Mite Bodies Research Articles

Intraspecific variation of body size in a gamasid mite Laelaps clethrionomydis: environment, geography and host dependence.

We investigated intraspecific variation in body size of an ectoparasitic gamasid mite, Laelaps clethrionomydis, across 12 localities in the Palearctic. We asked whether mites collected from the same host species in different localities or from different host species in the same locality vary in body size. Within host species, mites collected in different localities differed significantly in body size, tending to be larger in northern than in southern localities. In addition, mite body size correlated negatively with mean annual temperature in a locality. Mites collected from different hosts in the same locality differed significantly in body size when hosts belonged to different genera but did not differ when collected from congeneric hosts. We conclude that intraspecific variation in mite body size is caused by interplay of environmental and host-related factors.

Digestive proteases in bodies and faeces of the two-spotted spider mite, Tetranychus urticae

Digestive proteases of the phytophagous mite Tetranychus urticae have been characterised by comparing their activity in body and faecal extracts. Aspartyl, cathepsin B- and L-like and legumain activities were detected in both mite bodies and faeces, with a specific activity of aspartyl and cathepsin L-like proteases about 5- and 2-fold higher, respectively, in mite faeces than in bodies. In general, all these activities were maintained independently of the host plant where the mites were reared (bean, tomato or maize). Remarkably, this is the first report in a phytophagous mite of legumain-like activity, which was characterised for its ability to hydrolyse the specific substrate Z-VAN-AMC, its activation by DTT and inhibition by IAA but not by E-64. Gel free nanoLC–nanoESI-QTOF MS/MS proteomic analysis of mite faeces resulted in the identification of four cathepsins L and one aspartyl protease (from a total of the 29 cathepsins L, 27 cathepsins B, 19 legumains and two aspartyl protease genes identified the genome of this species). Gene expression analysis reveals that four cathepsins L and the aspartyl protease identified in the mite faeces, but also two cathepsins B and two legumains that were not detected in the faeces, were expressed at high levels in the spider mite feeding stages (larvae, nymphs and adults) relative to embryos. Taken together, these results indicate a digestive role for cysteine and aspartyl proteases in T. urticae. The expression of the cathepsins B and L, legumains and aspartyl protease genes analysed in our study increased in female adults after feeding on Arabidopsis plants over-expressing the HvCPI-6 cystatin, that specifically targets cathepsins B and L, or the CMe trypsin inhibitor that targets serine proteases. This unspecific response suggests that in addition to compensation for inhibitor-targeted enzymes, the increase in the expression of digestive proteases in T. urticae may act as a first barrier against ingested plant defensive proteins.

Chemical basis of unwettability in Liacaridae (Acari, Oribatida): specific variations of a cuticular acid/ester-based system.

Oribatid mites of the family Liacaridae comprise a large number of species with smooth and shiny body surfaces that display extraordinary anti-wetting properties. The principle of liacarid unwettability is not related to micro-structured surfaces as present in many Oribatida ("Lotus effect") but the formation of raincoat-like lipid layers covering the epicuticle. We here conducted a comparative study on the chemistry of cuticular lipid layers in a selection of Liacaridae, including representatives of all major Central European genera, Liacarus, Dorycranosus, Adoristes, and Xenillus. Cuticular lipids of unwettable individuals were removed from mite bodies by hexane extraction, and were analyzed by GC-MS. Basically, two chemically distinguishable systems were found. Type I: cuticular lipids of Liacarus subterraneus, L. coracinus, L. nitens, Dorycranosus curtipilis, and Xenillus tegeocranus contained different carboxylic acids (C8-, C10-, C10:1-, C10:2-acids) and their corresponding di-glycerides in species-specific combinations. Type II: Adoristes ovatus exhibited a system of cuticular lipids composed of esters of pentanoic- and heptanoic acids with C14-, C15-, C16- and C17-alcohols. Interestingly, the chemistry of surface lipids did not reflect the morphology of the cuticle in the species investigated. Smooth and shiny cuticles, though exhibiting a specific pattern of round or slit-like pores, were found in representatives of Liacarus, Dorycranosus (all of which exhibiting cuticular chemistry of type I) and Adoristes (exhibiting cuticular chemistry of type II). Xenillus, possessing a rough, cerotegumental cement layer-covered surface, showed type I-chemistry. The acid-esters systems herein investigated are considered characteristic for the cuticular chemistry of Liacaridae or a lineage of these, and provide first insights into the comparative chemistry of the inner (=lipid) layer of the oribatid cerotegument.

<p class="HeadingRunIn"><strong>Do oribatid mites enhance fungal growth in <em>Austrocedrus chilensis</em> leaf litter?</strong></p>

The relation of particular species of Acari with soil functions regarding organic matter decomposition and nutrient recycling is not clear. Furthermore it is not known if distinguishable Acari species are more efficient to lead to an increase in the rate of mass loss of leaf litter or to favour the development of the microflora on leaf litter. We tackled this dilemma by growing selected mites on defaunated leaf litter of Austrocedrus chilensis. We tested for changes in the biomass of leaf litter in the presence or the absence of the mites. We used four species of oribatid mites which are usual inhabitants of the leaf litter of Austrocedrus chilensis in forests of Argentina´s Northwestern Patagonia: Anderemaeus magellanis, Cosmochthonius semifoveolatus , Lanceoppia kovacsi and Nothrus peruensis . After 3 months, the development of fungal growth in the presence of mites was evident. Containers with only C. semifoveolatus and L. kovacsi showed greater development of fungal biomass than those with A. magellanis or N. peruensis, evidencing specific differences in the enhancement effect. In the presence of C. semifoveolatus, mycelial diversity diminished with respect to the blank favoring only the development of septate brown hyphae of Ascomycota. We found no significant differences between the fungal growth enhancement provoked by L. kovacsi and C. semifoveolatus . Entanglement of fragments and propagules of fungi among the branched setae of C. semifoveolatus could account for the enhancement of fungal growth. Repeated contact of faster L. kovacsi specimens with mycelia and adherence of mycelial fragments and fungi propagules on mite bodies could account for the effect. Mite size was also related to the fungal growth enhancement as smaller mites were more efficient in fungal growth enhancement. Our results showed that fungal growth is more intensive in the presence of mites than in their absence and that oribatid mites have a role in shaping the communities of fungi in soil.

Der p 11 Is a Major Allergen for House Dust Mite-Allergic Patients Suffering from Atopic Dermatitis

House dust mites (HDMs) belong to the most potent indoor allergen sources worldwide and are associated with allergic manifestations in the respiratory tract and the skin. Here we studied the importance of the high-molecular-weight group 11 allergen from Dermatophagoides pteronyssinus (Der p 11) in HDM allergy. Sequence analysis showed that Der p 11 has high homology to paramyosins from mites, ticks, and other invertebrates. A synthetic gene coding for Der p 11 was expressed in Escherichia coli and rDer p 11 purified to homogeneity as folded, alpha-helical protein as determined by circular dichroism spectroscopy. Using antibodies raised against rDer p 11 and immunogold electron microscopy, the allergen was localized in the muscle beneath the skin of mite bodies but not in feces. IgE reactivity of rDer p 11 was tested with sera from HDM-allergic patients from Europe and Africa in radioallergosorbent test-based dot-blot assays. Interestingly, we found that Der p 11 is a major allergen for patients suffering from atopic dermatitis (AD), whereas it is only a minor allergen for patients suffering from respiratory forms of HDM allergy. Thus, rDer p 11 might be a useful serological marker allergen for the identification of a subgroup of HDM-allergic patients suffering from HDM-associated AD.

Mite species identification in the production of allergenic extracts for clinical use and in environmental samples by ribosomal DNA amplification

The identification of allergy-causing mites is conventionally based on morphological characters. However, molecular taxonomy using ribosomal DNA (rDNA) may be particularly useful in the analysis of mite cultures and purified mite fractions in the production of allergenic extracts. Full-length internal transcribed spacers (ITS1 and ITS2) were obtained from Dermatophagoides farinae, Dermatophagoides pteronyssinus, Dermatophagoides microceras and Euroglyphus maynei (Astigmata: Pyroglyphidae), Glycyphagus domesticus and Lepidoglyphus destructor (Astigmata: Glycyphagidae), Tyrophagus fanetzhangorum, Tyrophagus putrescentiae, Tyrophagus longior, Tyrophagus neiswanderi, Acarus farris and Acarus siro (Astigmata: Acaridae), and Blomia tropicalis (Astigmata: Echymopodidae), using mite-specific primers. Polymerase chain reaction (PCR) products were digested with HpaII and RsaI restriction enzymes in order to produce species-specific PCR restricted fragment length polymorphism (RFLP) profiles. A semi-nested re-amplification step was introduced before the RFLP in order to apply the method to environmental samples. Results demonstrate that rDNA sequences can be used for the unambiguous identification of mite species. The PCR-RFLP system allows the identification of species in purified mite fractions when the availability of intact adult mite bodies for morphological identification is limited. This reliable and straightforward PCR-RFLP system and the rDNA sequences obtained can be of use in the identification of allergy-causing mite species.

The body composition and enzymes of carbohydrate metabolism of Varroa destructor

Abstract The aim of the present research was to determine the basic composition of the organic compounds present in extracts from Varroa destructor, a parasitic mite of the honeybee. The total protein content was 9.16 ± 0.82 mg/100 mg of body weight, lipid content was 9.81 ± 1.99 mg/100 mg, and carbohydrate content was 26.67 ± 4.52 mg/100 mg. The triacylglycerol content was 2.40 ± 0.86 mg/100 mg and the cholesterol content was 0.14 ± 0.02 mg/100 mg. Thin layer chromatography indicated that phospholipids comprised the major part of the lipid component; cephalins (78%), cerebrosides (16%), and lecithins (6%) were identified in the phospholipid pool. Glucose (23.6 ± 4.52 mg/100 mg) was the main carbohydrate, followed by glycogen (5.43 ± 1.23 mg/100 mg) and trehalose (0.35 ± 0.07 mg/100 mg). Enzyme-linked immunosorbent assays detected two major glycogen metabolism enzymes, glycogen phosphorylase and glycogen synthase. Among the enzymes metabolising disaccharides, maltase (24.7 ± 2.38 μmol/mg protein) and trehalase (14.81 ± 5.21 μmol/mg protein) presented the highest activity. Saccharose and lactose were hydrolysed to a minor extent. These are the first measurements of the basic composition of the mite body. Although these data are not exhaustive, they may serve as the basis for further research on the metabolism of V. destructor, particularly concerning lipid metabolism.

Ecological correlates of body size in gamasid mites parasitic on small mammals: abundance and niche breadth

We studied ecological correlates of body size (abundance and niche breadth) in gamasid mites parasitic on small mammals in 28 regions of the Palearctic. We predicted that smaller species would be characterized by higher abundance than larger species, all else (e.g. host species) being equal. We also predicted that host specificity of mites would decrease (that is, number of host species they use would increase) with an increase in their body size. We focused on mites collected from host bodies that include a) species that feed solely on host’s blood (obligate exclusive haematophages), b) species that feed on both host’s blood and small arthropods (obligate non‐exclusive haematophages), and c) facultative haematophages. We expected that the relationship between body size and abundance and/or host specificity would be more pronounced in obligate exclusively haematophagous mites than for obligate non‐exclusively and facultative haematophagous mites. Across all mite species across regions, mean abundance correlated negatively with body size. The same was true for obligate haematophagous species, but not for facultative haematophages. When mite communities on the same host in a location were considered, the negative body mass–abundance relationship was found in only 3 of 44 communities. Nevertheless, a meta‐analytic (across host species) estimate of the slope of this relationship appeared to be significantly negative. No significant relationship between mite body size and host specificity was found in the analyses across all mite species as well as in obligate exclusive or obligate non‐exclusive haematophages. However, the number of hosts used by facultative haematophagous mites decreased significantly with an increase in their body size. We explain the relationships between morphological (body size) and ecological (abundance and niche breadth) properties of ectoparasites by their interactions with hosts or physical environment.

Body size and coexistence in gamasid mites parasitic on small mammals: null model analyses at three hierarchical scales

We studied body size ratio in gamasid mites (Acari: Mesostigmata) parasitic on Palearctic small mammals at 3 hierarchical scales, namely infracommunities (an assemblage of mites harboured by an individual host), component communities (an assemblage of mites harboured by a host population), and compound communities (an assemblage of mites harboured by a host community). We used null models and asked a) whether body size distributions in these communities demonstrate non‐random patterns; b) whether these patterns indicate segregation or aggregation of body sizes of coexisting species; and c) whether patterns of body size distribution are scale‐dependent, that is, differ among infracommunities, component communities, and compound communities. In most mite assemblages, the observed pattern of body size distribution did not differ from that expected by chance. However, meta‐analyses demonstrated that component and compound communities of gamasid mites consistently demonstrated a tendency to reduced body size overlap, while we did not find any clear trend in mite body size distribution across infracommunities. We discuss reasons for scale‐dependence of body size distribution pattern in parasite communities and propose ecological and evolutionary mechanisms that allowed the reduced body size overlap in component and compound communities of ectoparasites to arise.

Population growth and allergen accumulation of Dermatophagoides farinae cultured at 20 and 25 °C

House dust mites are cultured to obtain mite allergen material to produce allergen extracts (vaccines) for diagnostic tests, immunotherapy, and research purposes. Research laboratories and manufacturers have their own culturing protocols to grow these mites and these may vary between manufacturers and between research laboratories. The temperature at which mites are cultured may influence the allergen composition, allergen ratio of Der 1: Der 2 and endotoxin levels in the extracts produced from these cultured mites. In order to produce standardized and uniform extracts, across the industry and in various research laboratories, the influence of culture conditions must be understood. Here we determined how temperature affects mite population growth rates, dynamics of allergen production, Der f 1: Der f 2 ratio and endotoxin levels in extracts made from Dermatophagoides farinae mites cultured at 20 and 25°C. We found that Der f 1 and Der f 2 accumulated exponentially in the cultures with Der f 1 accumulating faster than Der f 2. When the live mite populations peaked, the ratios for Der f 1: Der f 2 were 4.1 and 4.7 for cultures reared at 20 and 25°C, respectively. Most of the Der f 1 and Der f 2 allergen in whole cultures is not in mite bodies and is lost when the mite material is washed. Thus, if the ratio of Der f 1 and Der f 2 is an important consideration for commercial and research extracts, then the temperature at which the mites are cultured and the collection procedure are important considerations.

Feather mites (Acari: Astigmata) and body condition of their avian hosts: a large correlative study

Feather mites are arthropods that live on or in the feathers of birds, and are among the commonest avian ectosymbionts. However, the nature of the ecological interaction between feather mites and birds remains unclear, some studies reporting negative effects of feather mites on their hosts and others reporting positive or no effects. Here we use a large dataset comprising 20 189 measurements taken from 83 species of birds collected during 22 yr in 151 localities from seven countries in Europe and North Africa to explore the correlation between feather mite abundance and body condition of their hosts. We predicted that, if wing‐dwelling feather mites are parasites, a negative correlation with host body condition should be found, while a mutualistic interaction should yield positive correlation. Although negative relationships between feather mite abundance and host body condition were found in a few species of birds, the sign of the correlation was positive in most bird species (69%). The overall effect size was only slightly positive (r =0.066). The effect of feather mite abundance explained <10% of variance in body condition in most species (87%). Results suggest that feather mites are not parasites of birds, but rather that they hold a commensalistic relationship where feather mites may benefit from feeding on uropygial gland secretions of their hosts and birds do not seem to obtain a great benefit from the presence of feather mites.

Statistical approaches to assess intraspecific variations of morphological continuous characters: the case study of the family Phytoseiidae (Acari: Mesostigmata).

Statistical methods for delimiting species with morphological data remain woefully understudied. The present study presents statistical approaches to study the intraspecific variations of continuous characters used in species diagnosis. For this, the data set comprised 14 species of the mite family Phytoseiidae (Acari: Mesostigmata) and 23 continuous characters (seta lengths). The statistical approaches aim to determine (i) how intraspecific variations differ depending on the characters and species considered, and (ii) how to choose the number of specimens to be considered for characterizing intraspecific boundaries. The means of the related confident limits at 95% (rCL95 ) of the 14 species and the 23 setae are around 20%, suggesting that 95% of the specimens of a same species are included in the interval μ ± 0.2μ. No relationship was found between seta variations and the number of specimens considered for each species, nor for seta variations and their position on the mite body. However, a correlation between seta lengths and rCL95 means was observed. An abacus was proposed to determine the coefficient that must be applied to mean seta length to calculate the lower and upper limits of the interval that will include 95% of the specimens of a same species. The higher the precision around the mean, the higher the number of specimens considered. Furthermore, this number varies considerably depending on the characters and species considered for high precisions. However, for a priori error around the mean of 15%, the number of specimens needed to characterize the intraspecific variation is quite homogeneous and ten specimens would be required. I discuss the utility of such results to resolve some persistent problems in the alpha-taxonomy of the family Phytoseiidae but also of other taxa. © The Willi Hennig Society 2012.

Anatomy and fine structure of pedicellar glands in phoretic deutonymphs of uropodid mites (Acari: Mesostigmata)

Phoretic deutonymphs of uropodid mites are attached to their carrier via an anal pedicel which is formed by a secretion from the pedicellar gland. Since the ultrastructure of the pedicel and pedicellar gland has never been investigated, we studied these structures in three species, Uropoda orbicularis (Müller), Uroobovella marginata (Koch), and Trichouropoda ovalis (Koch) by light (LM) and electron microscopy (TEM, SEM). In addition, the pedicel in Uroobovella nova (Oudemans) was documented in SEM.The pedicellar gland is a distinct globular structure comprised of three types of secretory cells (A-, B-, and C-types) with apical parts directed towards a junctional zone of postcolon and anal atrium. Secretory cells of the A-type are located dorsally, whereas B-type cells are central, and C-type cells are distributed ventrally or both ventrally and dorsally. Protrusions of visceral muscle cells are distributed on the external surface of the gland. The cuticle-lined anal atrium is large and located between the gland and dorso-anal muscles. The pedicel is composed of a main stalk and two extended extremities: one adhering to the anal region of the deutonymph and a second connected to the cuticle of the carrier. In each case, the anal atria were empty, whereas the pedicellar material was located outside of the mite body.

Identification of prey consumed by Stethorus punctum picipes (Casey) (Cleoptera: Coccinellidae) in tree fruit and vines in Washington State, USA

ABSTRACT To determine the type of prey consumed by the predatory coccinellid, Stethorus punctum picipes (Coleoptera: Coccinellidae), we identified food remains, based on body parts or whole bodies of mites, in the guts of adults collected in two fruit orchards (apple and cherry) and one vineyard in Washington State, United States in August and September 2009. Various plant-inhabiting mites, including species in the families Stigmaeidae, Eriophyidae, Phytoseiidae, and Tetranychidae, were found in guts of S. p. picipes collected on grapevine where no tetranychids were observed. On apple, where tetranychids were abundant, gut contents contained Tetranychidae, Stigmaeidae, and Eriophyidae. On cherry, where tetranychids were abundant, only Tetranychidae were found in gut contents. These results indicate that S. p. picipes adults can feed on alternative plant-inhabiting mites, in particular, when tetranychids are scarce.

Detection ofOrientia tsutsugamushi, the Causative Agent of Scrub Typhus, in a Novel Mite Species,Eushoengastia koreaensis, in Korea

To identify potential vector species of scrub typhus in the Republic of Korea (ROK), chigger mites were harvested from wild rodents captured at nine localities in October 2005. The bodies of the chigger mites were individually punctured with a fine pin, squeezed out internal contents, and examined for Orientia tsutsugamushi DNA by nested polymerase chain reaction. The exoskeleton of associated chiggers was mounted on glass slides with polyvinylalcohol (PVA) medium for identification. Among 830 individuals belonging to 4 genera and 14 species, O. tsutsugamushi was detected from 22 chiggers of six species, with an overall infection rate of 2.7%. The infection rate was highest for Leptotrombidium palpale (5.3%), followed by Neotrombicula japonica (4.3%), Leptotrombidium scutellare (3.7%), Leptotrombidium orientale (3.6%), Eushoengastia koreaensis (1.9%), and Leptotrombidium pallidum (1.5%). This study first reported O. tsutsugamushi infection from N. japonica and E. koreaensis larvae in the ROK. The population densities of L. pallidum (33.4 chiggers/rodent), historically confirmed as a primary vector of scrub typhus in the ROK, were high, whereas its infection rate was relatively low (1.5%). However, E. koreaensis was only collected from 154 individuals at seven collection sites and its infection rate was demonstrated relatively high (mean 1.9%). Additional studies are needed to determine the role of vector species in the epidemiology of scrub typhus.

Impact of Dermatophagoides pteronyssinus mite body raw material on house dust mite allergy diagnosis in a Serbian population

House dust mite (HDM) allergy has different clinical and immunological patterns in different geographic regions. The impact of raw material of commercial Dermatophadoides pteronyssinus (Acari: Pyroglyphidae) mite bodies on the quality of allergen extracts for allergy diagnosis in the Serbian population has not been previously evaluated. House dust mite bodies obtained from manufacturers in Europe, South America and Australia were used in the preparation of allergen extracts for in vivo diagnosis and serological analysis in a group of 14 HDM-allergic adults. In the group of mite-allergic patients, there was no statistically significant difference in skin test reactivity (Wilcoxon matched pairs test) among the three HDM body extract preparations. In a CAP inhibition assay, two extracts (A and C) achieved maximum inhibition of >90%, whereas extract B demonstrated a different inhibition slope and lower inhibition potential (80%). However, a remarkable difference in immunoglobulin E reactivity using Western blot analysis with individual patients' sera was observed in one of the preparations (extract B). These findings emphasize the need for the careful selection of starting material for the preparation of HDM diagnostic reagents intended for use in patients from geographically distinct regions as these preparations can have implications on the selection criteria for patient-tailored immunotherapy of HDM allergy.

Flaky Tail Mouse Denotes Human Atopic Dermatitis in the Steady State and by Topical Application with Dermatophagoides pteronyssinus Extract

The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. Flaky tail (Flg(ft)) mice, essentially deficient in filaggrin, have been used to investigate the role of filaggrin on AD. However, the relevancy of Flg(ft) mice to human AD needs to be determined further. In this study, we observed the clinical manifestations of Flg(ft) mice in the steady state and their cutaneous immune responses against external stimuli, favoring human AD. Under specific pathogen-free conditions, the majority of Flg(ft) mice developed clinical and histological eczematous skin lesions similar to human AD with outside-to-inside skin barrier dysfunction evaluated by newly devised methods. In addition, cutaneous hapten-induced contact hypersensitivity as a model of acquired immune response and a mite extract-induced dermatitis model physiologically relevant to a human AD were enhanced in Flg(ft) mice. These results suggest that the Flg(ft) mouse genotype has potential as an animal model of AD corresponding with filaggrin mutation in human AD.

Monoclonal antibodies against recombinant Der f 3 reveal localization of Der f 3 in the gut and faecal pellets of Dermatophagoides farinae

Home dust mite derived materials are known to be a major source of problematic inhalant allergens. The aim of this study was to determine the localization of the group 3 allergen, Der f 3, within Dermatophagoides farinae, in order to assess the relative importance of excreted materials and nonexcreted body components as allergen sources. Recombinant Der f 3 (rDer f 3) was expressed in bacteria and purified as an immunogen for production of monoclonal antibodies (mAb) against it. Dermatophagoides farinae mites and their faecal pellets were embedded in paraffin, and serial sections were immunoprobed with mAb clone 3D3 against Der f 3. D. farinae midgut mucosa, gut contents and faecal pellets were strongly immunopositive for Der f 3. Der f 3 immunoreactive products were not detected in any other internal organs of the mite. These results suggest that Der f 3 allergen may be synthesized in and secreted from the digestive tract and excreted from the mite's body in the faecal pellets.

Stability evaluation of house dust mite vaccines for sublingual immunotherapy

Allergen-specific immunotherapy with house dust mite (HDM) allergen extracts can effectively alleviate the symptoms of allergic rhinitis and asthma. The efficacy of the immunotherapeutic treatment is highly dependent on the quality of house dust mite vaccines. This study was performed to assess the stability of house dust mite allergen vaccines prepared for sublingual immunotherapy. Lyophilized Dermatophagoides pteronyssinus (Dpt) mite bodies were the starting material for the production of sublingual vaccines in four therapeutic concentrations. The stability of the extract for vaccine production, which was stored below 4 ?C for one month, showed consistence in the protein profile in SDS PAGE. ELISA-inhibition showed that the potencies of Dpt vaccines during a 12 month period were to 65-80 % preserved at all analyzed therapeutic concentrations. This study showed that glycerinated Dpt vaccines stored at 4?C preserved their IgE-binding potential during a 12 month period, implying their suitability for sublingual immunotherapeutic treatment of HDM allergy.

Effect of an Air Cleaner with Electrostatic Filter on the Removal of Airborne House Dust Mite Allergens

PurposeThe effects of air cleaners on the removal of airborne indoor allergens, especially house dust mites (HDM), are still controversial. The objective of this study is to evaluate the effect of an air cleaner with an electrostatic filter on the removal of airborne mite allergens.Materials and MethodsA dried HDM culture medium that contained mite body particles and excretions was dispersed in a chamber equipped with an electrostatic air cleaner. The number of airborne particles was recorded continuously by a dust spectrometer for 60 minutes. Airborne particles in the chamber were collected on a sampling filter at a flow rate of 10 L/min and the Der f 1 concentration in the filter extracts was measured by two-site ELISA.ResultsThe air cleaner efficiently removed airborne HDM particles. The air cleaner removed airborne HDM particles (size 2-12.5 µm) 11.4 ± 2.9 fold (cleaner operating for 15 minutes), 5.4 ± 0.7 fold (cleaner operating for 30 minutes), and 2.4 ± 0.2 fold (cleaner operating for 60 minutes) more than the removal of HDM particles by natural settle down. Removal kinetics differed according to the particle size of the airborne particles. The air cleaner decreased the concentration of Der f 1 in the extraction of airborne particles collected on the air sampling filter by 60.3%.ConclusionThe electrostatic air cleaner can remove airborne HDM allergens and may be useful as a supplementary environmental control tool for HDM sensitized respiratory allergic patients.