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PubMed2006

House dust mite species and allergen levels in Galicia, Spain: a cross-sectional, multicenter, comparative study.

BACKGROUND AND OBJECTIVES: Mites are important sources of allergens in Galicia, Spain. The objective of this study were to identify the main mite species and to determine allergen levels in mattresses from different locations in Galicia. MATERIAL AND METHODS: Dust samples were collected with a portable vacuum cleaner for 2 minutes from 2 m2 of the surface of the mattress used by mite allergic patients and controls. After collection, samples were immediatel frozen. Mite species were collected, identified, and counted, and the results expressed as mites per gram of dust. Mite allergen levels (Der p 1 and Der f 1) were measured using monoclonal antibodies. All individuals answered a questionnaire about the characteristics of their homes. RESULTS: A total of 332 dust samples were collected (112 from mite allergic patients and 220 from controls). Thirty-two species were identified. The mean age +/-SD of all the participants was 32.4 +/- 20.8 years and of the mattresses 7.6 +/- 5.9 years. The geometric mean of the total mite counts was 910.2 mites per gram (896.2 mites per gram in the mattresses of mite allergic patients and 917.3 in the mattresses of control subjects; P > .05). The main species was Dermatophagoides pteronyssinus, which was present in 97.6% of the samples (geometric mean, 584.7 mites per gram). The geometric mean level of Der p 1 was 13.1 microg/g of dust: 11.9 in the mattresses of mite allergic patients and 13.8 in the mattresses of control subjects. The geometric mean level of Der f1 was 1.1 microg/g: 1.5 in the mattresses of mite allergic patients and 0.8 in the mattresses of control subjects. Environmental risk factors associated with high mite counts included obvious signs of humidity in the bedroom and the age of the mattress. CONCLUSIONS: The mite fauna in Galicia is comprised of many species, several of which are known to be of allergologic importance. The total population is exposed to very high levels of mite allergens.

Adolescent↗
PubMed2002

Spider-mite allergy and asthma in fruit growers.

Asthma and allergic diseases caused by domestic mites such as house dust mites and storage mites are major health problems worldwide. In contrast to domestic mites, spider mites are outdoor phytophagous mites causing significant damage to fruit leaves throughout the world. After several case reports of spider mite-induced asthma and allergy, cross-sectional surveys have demonstrated that spider mites are important allergens in the development of asthma and rhinitis in fruit farmers. Interestingly, epidemiological surveys have also demonstrated that spider mites are common sensitizing allergens that are related to the prevalence of asthma and rhinitis, even in the non-farming population exposed to spider mites. Protein analysis has demonstrated that crude extracts derived from spider mites contain several major allergens, and that N-terminal amino acid sequencing of the major allergens is not homologous with any previously characterized domestic mite allergens, suggesting that major allergens derived from spider mites are unique in terms of cross-reactivity to domestic mites. Taken together, these findings suggest that spider mites are important allergens in the development of asthma among the exposed non-farming population as well as among fruit farmers themselves, and that allergens derived from spider mites may be novel allergens.

Adolescent↗
PubMed1992

Exposure to house dust mites in homes of people with atopic dermatitis.

The median relative density of house dust mite populations was determined in mattresses in the homes of 23 people with atopic dermatitis (AD) who were mite-sensitive. It was significantly higher (total mites [dead and live] 174/0.1 g of dust: live mites 45.5/0.1 g) than in those of 23 healthy non-atopics (total mites 52/0.1 g; live mites 7.5/0.1 g; P < 0.05, < 0.01, respectively; Mann-Whitney U-test). There was no significant difference between mite population densities in mattresses in damp homes (n = 27; total mites 188/0.1 g; live mites 36/0.1 g) and those in homes with no damp (n = 19; total mites 116/0.1 g; live mites 26/0.1 g). These data demonstrate a clear association between AD and exposure to large numbers of mites, independent of the presence of domestic damp. People with AD were exposed to densities of > 500 mites/0.1 g of mattress dust five times more frequently than non-atopics, corresponding to a relative risk of 25.0, but were exposed to densities of < or = 50 mites/0.1 g five times less frequently. The overall relative risk for AD, with a cutoff of 50 mites (total)/0.1 g, was 8.1. There was an obvious positive correlation between magnitude of exposure and frequency of disease. It is hypothesized that the association between high densities of mites and AD is related to differences in lipid composition of the shed squames on which the mites feed: those of people with AD may be of greater nutritional value than those of non-atopics, thus enhancing mite population growth.

Adolescent↗
PubMed2006

Enzymatic activity in extracts of allergy-causing astigmatid mites.

Many of the previously characterized allergens of house dust mites are known to be proteases, and this enzymatic activity is thought to contribute to their allergenicity. Other astigmatid mites, including stored-product mites and the ectoparasitic itch mite, Sarcoptes scabiei De Geer, are also known to be allergenic, but little or nothing is known about their enzymatic activities. The purpose of this study was to characterize the enzymatic activities present in extracts of the parasitic itch mite and from eight other species of free-living astigmatid mites. Extracts were prepared from one parasitic mite (S. scabiei), five stored-product mites (Chortoglyphus arcuatus (Troupeau), Lepidoglyphus destructor (Schrank), Blomia tropicalis Bronswijk, Cock, Oshima, Tyrophagus putrescentiae (Schrank), and Acarus siro L.), and three house dust mites [Dermatophagoidesfarinae Hughes, Dermatophagoides pteronyssinus (Troussart), and Euroglyphus maynei (Cooreman) ]. ApiZym strips were used to screen for the presence of 19 individual enzyme activities. Digestion of nine other substrates was evaluated by spectrophotometric or electrophoretic methods. All mite extracts exhibited some form of phosphatase, esterase, aminopeptidase, and glycosidase activity, although their substrate specificities varied considerably. Itch mite extract did not possess detectable serine peptidase activity nor was it able to hydrolyze gelatin or casein, whereas all other mite extracts exhibited these activities. Storage mite extracts possessed enzymes capable of degrading the widest range of substrates, whereas itch mite extract had the most limited proteolytic capacity. Extracts of nine species of allergy-causing astigmatid mites contain wide and diverse repertoires of enzymatic activities. These catalytic activities may be important contributors to the induction and manifestation of inflammatory and immune responses to mites in patients.

Animals↗
PubMedDate not supplied

[Recent experience with mites in stored products].

The A.A. refer a recent experience about the isolation and identification of same species of storaged timber mites. They believe that these mites are responsible of dermatitis at the trunk and the arms of timber workers. Mites are the most elderly living species on the earth, they can live and grow in different environments, such as plants, flowers, animals, men, earth, lake and sea waters, organical rubles, houses, mattresses, old books etc. There are free-living, saprophitic, parasitic and predator mites. Generally, primary mites live either freely or as commensals feeding on conserved foodstuff and on what they find available. Secondary mites, i.e. parasites and predators, live off primary mites and insects infesting foodstuff. Direct damage to foodstuff are not to be considered important, whereas indirect damages are more serious, due to the contamination of bodies and stools of mites that are rich in nitrogen. Some secondary mites may attack foodstuff workers causing characteristic dermatitis: they can act either directly, by sting and bites, or indirectly, provoking on allergic hypersensitivity. In this study the A.A. used the floating method to isolate timber mites, and then, these have been photographed at the microscope to obtain an easier and more complete identification. The A.A. describe a heterogeneous fauna consisting of both adult and larval-status insects, some species of free-living mites (Oribatula Tibialis) and, in particular, of two species secondary mites, predator, belonging to the Prostigmata sub-order. The Cheyletus Eruditus (Cheylatidae family) is a whitish mite feeding mostly on insect larva and primary mites living in foodstuff. When no prey is available, the Cheyletus Eruditus eats individuals of its own species. The Pyemotes Herfsi (Pyemotidae family) is a little white mite feeding on insect larva. It lives in conserved foodstuff and may attack man causing characteristic dermatitis such as those described by the A.A. The A.A. conclude dealing with the possible preventive and therapeutic measures tend to keep phisic-chemicals parameters of foodstuff and others conserved products afar from the values suitable for the growth of parasites (water content min. 13%, environmental humidity min. 60-65%, appropriate temperature etc.). Therapeutic procedure are based either on physical media: infra-red rays, gamma-rays, electric fields for the transformation of temperature or using chemical mixtures containing methyl bromide, carbon tetrachloride and hydrogen sulphide. Among the therapeutic procedures, however, the biological pest control using chemical media associated with antagonist mites of the infesting species is to be preferred.

Animals↗
PubMed1999

Abundance of house dust mites in relation to climate in contrasting agricultural settlements in Israel.

The correlation between climatic conditions and mite numbers in houses from rural areas was studied in 13 agricultural communities (kibbutzim and moshavim) in nine geo-climatic subregions of Israel. Mites were present in 97% of the dust samples. The average number of mites per gram of dust in the different localities ranged between 84 and 2053. The maximum number of mites (7440/g dust) was found in a carpet from a house in Geva Carmel in the northern coastal region. The most prevalent species of mites were Dermatophagoides pteronyssinus and Dermatophagoides farinae, which were found in 85.6% and 71.3% of the samples, respectively. The house dust mites D. pteronyssinus, D. farinae and Euroglyphus maynei constituted 94.8% of the mites. Most of the mites were isolated from the carpets and sofas (37.0% and 33.7%, respectively), and a smaller number from beds (29.3%). The smallest number of mites (< or = 250/g dust) were found at a minimum relative humidity (RH) of 30% and lower, with a maximum temperature of 32 degrees C and higher, i.e. in the Jordan valley and Negev mountains. A greater number of mites (250-500/g dust) were found at a minimum ambient RH of 35-40% and a maximum temperature of 32 degrees C and higher, i.e. the Hula valley. A large number of mites (500-1000/g dust) were found at a minimum RH of 35-40% with a maximum temperature of 30 degrees C and lower, i.e. in the Judean and Samarian range, as well as in upper Galilee. The largest number of mites (1000-2000/g dust) was found at a minimum RH of 45% and higher, with a maximum temperature ranging between 30 and 32 degrees C. These conditions occur in the coastal strip, the coastal plain and in the Judean and Samarian foothills. A monthly examination of two houses in Zova, a kibbutz in the Judean hills next to Jerusalem, and two houses from Palmachim, a kibbutz in the coastal region, revealed that the highest prevalence of mites was found in the months April-November and May-November, respectively. In Zova, the highest number of mites were found during the months of June and July while the highest concentrations of D. pteronyssinus-antigen (Der p I) were measured during the month of September. A positive correlation between mite numbers and the quantity of Der p I in house dust was found.

Agriculture↗
PubMed1990

Allergy to storage mites in asthmatic patients and its relation to damp housing conditions.

The relation between allergy to house dust mites and allergy to storage mites was studied in 326 patients with bronchial asthma. A positive RAST to house dust mites was found in 24.5% and to storage mites in 7.4%. There was a close association between a positive RAST to house dust mites and a positive RAST to storage mites, and 91.6% had a positive RAST to both. Only 0.9% with a negative RAST to house dust mites had a positive RAST to storage mites, whereas the frequency was 27.5% in those with a positive RAST to house dust mites. Present occupation with exposure to storage mites was found in 20.8% with a positive RAST to storage mites. A positive RAST to both house dust mites and storage mites was significantly associated with anamnestic indicators of damp housing conditions. The close association between allergy to house dust mites and allergy to storage mites in this study is probably caused by a common environmental factor, i.e. damp housing conditions.

Agricultural Workers' Diseases↗
PubMed1989

The study of house dust mites in Taiwan.

By using a radioallergosorbent test (RAST) and intradermal skin testing, our previous studies strongly suggested that house dust mites are the most important allergen in Taiwan, especially in asthmatic children. This study was conducted to determine the distribution of house dust mites in houses of mite-sensitive asthmatic children and normals, the species of mites in various house dust samples, the seasonal prevalence, and the relation between the content of mite allergen and the mite density in dusts. Serial samples were collected every month between February 1986 and January 1987 from 61 houses of mite-allergic patients and nine normals. About 1 m2 surface area each of (A) family couch, (B) TV room floor carpet, (C) mattress, and (D) bed room floor carpet was vacuumed for one minute. The flotation method was used to collect mites in dusts and mites were counted under an inverted phase contrast microscope. Identification of house dust mite species was also performed. The RAST inhibition method was used for assay of mite allergen in dust extracts. The results showed the following six points. (1) Dermatophagoides pteronyssinus (DP) was the dominant species found in house dust in the Taipei area (78.8%). (2) The mean number of mites was greater in August through November and lowest in July. (3) The content of mite allergen did not correlate with the number of mites in dust sample. (4) The average number of mites in patients' houses was not different from that in normals' houses.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1995

House dust mite fauna in Thailand.

House dust mites have been shown to be the most important source of allergen in Thailand. The results of our initial mite survey were in conflict with previous data reported 20 years ago. To evaluate the current condition of mite fauna in Thailand, we conducted a larger scale survey of house dust mites in dusts from three different parts of the country. A total of 630 mattress dust samples was collected from various types of housing from central, northern and northeastern parts of Thailand. House dust mites were identified and enumerated by standard techniques and 388 dust samples were analysed further for group I antigen by a two-site monoclonal antibody enzyme-linked immunosorbent assay. House dust mites were identified in 555/630 (88.1%) of dust samples collected; 27.6% of these 555 samples contained over 100 mites per gram of fine dust. Dermatophagoides pteronyssinus was the most abundant species found with a mean count of 87.2 mites per gram of dust (range 1-1460). Group I antigen was detected in 380/388 (97.9%) samples analysed and 330 of which (86.8%) contained over 2 micrograms/gm of group I antigen. The highest density of mites was found in dusts from northern Thailand whereas dusts with highest amount of antigen were those collected from the northeastern part. Some degree of correlation between mite count and mite allergen was observed (r2 = 0.133, P < 0.001). No significant difference in the mite count and mite allergen was found among various types of housings. House dust mites are the source of allergens ubiquitously found all over Thailand.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed2001

Host plant-induced changes in detoxification enzymes and susceptibility to pesticides in the twospotted spider mite (Acari: Tetranychidae).

Adult female twospotted spider mites, Tetranychus urticae Koch, reared on lima bean plants were moved to cucumber, maize, or new lima bean plants (the latter being a control) and evaluated after 24 h or 7 d for changes in susceptibility to three pesticides and in levels of related detoxification enzymes. The largest and most consistent changes were observed in mites feeding on cucumber. Susceptibility of mites on cucumber to the synthetic pyrethroids bifenthrin and lambda-cyhalothrin was greater than that of mites reared on lima bean and maize after only 24 h on the plants, and remained higher after 7 d. Mites on cucumber also were more susceptible to the organophosphate dimethoate than were mites on lima bean, but only after 7 d on the host. Susceptibility was inversely related to activities of both general esterase and glutathione S-transferase (GST) in mites on cucumber; general esterase and GST activities were 60 and 25% lower, respectively, than activities of twospotted spider mite on lima bean after 7 d of feeding. Mites on maize were slightly but significantly more susceptible than those on lima bean to bifenthrin, but not to lambda-cyhalothrin, after 7 d and to dimethoate after 24 h but not after 7 d. General esterase and GST activities in twospotted spider mite fed on maize for 24 h were 20 and 16% higher, respectively, than activities in twospotted spider mite on lima bean, but general esterase activity was 30% lower than lima bean-fed mites and GST was not different after 7 d. Thus, plant-induced changes in general esterase activity, perhaps in combination with GST activity, in twospotted spider mite appear to be inversely related to, and possibly responsible for, changes in susceptibility of twospotted spider mite to several pesticides, particularly the synthetic pyrethroids. General esterases appear to play less of a role in the detoxification of the organophosphate insecticide dimethoate.

Animals↗
PubMed2001

Citrus red mite (Panonychus citri) may be an important allergen in the development of asthma among exposed children.

BACKGROUND: Recent investigations have demonstrated that spider mites are important allergens in the development of asthma in fruit-cultivating farmers. OBJECTIVE: The aim of this study was to evaluate the sensitization rate to the citrus red mite (Panonychus citri) in children living in rural areas, and to determine the allergenic cross-reactivity with other mites. METHODS: A total of 7254 children (ages 7-15 years) living in rural areas were enrolled, and each subject was evaluated by a questionnaire and a skin prick test. Allergenic cross-reactivity was evaluated by ELISA inhibition tests. RESULTS: The most common sensitizing allergens were house dust mites, followed by citrus red mite and cockroach. High serum-specific IgE bindings to the citrus red mite were detected in 21 of 100 randomly selected subjects. The prevalence of asthma was higher among those with positive skin responses to the citrus red mite than with negative skin responses to this mite. ELISA inhibition tests showed that IgE bindings to this mite were minimally inhibited with additions of domestic mites. CONCLUSION: Spider mites such as the citrus red mite may be important outdoor allergens among children living in rural areas, and spider mite-derived allergens have unique allergenic determinants compared with domestic mites.

Adolescent↗
PubMed2004

Sequence tag catalogs of dust mite-expressed genomes: utility in allergen and acarologic studies.

Dust mites are a major source of indoor allergens. They contain a large number of components that react with immunoglobulin (Ig) E in individuals with allergies and are capable of inducing sensitization, and allergic respiratory and cutaneous diseases. With a significant proportion of the population affected in some way by mite allergies, it is essential that we improve our understanding of these organisms so that control strategies could be defined and its allergens better understood. Thus, we have initiated a project using the expressed sequence tagging (EST) strategy to study the major species of dust mites associated with allergic diseases, in particular, the American house dust mite, Dermatophagoides farinae, as well as Blomia tropicalis, the most prevalent mite in domestic tropical dwellings. The work has recently been expanded to include 'storage' mites such as Tyrophagus putrescentiae, Acarus siro, Lepidoglyphus destructor, Glycyphagus domesticus, Suidasia medanensis, and Aleuroglyphus ovatus. More than 50% of the initial 3000 ESTs from the D. farinae and B. tropicalis dust mites showed significant matches to known genes and were categorized into eight functional groups (such as proteins involved in metabolism, gene expression, protein synthesis, cell signaling, etc.). Of specific interest, however, were the homologs to known mite allergens, in addition to a number of sequences bearing significant homology to allergens from non-mite sources previously not known to exist in mites. The availability of these allergen sequences has facilitated their expression and subsequent characterization in our laboratory in terms of their IgE-binding reactivity. The wealth of sequence information, generated via the EST project, has also facilitated the identification of polymorphic forms of allergens, the investigation of differential gene expression under various environmental conditions via DNA microarrays, as well as the analysis of protein level expression profiling via the proteomics approach. Additionally, ESTs have also ameliorated the understanding of the phylogenetic relationships between mites, and enabled the isolation of gene products crucial for life processes so that mite control strategies can be more effectively devised. Taken together, the utilization of the EST strategy has opened up numerous new avenues by which the allergist can engage more effectively in the study of dust mites with the ultimate aim of developing appropriate treatment regimens for mite-induced allergy.

Animals↗
PubMed2005

House dust mites, our intimate associates.

House dust mites have lived in human contact from time immemorial. Human dander or dead skin constitutes the major organic component of the house dust ecosystem. Because the mites feed on dander, dust mites and human association will continue to co-exist as part of our environment. Efficient house-keeping practice is the best form of control to reduce infestation. However, special precautions are important when individuals are susceptible or sensitive to dust mites. House dust mites are responsible for causing asthma, rhinitis and contact dermatitis. The respiratory allergies are caused by the inhalation of dead or live mites, their faecal matter or other byproducts. Immune factors are of paramount importance in the development of dust related or mite induced respiratory diseases. House dust mites were found in some 1,000 samples of dust taken from approximately 330 dwellings in Peninsular Malaysia and Singapore. Mattresses, carpets, corners of a bedroom, and floor beneath the bed are favourable dust mite habitats. The incriminating species based on studies here and elsewhere, as well as many other species of dust mites of unknown etiological importance are widely distributed in Malaysian homes. Density of dust mites in Malaysia and Singapore is greater than in temperate countries. Prevention and control measures with reference to subjects sensitive to dust mite allergies, including chemical control described in studies conducted in Europe and America are discussed. However, a cost free and most practical way to remove mites, their faecal matter and other products is to resort to sunning the bedding and carpets to kill the living mites, and then beaten and brushed to remove the dust and other components.

Allergens↗
PubMed1999

Mesostigmatid mite infestations of rodents in diverse biotopes of central and southern India.

Examination of 165 rodents trapped in domestic, peridomestic, and feral biotopes of central and southern India revealed the presence of 1,359 mesostigmatid mites. Rodents in central India were infested with 1 species of mite, Laelaps nuttalli; 98% of these mites were recovered from the peridomestic rodent Bandicota bengalensis. Material from the burrow nest of a peridomestic rodent examined in central India revealed the mite, Hypoaspis miles. Rodents from the diverse biotopes of southern India were infested by 8 species of mites: L. nuttalli, Laelaps buxtoni, Laelaps myonyssognathus, Androlaelaps aduncus, Androlaelaps marshalli, Androlaelaps sp. A, Hypoaspis sp. 1, and Hypoaspis sp. 2. Sheep from nearby villages regularly graze in feral biotopes. From the hair of these sheep, 2 species of mesostigmatid mites were recovered, A. aduncus and A. marshalli. The sheep appeared to aid the dispersal of rodent-infesting mites passively. Laelaps nuttalli was the predominant mite species found on the peridomestic rodent B. bengalensis. In both central and southern India, the prevalence, mean intensity, and relative density of this mite were much higher on peridomestic rodents than on domestic and feral rodents. A significant negative correlation was found between the numbers of mites and fleas infesting rodents in central India. A highly significant positive association between A. marshalli and A. aduncus on the feral rodent Tatera indica was recorded. In southern India, the overall prevalence of the 8 species of mites was highest on Mus platythrix. However, the combined prevalence of these mites on 2 feral rodents T. indica and M. platythrix was lower than their prevalence on B. bengalensis. Similarly, the combined values for mean intensity and relative density of these mites on the 2 feral rodents were lower than on the peridomestic rodent B. bengalensis.

Animals↗
PubMed2001

House dust mite avoidance measures for perennial allergic rhinitis.

BACKGROUND: In developed countries, it is estimated that 15% of the general population suffer from one or more allergic disorders, of which allergic rhinitis is the most common. Perennial rhinitis is most often due to allergy to the house dust mite. In such patients, house dust mite avoidance is logical, but there is considerable uncertainty regarding the efficacy and effectiveness of interventions designed to reduce dust mite exposure. OBJECTIVES: To assess the benefit (and harm) of measures designed to reduce house dust mite exposure in the management of house dust mite sensitive allergic rhinitis. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, Central, MEDLINE and EMBASE. No restrictions on the language of publication were employed. The bibliography of each paper and other published reviews were checked for further references. We wrote to first authors of all included trials in an attempt to identify further published and unpublished trials. SELECTION CRITERIA: Randomised controlled trial (with or without blinding), in which house dust mite control measures have been evaluated in comparison with placebo or other dust mite avoidance measures, in patients with clinician diagnosed allergic rhinitis and confirmed allergy to dust mite. DATA COLLECTION AND ANALYSIS: Two reviewers independently checked titles and abstracts identified by the searches and full text copies of all papers of potential relevance were considered. Trials were graded for methodological quality using the Cochrane approach. Data extraction was performed in a standardised manner. Meta-analysis was neither possible, nor considered appropriate, because of the heterogeneity of the patient groups studied; a narrative overview of the results is therefore presented. MAIN RESULTS: Four trials satisfied the inclusion criteria, all of which were small and of poor quality. Two trials investigated the efficacy of acaricides, a third investigated the role of high-efficiency particulate air (HEPA) filters, whilst a fourth investigated the efficacy of a bedroom environmental control program that comprised use of a barrier mattress cover, fortnightly washing of bed covers, removal of soft furnishings and daily cleaning. Each of the four trials showed the interventions to result in significant reductions in house dust mite load when compared with control. Trial results suggest that the interventions may be effective in reducing some rhinitis symptoms, though it is not possible to provide a reliable summary estimate about the magnitude of such symptom reduction. No serious adverse effects were reported from the interventions. REVIEWER'S CONCLUSIONS: Trials to date have been small and of poor methodological quality making it difficult to offer any definitive recommendations on the role, if any, of house dust mite avoidance measures in the management of house dust mite sensitive perennial allergic rhinitis. The results of these studies suggest that interventions designed to reduce house dust mite exposure in patients with house dust mite allergic perennial rhinitis may be of some benefit in reducing rhinitis symptoms. Data at present is only available for acaricides, HEPA filters and a bedroom-based environmental control program; therefore, if considered appropriate, these should be the interventions of choice.

Animals↗
PubMed1999

Allergenicity of the mite Hemisarcoptes cooremani.

BACKGROUND: A researcher experienced allergic symptoms while working with the astigmatid mite Hemisarcoptes cooremani cultured on scale insects. This mite is a predator of scale insects that often parasitize many perennial vascular plants in orchards, gardens, and ornamental nurseries worldwide; therefore, orchard and ornamental nursery workers and gardeners may be exposed to this mite. OBJECTIVE: We investigated the possible allergenicity of H. cooremani and the cross-reactivity between it and other allergy-causing astigmatid mites. METHODS: Serum from a subject who experienced allergic symptoms while working with H. cooremani was analyzed for IgE and IgG to proteins in an extract of this mite and of other astigmatid mites known to cause allergic reactions. The serum was used to probe proteins fractionated by SDS-PAGE or precipitated by CIE using rabbit antiserum. In addition, the subject's serum was used to directly precipitate proteins in extracts of H. cooremani and other mite species. RESULTS: SDS-PAGE and immunoblotting of proteins in an H. cooremani extract showed the reference serum contained IgE directed at 16-kD and 19-kD proteins. Crossed radioimmunoelectrophoresis reaction showed that the subject's serum contained antibody that precipitated a protein in an H. cooremani extract and that IgE bound to this protein. The proteins in an extract of H. cooremani did not precipitate when reacted with rabbit antisera against the dust mites D. farinae, D. pteronyssinus, and E. maynei, or the storage mites B. tropicalis, L. destructor, and T. putrescentiae. This indicated there was no cross-reactivity between H. cooremani and these mites. CONCLUSION: These results indicated that an extract of the mite H. cooremani contained at least two prominent IgE binding proteins that were not present in the other astigmatid mites. Thus, H. cooremani is the source of unique allergenic proteins and allergy to this mite may develop in orchard and ornamental nursery workers and gardeners.

Allergens↗
PubMed2004

Red, distasteful water mites: did fish make them that way?

Water mites (Acari: Hydrachnida) are unusual among the typically cryptic freshwater fauna in that many species are brightly colored red or orange, and also appear to be distasteful to fish. This apparent aposematism (use of color to warn predators) has been previously explained as the evolutionary end-product of pressure from fish predation. The fish-predation argument has been supported by observations that fish spit out red mites, powder made from red water mites is more distasteful to fish than powder made from non-red mites, and red mites appear to be more abundant than non-red mites in water bodies where fish are present. In this paper, we challenge the hypothesis that fish were the sole driving force behind the evolution of aposematism in water mites. We show that non-red mites actually dominate in water bodies with fish, and that red mites are more abundant in temporary, fishless water bodies. We also demonstrate that powder made from red, terrestrial velvet mites (Trombidiidae) was as distasteful to fish as powder made from red water mites. We suggest that the main role of red and orange carotenoid pigments may be to act as photoprotectants, and hypothesize that redness originated in the terrestrial ancestors of water mites and has been retained in certain lineages of water mites after the invasion of the aquatic habitat. We also suggest that distastefulness evolved subsequent to bright coloration in response to increased conspicuousness to predators. Relaxed selection for redness has occurred when adults and/or larvae are less exposed to sunlight, either through occupying more protected habitats, parasitizing more nocturnal hosts, or parasitizing hosts for a short period of time. Our ability to test this alternative hypothesis is hampered by lack of knowledge of the source and mode of action of distastefulness, and of phylogenetic relationships among the Parasitengona.

Animals↗
PubMed1995

Mite allergens in relation to home conditions and sensitization of asthmatic children from three climatic regions.

We investigated the levels of mite (Der p I and Der f I) allergen in dust from bedrooms, living rooms, kitchens, and bathrooms from 130 homes of asthmatic children in three climatic zones of Sweden. Bedroom dust samples included the child's mattress, carpets, floors, and other plain surfaces. Living-room dust samples were taken from sofas and other furniture, carpets, floors, and other plain surfaces. The allergen levels were related to home characteristics, including absolute indoor humidity (AIH), relative humidity (RH), and air changes per hour (ach). Mite allergen was detected in 62% of the homes. Levels of Der p I varied between < 16 ng and 50 micrograms/g dust, and Der f I between < 16 ng and 73 micrograms/g dust. Because we have designed a composite type of dust collection in our study, the allergen levels found tend to average down the results. Mite allergen levels were higher in homes with dampness problems, in homes with a smoker, and in homes without a basement. Homes with high absolute humidity (> or = 7 g/kg) or relative humidity (> or = 45%) and poor ventilation (< 0.5 ach) contained higher levels of mite allergens than homes with lower humidity and better ventilation. However, the number of ach measurements in homes was not high, and few homes had > 0.5 ach. Sensitization to house-dust mites was more common in southern than in northern and central Sweden. High levels of house-dust mite allergen in a temperate climate where mites are not ubiquitous are thus associated with dampness problems in homes and with tobacco smoking. Our data confirm and extend previous findings that high AIH and RH and poor ventilation increase the risk of mite infestation in homes. It seems to be important and necessary to control indoor humidity and ventilation levels, to avoid high mite allergen exposure in a temperate climate, because 34% of mite-sensitized asthmatic children were exposed to levels of mite allergen < 2 micrograms/g dust in their homes. The study also shows that mite allergen levels below the suggested threshold level (2 micrograms/g dust) are associated with mite sensitivity in children with perennial symptoms of asthma.

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