EHC rooms, and the ratio of mite density in the EHC room to that in the non-EHC rooms was transiently reversed during this period.

Animals↗
PubMed1993

Effect of economic status on the use of house dust mite avoidance measures in asthmatic children.

To assess the effect of socioeconomic status on compliance with house dust mite avoidance measures, we interviewed the parents of 60 mite-allergic, asthmatic children about mite avoidance. Thirty were of lower socioeconomic status and 30 were of higher socioeconomic status, as determined by the type of insurance. All had previously learned mite avoidance measures at the time of diagnosis. Twenty of 30 lower socioeconomic status parents had removed stuffed toys from the child's bedroom compared with only 12 of 30 higher socioeconomic status parents (P = .07). Twelve of 30 parents in the lower socioeconomic status group had obtained plastic mattress covers compared with 22 of the 30 higher socioeconomic status parents (P = .018). Eighteen parents in the lower socioeconomic status group expressed reasons for not obtaining plastic covers. Nine cited lack of funds, four did not know where to buy them, and four did not think it would help. Of the eight parents in the higher socioeconomic status group that did not obtain covers, six cited inconvenience and two thought it would not help. We conclude that education alone will not ensure compliance with house dust mite controls. Economic factors influence utilization. Access to free or low cost mite-proof pillow and mattress covers may improve asthma care for poor children.

Adult↗
PubMed1993

[Repellent effect of wood odors on mites].

Since mites are known to react to odor, the repellent effect of wood odors on mites was measured with a simple indicative method of mite evasion behavior. This experiment confirmed that the odors of three types of trees including Hinoki (Chamaecyparis obtusa), Pine (Pinusdensiflora) and Cedar (Cryptomeria japonica), had repellent effects on Tyrophagus putrescentiae, Dermatophagoides farinae and D. pteronyssinus, mite specics which are comminly found in houses. The effects of Lauan (Shorea spp.) and Spruce (Picea sitchensis) were less than those of Hinoki, Pine and Cedar in stimulating evasion response. In comparing the evasion behaviors of three species of mites to wood odors, the responses of D. farinae and D. pteronyssinus seemed to be stronger than those of T. putrescentiae. Very little differences in responses between males and females of these mites were seen.

Animals↗
PubMed1993

Mite infestations other than scabies.

Scabies is clearly the primary medical problem involving mites. However, regionally, there is a broad variety of other dermatoses associated with mite exposure, which in some areas vastly exceed the incidence of scabies. Also, scabies is characterized by a cyclical occurrence that is unusual in other mite infestations and mite-associated dermatoses. Many of these have seasonal or regional characteristics, which will be discussed. The clinical aspects of mite infestation will primarily be dealt with, and the basic anatomy and biology of the mites will be ignored.

Animals↗
PubMed1995

Accumulation of house-dust mite (Der-p-1) levels on mattress covers.

Mattresses serve as a large reservoir for house-dust mite antigens and harbour the highest mite levels within the household. Mite reduction measures have previously been shown to be unsuccessful. The effect of mattress covers and acaracides on Der-p-1 levels in the mattresses of 60 patients with mite-allergic asthma was studied. Der-p-1 levels were measured using monoclonal antibodies (ELISA method). Baseline levels were recorded and re-assessed at 8-week intervals over a 6-month period. Patients were randomised into three equal groups. In group A mattresses were treated with Metsan (Snowchem) and benzylbenzoate only; group C had their mattresses covered with mattress covers (Allergy Control Products). Group B was the control group. We were unable to demonstrate any reduction of mite levels in the beds of all 3 groups. In fact all 3 groups demonstrated an increase in Der-p-1 levels over the study period, viz. group A (mean pre: 14.28, post: 34.18 micrograms/g dust); group C (mean pre: 8.26, post: 20.80 micrograms/g dust) and group B (mean pre: 18.21, post 38.47 micrograms/g dust). However, 12 patients in group C had their mattress covers washed in hot water at weekly intervals over a 5-week period at the end of the study. The results demonstrated a significant reduction in mite levels (mean pre: 41.95, post: 26.2 micrograms/g dust; P = 0.027). We therefore conclude that the use of mattress covers per se does not reduce Der-p-1 levels. The regular application of benzylbenzoate and Metsan does not prevent the accumulation of Der-p-1 on mattresses either.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1996

Possible induction of food allergy during mite immunotherapy.

Sera of 17 patients receiving immunotherapy for house-dust mite allergy were tested for IgE antibodies against snail and shrimp. Serum samples were taken at the start of immunotherapy and 14-20 months later. While the average IgE response to mite, Der p 1, and Der p 2 did not alter significantly, the average response to snail showed a significant increase. This included two conversions from negative to strongly positive. These novel IgE antibodies against snail were shown to be cross-reactive with mite. Three patients had a positive RAST for shrimp. For one of them, a strong increase of IgE against shrimp (and snail) was observed. In 2/3 snail/shrimp-positive sera, IgE antibodies against the cross-reactive allergen tropomyosin from mite, snail, and shrimp were demonstrated. A clear IgE response to snail (> 10% binding in a snail RAST) was confirmed by a positive skin prick test (SPT) for 6/10 patients. The two patients with antitropomyosin IgE also had a positive SPT for shrimp, and demonstrated the oral allergy syndrome (OAS) after eating shrimp. The observations in this study indicate that house-dust mite immunotherapy is accompanied by the induction of IgE against foods, including tropomyosin-reactive IgE. Food allergy (OAS) was observed in patients that had IgE antibodies against this cross-reactive allergen. In conclusion, induction of IgE during mite immunotherapy might occasionally cause allergy to foods of invertebrate animal origin.

Allergens↗
PubMed1996

[Impact on the development of extrinsic asthma caused by dust mites exposure, and its sensitization in Jiangsu].

To obtain information on the relationship between dust mites exposure, dust mite sensitization, and the development of extrinsic asthma in Jiangsu province between 1992-1993, a case-control study was carried out. Unconditional logistic regression method was conducted. The results showed that the history of allergy in parents, dust mites exposure, dust mite sensitization, and birth in months with high mite densities were factors which played important roles in the development of extrinsic asthma. The population attributable rate of dust mites exposure was 70.29%. Based on the results, some practical preventive measures were put forward.

Adolescent↗
PubMed1996

[Housedust mite culture medium: an alternative source for the production of allergenic extracts].

House dust mites are the most important source of allergens in the tropical environment, and aqueous whole body extracts of these organisms have wide use in the diagnosis and treatment of allergic diseases. However, it has been reported that mite excretions have a high allergenic activity. Because of this, we have evaluated spent house-dust mite culture medium as an alternative source of allergens from these organisms. We demonstrated that the extraction of allergens from this material is more efficient in alkaline solutions such as ammonium bicarbonate, and when the extraction process is extended to 48 hours. When the purification process is complemented with dialysis and ammonium sulphate precipitation, the toxicity of the extract decreases and its allergenic activity increases. The electrophoretic pattern of proteins of the spent culture medium extract showed bands that bound specific IgE antibodies, but this extract may be deficient in one of the principle allergens of mites, Der pII. The extract stimulates immediate hypersensitivity skin reactions in house-dust allergic patients, and produces RAST inhibitions with their sera. The allergenic activity of this extract is comparable to that of the 1st. International Standard for house-dust mite extracts. These results demonstrate that spent house-dust mite culture medium is an appropriate source of allergens from these organisms, and because of its low commercial value, may be an economical alternative for the production of allergenic extracts.

Allergens↗
PubMed2004

Identification and biosynthesis of an aggregation pheromone of the storage mite Chortoglyphus arcuatus.

In an effort to identify new pheromones from mites, the headspace of undisturbed colonies of the storage mite Chortoglyphus arcuatus was analyzed by GC-MS by use of a closed-loop stripping apparatus (CLSA) or solid-phase microextraction (SPME). The major compound emitted from the mites is (4R,6R,8R)-4,6,8-trimethyldecan-2-one (4R,6R,8R-8). The structure was elucidated by analysis of the mass spectrum, synthesis of authentic samples, and gas chromatography on a chiral phase. Bioassays show that this compound, for which we propose the trivial name chortolure, is an aggregation pheromone for both sexes of this species. Several related compounds are released in smaller amounts by the mites. The alarm pheromones of these mites, neral and geranial, can only be found in total extracts of the mites, in which 8 occurs only in minute amounts. The method of sampling is therefore crucial for pheromone identification. Feeding experiments with deuterated propionate showed that chortolure is a polyketide, formed by successive addition of four propionate units to an acetate starter.

Acaridae↗
PubMed1999

Is infestation the result of adaptive choice behaviour by the parasite? A study of mites and midges.

We studied the possibility that a parasite, a hydracharinid mite, chooses its host, a chironomid midge. Mites, Unionicola ypsilophora, were placed into containers with either one or two Chironomus plumosus pupae and we counted the number of mites on the midges after the latter had emerged. Fewer mites were rejected by hosts when they had a choice of host, suggesting that they actively choose which individual to parasitize. In several midge species collected in the wild, fluctuating asymmetry in wing length was a good predictor of mite infestation. We suggest that mites use some correlate of fluctuating asymmetry to make their choice of host. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1997

Birefringent Crystals and Abdominal Discoloration in the Predatory Mite Phytoseiulus persimilis (Acari: Phytoseiidae)

In response to grower complaints of poor performance of Phytoseiulus persimilis, mites from 14 commercial insectaries and research colonies were examined for pathogens. Some were found to have abdominal discolorations, manifested initially as two white stripes along the dorsal sides of the body within the Malpighian tubules. Advanced signs appeared as a large, centrally located, white spot or U-shaped discoloration in the distal opisthosoma within the rectum/anal atrium. White material often accumulated and hardened within the anus and formed a rectal plug that inhibited further excretion. Most affected mites were lethargic. Adults and immatures with abdominal discoloration contained numerous densely packed, birefringent, dumbbell-shaped entities. Though occasionally observed in the colon, they occurred most frequently within the Malpighian tubules and/or rectum and anal atrium. Dumbbells measured 2-4 &mgr;m long and contained prominent concentric rings. When observed by transmission electron microscopy, the entities lacked cellular organelles. Asymptomatic mites contained few or no such entities. Dumbbell-shaped inclusions were observed in P. persimilis from all sources examined. High levels of potassium, low levels of phosphorous and sulfur, and traces of chlorine were detected by energy-dispersive X-ray analysis. Guanine and uric acid, known nitrogenous wastes of arachnids, do not contain these elements. The chemical composition and structure indicate that the dumbbells are crystals. Both asymptomatic mites and those specimens exhibiting abdominal discoloration were examined for pathogens using light and transmission electron microscopy. Microsporidia, virus-like particles, and a rickettsia (genus Wolbachia) were observed in some mites but showed no correlation with white abdominal discoloration or associated crystal formation. Neither were pathogens always detected in symptomatic mites. Although birefringent crystals may be naturally occurring excretory products, the cause of white abdominal signs associated with crystal accumulation in P. persimilis is unknown. These signs indicate overall poor health.

Journal Article↗
PubMed2004

Lineage-specific tandem repeats riding on a transposable element of MITE in Xenopus evolution: a new mechanism for creating simple sequence repeats.

Xstir is a repetitive DNA sequence element that is extremely amplified as a common component of two different structures: a tandem repeat (Xstir array) and a MITE (miniature inverted-repeat transposable element) in the genome of Xenopus laevis. To elucidate the origin and evolutionary history of Xstir-related sequences, we investigated their species specificity among three Xenopus species (X. laevis, X. borealis, and X. tropicalis). Analyses by sequence alignment and digestion with restriction enzymes of genomic Xstir-related sequences revealed that the MITE (Xmix MITE) was well conserved among the three Xenopus species, with small lineage-specific differences. On the other hand, the tandem repeat element (tropXstir) in X. tropicalis was different from the Xstir that X. laevis and X. borealis have in common. Both sequences of Xstir and tropXstir were, however, different segments of the Xmix MITE. The results suggest that these tandem repeats were formed by partial tandem duplication of the MITE internal sequence in each lineage of X. tropicalis and of X. borealis/X. laevis after their branching. A molecular mechanism for creating and elongating the tandem repeats from the MITE is proposed.

Animals↗
PubMed2004

Crossreacting IgG antibodies against fox mite antigens in human scabies.

Scabies continues to be an important parasitic disease of mammals. There remain, however, major gaps in the understanding of the human host immune response, and a simple diagnostic test is lacking. In contrast to human mites, red fox mites (Sarcoptes scabiei var. vulpis) can be collected easily and have been used, due to crossreactivity, for enzyme-linked immunosorbent assay (ELISA) studies in dogs and pigs. We wanted to investigate the possibility that crossreactivity might also exist for the human mite, and determined titers against fox mite antigens by ELISA in 41 patients with scabies. Specific IgG was significantly higher in patients with scabies than in healthy controls (P=0.01). The sensitivity was, however, only 48%, although it increased slightly during treatment (P=0.86). A positive correlation was also noted between disease duration and severity of infestation (r=0.5), with specific IgG titers increasing in parallel with severity of symptoms (P=0.01). Patients with symptomatic scabies for more than 4 weeks had furthermore significantly higher IgG titers than patients with a shorter duration of disease (P=0.007). In conclusion, these findings demonstrate IgG antibodies in human scabies that crossreact with fox mite antigens, thus encouraging the search for improved ELISAs with more specific mite antigens to produce a more sensitive detection system for scabies in humans.

Aged↗
PubMed2006

Occupational sensitization to storage mites in the personnel of a water-damaged grocery store.

OBJECTIVES: To investigate the occupational exposure and sensitization to storage mites (SM) in sales staff working in a moisture-damaged and three healthy reference buildings. METHODS: The study population consisted of the entire personnel (n=12) in the moisture-damaged grocery store. They all suffered from persistent upper respiratory tract symptoms. Twelve (in results 11) symptom-free controls working in three healthy reference groceries were matched with age, sex and occupation. Dust samples from each building were examined for mites. The clinical study consisted of otorhinolaryngological examination and determination of IgE reactivity. Specific serum IgE antibodies were measured against three SMs and two house dust mites (HDM). Skin prick tests (SPT) were made to the same five mites and to five common aeroallergens. If sensitization to any of the SMs was detected, a nasal provocation test (NPT) was performed. RESULTS: SMs were found in all buildings. In all, seven cases and four control subjects showed IgE-mediated reactivity. Sensitization to mites was detected in six cases and in three controls and in 2/12 and 3/11 this was the only IgE antibody response observed. In addition, one case and one control subject were sensitized to common aeroallergens. NPT with SMs was positive in four cases and in one control. CONCLUSIONS: In grocery stores, the personnel are exposed to SMs. The risk of sensitization to mites is obvious and an IgE response can occur without any reactivity to common aeroallergens. SM allergy may in some cases explain the chronic rhinitis related to moisture-damaged buildings.

Animals↗