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PubMedDate not supplied

Cutaneous sensitivity to six mite species in asthmatic patients from five Latin American countries.

The prevalence of positive skin prick tests to the mite species Dermatophagoides pteronyssinus, D. farinae, Blomia tropicalis, Chortoglyphus arcuatus, Lepidoglyphus destructor and Aleuroglyphus ovatus was determined in 297 asthmatic adults and children living in seven cities of five Latin American countries. A standardized protocol and a common battery of extracts were used at each site. The mean wheal diameters were measured after 15 min, and those > or = 3 mm were considered positive. Sensitization to D. pteronyssinus varied from 60.7% in Cartagena to 91.2% in São Paulo; to D. farinae from 53.3% in Córdoba to 97.2% in Caracas; to A. ovatus from 26.6% in Bogotá to 71.2% in São Paulo; to B. tropicalis from 46.5% in Mexico City to 93.7% in São Paulo; to C. arcuatus from 33.3% in Mexico City to 75% in São Paulo; and to L. destructor from 30% in Mexico City to 76.2% in São Paulo. This study reported the results of skin test sensitivities in both children and adults. The studies from São Paulo and Córdoba were confined to children and thus could be compared; there was a significantly higher prevalence of cutaneous sensitivity to mite allergens in the children of São Paulo than in those of Córdoba (p < 0.001 for all mite species). Cutaneous sensitivity to mite allergens is very common in young and adult asthmatics in Latin America, in areas both at sea level and at high altitudes. Environmental control measures should be reinforced in the treatment of asthmatics in Latin America.

Adolescent↗
PubMedDate not supplied

Acarosan and the Acarex test in the control of house dust mite allergens in the home.

House dust mites are believed to be major triggers for allergic disease in atopic individuals. As part of a programme controlling dietary and aero-allergen exposure in high-risk infants, an acaricidal foam and powder (Acarosan) was applied to bedroom and main living room carpets, as well as upholstered furniture, on four occasions in the first year of life. Dust was assayed for mite antigen (Der p1) and these results compared with the semi-quantitative assay of guanine content (Acarex Test). After nine months mean Der p1 levels had decreased by 70% in the treatment group. Proportionally, the greatest fall occurred in those items that had the highest initial mite antigen content. The Acarex score does show a correlation with Der p1 levels, but cannot replace antigen assay when accurate data is required. A chemical acaricide may help reduce house dust mite antigen levels, but is not by itself sufficient to reduce levels below that considered critical for sensitisation.

Allergens↗
PubMed1995

Present state of research on house dust mites (Pyroglyphidae) in the Czech Republic.

Systematic research on house dust mites in the Czech Republic started in the early seventies, when mite fauna of human dwellings and distribution of pyroglyphid mites were studied. Special attention was paid to old-age-pensioners' homes and children's sanatoria. Pyroglyphidae were found also in the city air and in the dust of city pavements, especially in localities with high occurrence of domestic pigeons. While D. pteronyssinus and D. farinae mostly occurred in permanently inhabited flats, Euroglyphus maynei prevailed in recreation houses and some hospitals. Autumn increase of population density occurred in both, D. pteronyssinus and D. farinae populations, however, the number of protonymphs was remarkable higher than that of other developmental stage in D. farinae population. Special rearing technique was developed for the mass-culture of mites and a Czechoslovak patent was assigned to the technology of allergen preparation for the diagnostics and the desensibilization of patients with house-dust allergies.

Aged↗
PubMed1995

[Allergy to house dust mites].

There are presented the etiology and pathogenesis of house dust and house dust mite allergy. The house dust mite ecology, physicochemic and immunochemic properties of house dust mite allergens, methods of quantitating exposure to these allergens; the relationship between level of exposure, sensitization and disease, likewise avoidense measures for mite allergens in houses are described.

Allergens↗
PubMedDate not supplied

[Housedust mites++ in the city of Valdivia, Chile].

In the house dust there are different species of mites, which have medical importance because they are related to allergic asthma, rhinitis and/or dermatitis. Between april-august 1989 and march-june 1990, 100 samples of house dust collected in the city of Valdivia, Chile were analyzed. By using special techniques the samples were examined and classified. In the present research 70 samples of dust were positive, which showed one or more species of mites. Thirteen species and one genus were classified. The average quantity of house dust examined by sample was 0.69 g and a total of 701 mites were isolated, being identified 691 of them: Glycyphagus destructor (23.4%), G. domesticus (22.7%), Blomia tjibodas (19.2%), Cheyletus eruditus (6.5%) and Chortoglyphus arcuatus (12.0%), were the most frequent species found. In 74.2% of the positive samples two or more species of mites were observed, being the most common the association of two species, with the combinations: G. destructor-G. domesticus; G. domesticus-Tyrophagus putrescentiae; G. destructor-Ch. eruditus.

Animals↗
PubMedDate not supplied

Application of random amplified polymorphic DNA (RAPD) assay to the study of mites related to allergic diseases.

In this study, the conditions for the successful application of the random amplified polymorphic DNA (RAPD) assay to differentiate mite populations based on genetic variation were defined. Five species of mites related to allergic diseases were studied: Dermatophagoides pteronyssinus, D. farinae (2 strains), Blomia tropical is, Glycyphagus domesticus and Tyrophagus putrescentiae. The mites were isolated from pure cultures and processed according to the method described in this paper. The banding patterns obtained were different for all the species studied. When the DNA from two different strains of D. farinae were studied, the "fingerprint" banding patterns obtained showed differences between them. The random amplified polymorphic DNA assay may be a useful tool to aid the taxonomic study of mite populations.

Animals↗
PubMed1996

Distribution and density of house dust mites Dermatophagoides spp. (Acarina:Pyroglypidae) in the mattresses of two areas of Rome, Italy.

The distribution of Dermatophagoides farinae and D. pteronyssinus in two groups of houses in Rome was investigated by means of weekly sampling of dust on mattresses during the period of high mite density (May-July, 1994). All mattresses were infested; overall 4,179 live and dead mites were collected. In the two examined areas, a difference in species distribution was observed. D farinae was always the prevalent species, it was 94.7% in area A and 64.1% in area B; only in houses 9 and 10 D. pteronyssinus was the most abundant species (71.4% and 45.8%). Housekeeping practices were investigated by interviewing the tenants and relative humidily and indoor/outdoor temperature were measured during each weekly sampling. A correlation analysis revealed a significant relationship between housekeeping practices and mite density (r = 0.83). The poorest housekeeping practices produced the heaviest mite infestation, while good ones were associated with low densities.

Animals↗
PubMed1997

[Close positive correlation between the level of mite-specific lymphocyte proliferation and the percentage of peripheral blood eosinophils in infants with atopic dermatitis].

Eosinophils (Eo) are known to play a critical role in the chronic allergic inflammation, featuring pathologically in atopic dermatitis (AD), and the Eo percentage in the peripheral blood is elevated in AD infants (0 y) as well as in older AD children (3-15 y). In search of the most important factor in the increase of Eo percentage, we analyse the correlation between the level of Eo percentage in the peripheral blood and the levels of various allergy-related parameters. In AD infants, the level of Eo percentage was found to be correlated most strongly with the level of mite-specific lymphocyte proliferation expressed by S.I.F. (stimulation index measured by flow cytometry) (r = 0.88, p < 0.001). It also correlated significantly with the levels of serum IgE (r = 0.56, p < 0.05), egg white-specific IgE-RAST (r = 0.64, p < 0.01) and egg white-specific S.I.F.(r = 0.59, p < 0.02), but not with the levels of mite-specific IgE-RAST or candida-specific S.I.F. On the contrary, the level of Eo percentage correlated most intimately with the levels of serum IgE (r = 0.73, p < 0.001) and mite-specific IgE-RAST (r = 0.71, p < 0.001) in older AD children. These results suggest that mite-specific peripheral blood helper T lymphocytes, the proliferation of which is thought to be represented by S.I.F., play a more essential role in AD infants than in older AD children in the increase of Eo percentage in the peripheral blood.

Adolescent↗
PubMedDate not supplied

Cetirizine reduces conjunctival nonspecific hyperreactivity in children with mite allergy.

As mite allergy is characterized by a continuous allergen exposure, persistent inflammation is always detectable even during symptomless periods. It has been reported that mite allergic patients present a nonspecific hyperreactivity to different stimuli, including hyperosmolar solution. Since it has been reported previously that cetirizine is able to reduce minimal persistent inflammation due to mite allergy, the aim of the study was to investigate the effect of cetirizine on nonspecific conjunctival hyperreactivity. Twenty children with mite allergy were studied; two hyperosmolar conjunctival challenges were performed before and after cetirizine or placebo treatment, lasting one week. Patients treated with cetirizine showed a significant reduction in nonspecific conjunctival hyperreactivity compared to the placebo group (p < 0.05). In conclusion, cetirizine was able to reduce nonspecific hyperreactivity related to allergic inflammation.

Animals↗
PubMed1998

Dust mite proteolytic allergens induce cytokine release from cultured airway epithelium.

Endogenous proteolytic enzymes have been shown to be potential sources of airway inflammation inducing proinflammatory cytokine release from respiratory epithelial cells; however, whether any of the exogenous proteases from important allergen sources such as the house dust mite present in our environment behave in a similar fashion is unclear. To this end, we have investigated whether the mite cysteine and serine proteolytic allergens, Der p 1 and Der p 9, respectively, induced cytokine production from primary human bronchial epithelial cells and from the epithelial cell line BEAS-2B. Cells were exposed to mite proteases, and cells or supernatants were assayed for cytokine release, cytokine mRNA expression, and modulation of intracellular calcium ion concentration. Both proteases induced concentration- and time-dependent increases in the release of granulocyte-macrophage (GM)-CSF, IL-6, and IL-8 as well as an increase in the expression of IL-6 mRNA. Cytokine release and mRNA expression were first observed at 8 h and 2 h after protease exposure, respectively. The minimum concentration of each protease that was required to stimulate GM-CSF, IL-6, and IL-8 release was approximately 10 ng/ml. Cytokine release was initiated by 1 to 2 h of protease exposure, although maximum concentrations were detected only after a 24-h incubation. IL-6, but not IL-8 and GM-CSF, was shown to be degraded by both proteases at concentrations of > 2 microg/ml. The proteases also stimulated changes in the intracellular calcium ion concentration. All mite protease-induced phenomena were inhibited using appropriate protease inhibitors. These results suggest that the proteolytic activity of an allergen may stimulate the release of proinflammatory cytokines from human bronchial epithelium.

Allergens↗
PubMedDate not supplied

Influence of mite growth culture phases on the biological standardization of allergenic extracts.

House dust mites are a well known cause of asthma and other respiratory allergies. In order to improve the standardization of allergenic extracts for diagnosis and immunotherapy, it is important to determine the frequency and concentration of the components, both the major and the minor allergens during the growth period of the mite population. In a previous paper we demonstrated that the laboratory cultures of Dermatophagoides pteronyssinus and Dermatophogoides farinae exhibited three well differentiated growth phases: latency, exponential growth, and death of the culture. Biological standardization of extracts from the two mite species were carried out by skin prick tests in a group of 20 patients, using different concentrations of the extracts at the three growth phases. The patient sera were also studied by means of the RAST technique to determine the levels of specific IgE for each phase. The extracts produced from the exponential growth phase of the cultures revealed six times more relative allergenic activity in in vivo studies, and average RAST values were approximately three times higher than those extracts from latency and death phases. The reproducibility of the extract production method was assessed by comparing different batches obtained in similar conditions. The results showed batch-to-batch homogeneity allergenic activity. In conclusion, it was demonstrated that extracts obtained from cultures with the highest concentration of live mites (maximum growth phase) render the best diagnostic results in vivo and in vitro.

Adolescent↗
PubMed1976

A survey of fur mites in domestic rabbits.

A survey of six commercial rabbit colonies was conducted to determine the prevalence of the mite Cheyletiella parasitvorax. This mite was present in all six colonies, and 43.2% of 220 rabbits examined were infested. Listrophorus gibbus, reported only once previously in domestic rabbits in the United States, was found in four of the six colonies, and in 7.3% of the 220 rabbits examined. Non-parasitic mites were found in 3.2% of the samples. Over 50% of the rabbits examined had inapparent mite infestations.

Animals↗
PubMedDate not supplied

Extracts from various mite species contain cross-reactive and noncross-reactive IgE epitopes. A RAST inhibition study.

Previous studies have demonstrated the high incidence of Dermatophagoides, Euroglyphus, Blomia, Lepidoglyphus and Chortoglyphus spp. sensitizations in a mite-allergic population. The aim of this study was to evaluate immunological cross-reactivity among the above mentioned groups, using sera from a nonrural population allergic to mites, from a subtropical area (Canary Islands). RAST inhibition studies demonstrated significant cross-reactivity among Dermatophagoides and Euroglyphus species (> or = 65% of maximum theoretical inhibition), as also noted by other authors. Blomia kulagini demonstrated scarce cross-reactivity with Dermatophagoides, Lepidoglyphus and Chortoglyphus species (< or = 30% of maximum theoretical inhibition) and medium level with Euroglyphus maynei (45% of maximum theoretical inhibition). Chortoglyphus arquatus demonstrated high cross-reactivity levels with the other species studied. The results obtained in this study demonstrated the scarce immunological cross-reactivity between Pyroglyphidae and non-Pyroglyphidae mites, thus suggesting the polysensitization of the studied population to different mite species.

Adolescent↗
PubMed1998

House dust mite allergen accumulation on sheepskins.

AIM: Sheepskins, which are often used as infant bedding in New Zealand, are known to harbour large quantities of house dust mites and their allergens. In this study we determined the rate of accumulation of the house dust mite allergen, Der p 1 on new sheepskins, and the effects of washing and dry cleaning on its removal. METHODS: New sheepskins were placed on living-room floors (n = 6) and mattresses (n = 6) in six domestic dwellings in Wellington. Sheepskin dust samples were collected by vacuuming before placement, and at two, four and six weeks, after which they were warm-washed. They were replaced for a further six weeks, then dry-cleaned. Dust samples were collected before and after washing and dry-cleaning, and from mattresses and living-room floors. Dust samples were analysed for Der p 1 by double monoclonal antibody ELISA. RESULTS: Der p 1 levels rapidly increased in sheepskins placed on living-room floors and mattresses to a geometric mean level (range) of 9.0 micrograms/g (1.1-102.2) and 29.4 micrograms/g (5.3-131.1) at six weeks, respectively. After warm-water washing and replacement for a further six weeks, these levels were higher at 75.5 micrograms/g (50.1-260.4) and 31.9 micrograms/g (11.1-75.2), respectively. Sheepskin Der p 1 accumulation correlated with mattress (r = 0.78), and living-room floor Der p 1 levels (r = 0.94). Warm water washing and dry-cleaning reduced sheepskins Der p 1 levels by a mean of 79.2% and 95.3%, respectively. CONCLUSIONS: Sheepskins rapidly accumulate house dust mite allergens from the domestic environment. Due to very high levels and rapid accumulation of Der p 1, sheepskins as infant bedding should be discouraged for infants at risk of sensitisation to house dust mites. If they are to be used then it is important that they are washed or dry-cleaned regularly.

Allergens↗
PubMed2005

Molecular identification of pathogenic house dust mites using 12S rRNA sequences.

House dust mites are microarthropods implicated in the cause of allergic diseases. Currently, there is no phylogenetic analysis of dust mites based on genomic or mitochondrial DNA (mtDNA) evidence. For the first time, we report evolutionary relationships based on partial mtDNA 12S rRNA sequences among the four dust mite families Pyroglyphidae (Dermatophagoides pteronyssinus), Glycyphagoidea (Glycyphagus privatus), Acaridae (Aleuroglyphus ovatus), and Echimyopodidae (Blomia tropicalis). Thirteen sequence variants were obtained and phylogenetic analysis showed two monophyletic clades composed of two species each. Contrary to current taxonomic classification, the Acaridae clustered in a monophyletic group with the Pyroglyphidae. Considering the current difficulties in identifying these medically important species for the purpose of eradication and treatment, it is significant that sequence data are capable of discriminating between species belonging to different families of dust mites.

Acaridae↗
PubMed2003

Genetic variations of AA genome Oryza species measured by MITE-AFLP.

MITEs (miniature inverted-repeat transposable elements) are the major transposable elements in Oryza species. We have applied the MITE-AFLP technique to study the genetic variation and species relationship in the AA-genome Oryza species. High polymorphism was detected within and between species. The genetic variation in the cultivated species, Oryza sativa and Oryza glaberrima, was comparatively lower than in their ancestral wild species. In comparison between geographical lineages of the AA genome species, African taxa, O. glaberrima and Oryza barthii, showed lower variation than the Asian taxa, O. sativa, Oryza rufipogon, and Oryza nivara, and Australian taxon Oryza meridionalis. However, another African taxon, Oryza longistaminata, showed high genetic variation. Species relationships were analyzed by the pattern of presence or absence of homologous fragments, because nucleotide sequences of the detected MITE-AFLP fragments revealed that the same fragments in different species shared very high sequence homology. The clustering pattern of the AA-genome species matched well with the geographical origins (Asian, African and Australian), and with the Australian taxon being distant to the others. Therefore, this study demonstrated that the MITE-AFLP technique is amenable for studying the genetic variation and species relationship in rice.

Cluster Analysis↗
PubMed2003

Death in anaphylaxis in a man with house dust mite allergy.

Up to recently the post-mortem diagnosis of anaphylaxis has been based solely on circumstantial evidence. With the development of assays for mast cell tryptase it is now possible to verify cases of suspected anaphylaxis. Here we present one such case, which initially appeared to be due to sudden death of unknown cause. A 47-year-old farmer was found dead in his bathroom around midnight. Hospital records revealed that he had previously been diagnosed with an allergy to house dust mites. He had also had infrequent episodes of airway symptoms, nausea, hypotension and diarrhoea usually after going to bed. The forensic autopsy did not give any clue to the cause of death. Serum tryptase in post-mortem blood was found to be substantially elevated in two samples (170 and >200 microg/L). Analysis of allergen-specific IgE showed high values for Dermatophagoides pteronyssinus and farinae. High mite allergen levels were found in dust obtained from the patient's mattress. The results of the immunological tests support the assumption that he died of anaphylactic shock. The circumstances and the patient's history of previous attacks after going to bed point to the fact that exposure to mite contaminated food and/or exposure to mite allergens in bed might have caused his death.

Adult↗
PubMed2005

A candidate autonomous version of the wheat MITE Hikkoshi is present in the rice genome.

A miniature inverted-repeat transposable element (MITE), designated as Hikkoshi, was previously identified in the null Wx-A1 allele of Turkish bread wheat lines. This MITE is 165 bp in size and has 12-bp terminal inverted repeats (TIRs) flanked by 8-bp target site duplications (TSDs). Southern and PCR analyses demonstrated the presence of multiple copies of Hikkoshi in the wheat genome. Database searches indicated that Hikkoshi MITEs are also present in barley, rice and maize. A 3.4-kb element that has Hikkoshi-like TIRs flanked by 8-bp TSDs has now been identified in the rice genome. This element shows high similarity to the 5' subterminal region of the wheat Hikkoshi MITE and contains a transposase (TPase) coding region. The TPase has two conserved domains, ZnF_TTF and hATC, and its amino acid sequence shows a high degree of homology to TPases encoded by Tip100 transposable elements belonging to the hAT superfamily. We designated the 3.4-kb element as OsHikkoshi. Several wheat clones deposited in EST databases showed sequence similarity to the TPase ORF of OsHikkoshi. The sequence information from the TPase of OsHikkoshi will thus be useful in isolating the autonomous element of the Hikkoshi system from wheat.

Alleles↗