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At least 73 records · Page 4Linked to original sources
PubMed2002

Biological control of spider mites on grape by phytoseiid mites (Acari: Tetranychidae, Phytoseiidae): emphasis on regional aspects.

Leaf samples were taken from 34 (1998) and 10 (1999) vineyards in five valleys in western Oregon to assess spider mite pests and biological control by predaceous phytoseiid mites. A leaf at a coordinate of every 10 m of border, 5 m into a vineyard, was taken to minimize edge effects; 20 leaves were taken at regular intervals from vineyard centers. Variables recorded at each site included grape variety and plant age, chemicals used, and vegetation next to vineyards. Sites were rated as occurring in agricultural versus riparian settings based on surrounding vegetation types. Multiple linear regressions and a computer genetic algorithm with an information content criterion were used to assess variables that may explain mite abundances. Typhlodromus pyri Scheuten was the dominant phytoseiid mite species and Tetranychus urticae Koch the dominant tetranychid mite species. High levels of T. urticae occurred when phytoseiid levels were low, and low levels of T. urticae were present when phytoseiid levels were high to moderate. T. urticae densities were higher in vineyards surrounded by agriculture, but phytoseiid levels did not differ between agricultural and riparian sites. Phytoseiids had higher densities on vineyard edges; T. urticae densities were higher in centers. Biological control success of pest mites was rated excellent in 11 of 44 vineyards, good in 27, and poor in only six sites. Predaceous mites appeared to be the principal agents regulating spider mites at low levels in sites where pesticides nontoxic to predators were used. Effects of surrounding vegetation, grape variety, growing region, and other factors on mites are discussed.

Animals↗
PubMed1990

Hyposensitization in asthmatics with mPEG-modified and unmodified house dust mite extract. III. Effect on mite-specific immunological parameters and correlation to changes in mite-sensitivity and symptoms.

Forty-six adult asthmatics allergic to D. pteronyssinus (Dp) participated in a 2-year study. Thirty-one underwent hyposensitization (HS-group). Fifteen were treated with Dp-extract (Dp-group), and 16 with a similar extract modified by monomethoxypolyethylene glycol with reduced allergenicity (mPEG-Dp-group). Fifteen patients served as controls. Dp-specific antibodies and histamine release from blood basophils were determined and compared with Dp-sensitivity in lungs and skin. In addition, IgG and IgE against the major allergen Der p I were followed in a subgroup. Dp-specific IgG, IgG1, and IgG4 increased significantly in both HS-treated groups after 1 and 2 years (median: 2.5- to 11.6-fold). IgG4 was not induced if maintenance dose during the first year was less than 20,000 BU. Median skin sensitivity decreased 4.4- to 8.2-fold after 1 year and 7.4- to 21.4-fold after 2 years. Der p I specific IgG response was unrelated to the occurrence or change in IgE with the same specificity. The mPEG-Dp-extract tended to have less effect on skin sensitivity and immunological parameters, differences reaching statistical significance for skin sensitivity only. In the HS-group, the decrease in bronchial sensitivity was significantly correlated to a decrease in IgE (r = 0.36), IgG1/IgG4 (r = 0.49), Dp-specific histamine release (r = 0.58), and to an increase in Dp-specific IgG4 (r = -0.36) and IgG4/IgE (r = -0.48). In patients improving clinically, Dp-specific IgG4/IgE increased, and median Dp-specific IgE was reduced to 80% compared with an increase to 150-160% seen in the unchanged or deteriorated group (P less than 0.05). Findings indicate an improvement of effect, if the allergen dose is sufficient to reduce specific IgE and/or induce an IgG and especially IgG4 response.

Adult↗
PubMed2006

Mite penetration of different types of material claimed as mite proof by the Siriraj chamber method.

BACKGROUND: There are different materials and principles used in the construction of bed encasings. Although these covers claim to have antimite properties, they might not be mite proof. OBJECTIVE: This study evaluated the effectiveness of mite penetration of these covers by using the Siriraj chamber method. METHODS: Thirty-two covers collected from 9 different countries were categorized according to the materials used to manufacture them. They were (1) tightly woven, (2) film or membrane coated and loosely woven, (3) acaricidal coated and loosely woven, (4) nonwoven, (5) film coated and nonwoven, (6) acaricidal coated and nonwoven, and (7) plastic. Adult mites, Dermatophagoides pteronyssinus, were placed on either the outer or inner surfaces of each of the test fabrics for 3 replications, resulting in a total of 6 samples per fabric. All samples were observed for penetration every day for 1 week under a stereomicroscope. If a single mite penetrated any fabric, it was scored as a penetration. RESULTS: Mites penetrated (1) into all samples of film-coated woven and nonwoven covers, an acaricide-coated nonwoven cover, and nonwoven types; (2) from both sides and colonized within the matrix of some samples; and (3) completely in other cases. All of the woven covers and the plastic cover prevented mite penetration. Photomicrographs documented all penetrations. CONCLUSIONS: Tightly woven covers and plastic prevent mite penetration, whereas nonwoven, loosely woven, acaricide-coated, and laminated materials do not. The Siriraj chamber method adequately evaluates the effectiveness of antimite barriers. CLINICAL IMPLICATIONS: For mite avoidance, allergists should recommend the use of tightly woven covers on suspected bedding containing dust mites.

Animals↗
PubMed1993

Mite-allergen exposure and spontaneous histamine release in monosensitive and polysensitive mite-allergic patients.

Forty-three patients allergic to mites and suffering mainly from asthma were recruited: 25 were mite-monosensitive and 18 were polysensitive, as determined by skin tests and specific serum IgE determinations with various allergens. In vitro spontaneous histamine release (SHR) by washed blood basophils was measured once or several times for each patient. Throughout this study, the mean periods of high and low mite-allergen exposure were defined on the basis of relative indoor humidity and temperature data. For the mite-monosensitive patients, there was a significant increase in mean SHR during the season of high mite-allergen exposure as compared to the months of lower mite-allergen presence (P < 0.002). No significant difference between mean SHR values was observed when comparing the monosensitive group during the season of high mite-allergen exposure with polysensitive patients (allergic to mite and pollen) during the period of exposure to both allergens. Differences in mean SHR reported here emphasize the positive relationship between intense allergen exposure and the in vitro SHR increase in blood basophils of mite-allergic patients.

Adult↗
PubMed2006

Laboratory studies on the use of two new arenas to evaluate the impact of the predatory mites Blattisocius tarsalis and Cheyletus eruditus on residual populations of the stored product mite Acarus siro.

Residual populations of storage mites sheltering in crevices and cracks escape conventional control treatments and are implicated in the infestation of newly harvested grain. In a series of 24 h laboratory tests, the performance of solitary adults of two predatory mite species, Cheyletus eruditus (Schrank) and Blattisocius tarsalis (Berlese), were assessed for controlling small numbers of the flour mite Acarus siro (L.). Tests were carried out in the presence or absence of prey refuges or grain debris to afford shelter to the flour mites. While C. eruditus had a significant effect on the motile stages of A. siro, in contrast B. tarsalis had a significant effect on the eggs. The maximum percentage of motile stages of A. siro eaten by C. eruditus was 82%, whereas the minimum percentage of A. siro eggs eaten by B. tarsalis was 99%. While the performance of C. eruditus in predating on motile stages of the flour mite was hindered by the presence of the prey refuge (38% eaten) and grain debris (25% eaten), the performance of B. tarsalis in predating on flour mite eggs was unaffected (100% eaten in presence of prey refuge or grain debris). In prolonged exposures (36 days) the performance of 2, 4 or 8 adult predators, either a single species or a combination of both, was assessed for their ability to control a population of the flour mite developing up to F(2) from an initial inoculum of 80 females and 20 males, allowed to oviposit for 72 h in the absence of predatory mites. The maximum reduction in prey population of 80% was achieved with eight B. tarsalis. Combining the two predatory species did not enhance the reduction of A. siro population.

Animals↗
PubMed2003

Medical Indoor Environment Counselor (MIEC): role in compliance with advice on mite allergen avoidance and on mite allergen exposure.

BACKGROUND: In order to improve patient compliance in allergen avoidance, a new occupational activity was created: Medical Indoor Environment Counselor (MIEC). The aim of this study was to assess the impact of an MIEC on compliance with advice for mite allergen reduction in patients sensitized and exposed to mite allergens, and on mite allergen levels. METHODS: The study included 378 patients from four centers (Marseilles, Montpellier, Paris, Strasbourg) in a randomized prospective study. Patients in group A received advice from doctors only, and those in group B from doctors and MIEC. Mite allergen levels were measured on mattresses, mattress bases, and floors. Compliance and mite allergen levels were assessed 5 months later. RESULTS: Compliance for changing the mattress bases, removing or treating the carpets, washing duvets, pillows and stuffed animals were significantly higher in group B than in group A. A significant decrease in mite allergen was obtained for group B in mattress bases (83.8-22.9 micro g/g) and in carpets (15.8-6.3 micro g/g), but not in group A. CONCLUSION: Our results suggest that the home visit by the MIEC 1) increased the compliance to mite reduction methods advised; 2) induced a significant difference in mite reduction levels on mattress bases and on carpets; 3) avoided nonestablished avoidance advice.

Adolescent↗
PubMed1992

Mechanisms and patient compliance of dust-mite avoidance regimens in dwellings of mite-allergic rhinitic patients.

We report on the mechanisms, the environmental changes and patient compliance with regard to conventional and new dust and mite avoidance measures to prevent allergic symptoms caused by mite allergens, taking into account both allergen contamination and the developmental success of pyroglyphid Acari. Twenty patients with persisting rhinitic complaints were selected and matched. Although the patients had performed some conventional dust and mite avoidance measures (patient compliance was 90%), the dwellings proved to be a stimulus for mite development. Moisture problems due to faulty construction and excessive moisture production were common. Since humidity conditions could not be changed at short notice, the 20 homes were subjected to the new variants of mite allergen avoidance based on intensive cleaning without (control) and with an acaricide incorporated (acaricidal cleaner [Acarosan]). After the carrying out of conventional avoidance measures, these patients still had allergic symptoms, and dust from only 23 to 52% of their textile objects was under the proposed guanine (mite faeces indicator) risk level. Only the acaricidal cleaner was able to decrease the allergenic mite load (and the burden of the patients) significantly in this 12 month period. With respect to mite-extermination, acaricidal cleaning was 88% better than intensive cleaning. Reduction of guanine was 38% better in the Acarosan treatment group. Clinical results have been reported elsewhere. A significant difference in favour of the acaricidal cleaning was seen in both subjective (as regards symptoms) and in objective data (total IgE). Another 50 patients were questioned.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1996

Reduction in humidity as a method of controlling mites and mite allergens: the use of mechanical ventilation in British domestic dwellings.

BACKGROUND: Low humidity is an important limiting factor for mite population growth. Reducing humidity can therefore be used as a method to control mites within the home. OBJECTIVE: This study investigated the effect of mechanical ventilation heat recovery (MVHR) units on house dust mites and mite allergen Der p 1 in typical homes in the North-West of England. METHODS: Mite counts and Der p 1 levels were measured at 3-monthly intervals over a period of 1 year in 18 houses (nine with MVHR units and nine architecturally matched control houses). Paired dust samples were collected using a vacuum cleaner with an air-flow rate 451/sec, adapted to collect the sample onto a preweighed filter paper. A 1 m2 area of bedroom carpet, living room carpet and mattress was sampled for 2 min. Indoor temperature and relative humidity (RH) levels were recorded for a period of 1 week before and after the winter period (November and February: 3 and 6 months data sets). The environmental questionnaire was completed at the beginning and at the end of the study. RESULTS: No difference in either Der p 1 concentrations or mite counts in any of the sampling sites at 3, 6, 9 and 12 months as compared with the baseline values was found, both within and between the groups (P > 0.01). The measured levels of RH performed in autumn and winter were found to be lower in the MVHR houses compared to the architectural controls. The indoor temperature during each period did not differ between the groups. Questionnaire data showed that the severity of condensation improved in the MVHR homes, whilst during the winter period, the severity of condensation had increased in the architectural control group. CONCLUSIONS: The MVHR unit does not reduce indoor humidity to levels capable of retarding the mite population growth and decreasing mite allergens in the type of houses predominantly found in the mild and humid climate of the North-West of England.

Allergens↗
PubMed1996

ELISA method for detection of mite allergens in barn dust: comparison with mite counts.

ELISA (enzyme-linked immunosorbent assay) inhibition with a monoclonal antibody (mAb) (42B6) to Lepidoglyphus destructor was used to detect and quantify the storage-mite allergens in 30 dust samples collected from barns. Regarding the mite fauna, microscopic inspection of the barn dust and mite counts showed that L. destructor infested all 30 barns investigated (range 430-195 400 mites/g dust). In 29/30 barns, L. destructor constituted more than 70% of the Astigmata species. Acarus siro was found in 26 samples, the highest value being 16155 mites/g. No Dermatophagoides species were found. As to mites of the suborder of Prostigmata, species belonging to seven different families were detected. Besides the predominant L. destructor, allergens derived from other storage mites such as Glycyphagus domesticus, A. siro, and Tyrophagus putrescentiae have previously been assessed by this ELISA method. The correlation between number of mites and concentrations of mite antigen as measured by ELISA was assessed by linear regression (r2 = 0.83). Thus, inhibition of mAb 42B6 in ELISA would seem to offer a simple and reliable method to detect levels of dust-mite species belonging to the Acaridae and Glycyphagidae families.

Agricultural Workers' Diseases↗
PubMed1998

Life cycle and reproduction of house-dust mites: environmental factors influencing mite populations.

An understanding of the life cycle of house-dust mites, as well as environmental factors influencing mite populations, can be exploited in mite control. The most important limiting factor for house-dust-mite populations is air humidity. House-dust mites osmoregulate through the cuticle and therefore require a high ambient air humidity to prevent excessive water loss. In addition, the supracoxal glands actively take up ambient water vapour, and the protonynph stage of the life cycle is resistant to desiccation. Larger house-dust-mite populations are found when the absolute indoor air humidity is above 7 g/kg (45% relative humidity at 20 degrees C). Consequently, ventilation by air-conditioning systems is being developed as a means of control. A number of other aspects of the domestic environment are also being manipulated in an integrated approach to render the habitat less suitable for mites. The potential exists for developing models for house-dust mite populations, environmental characteristics, and the effects of various approaches to control.

Animals↗
PubMed1981

Anti-mite IgE antibody production in vitro by peripheral blood lymphocytes from mite-sensitive atopic patients.

Anti-mite IgE antibody production in vitro was investigated using peripheral blood lymphocytes (PBL) from mite-sensitive patients with bronchial asthma. Preculture of PBL with the mite antigen, which induced the remarkable cell proliferation, resulted in a marked decrease of the IgE antibody production directed to mite but not to unrelated antigens. Anti-mite IgE antibody formation was not inhibited by autologous or allogeneic T cells stimulated with the mite antigen. The spontaneous production of IgE antibody was observed when fractionated B cells were cultured alone or with pokeweed mitogen (PWM), but was suppressed when they were precultured with the antigen. Coculture of autologous T cells with B cells showed a considerable augmentation of anti-mite IgE antibody formation. The enhancing activity of autologous T cells was not observed when B cells were irradiated at 1,000 rad. The spontaneous IgE antibody production by B cells alone was radioresistant. Both mitotic inhibitors and 1,000 to 2,000 rad of gama-irradiation did not significantly suppress the spontaneous anti-mite IgE antibody production by B cells.

Antigens↗
PubMed2002

[Distribution of hemorrhagic fever with renal syndrome virus in gamasid mites and chigger mites].

OBJECTIVE: To study the distribution of hemorrhagic fever with renal syndrome virus (HFRSV) in mites. METHODS: In situ reverse transcription-polymerase chain reaction (IS RT-PCR) was used for detecting the distribution of HFRSV in mites. RESULTS: HFRSV RNA was mainly located in ovary and mid-gut tissues of gamasid mites and chigger mites. The positive signal intensity in the third and fourth generations of gamasid mite was stronger than that in the first and second generations, and that in nymph of chigger mite more than larva. CONCLUSION: Both chigger mite and gamasid mite could play an important role in the transmission of HFRSV.

Animals↗
PubMed1990

House dust mites and atopic dermatitis. A case-control study on the significance of house dust mites as etiologic allergens in atopic dermatitis.

The occurrence of house dust mites was measured in homes of 24 patients with atopic dermatitis, 30 patients with mite-sensitive asthma and 32 patients with asthma not related to house dust mites. Patients with mite-positive asthma and patients with atopic dermatitis had significantly higher exposure to house dust mites compared with patients with mite-negative asthma. For atopic dermatitis the higher exposure to house dust mites corresponded to a relative risk of 4.7 and a clear dose-response relationship was demonstrated between exposure and risk of disease in the subgroups of patients with atopic dermatitis. The present epidemiologic results support the idea that house dust mites may be an etiologic factor in a proportion of adult patients with atopic dermatitis.

Allergens↗
PubMed1977

[The importance of house dust mites and stored food mites as house dust allergens in the rural population].

House dust samples from rural districts contain more mite species (in particular stored food mites) than samples from urban areas, and the total number of mites is also approximately three times greater. 77 patients from rural districts, 48 of whom allergic to their own house dust, and 29 controls, were tested with mite extracts from Dermatophagoides pteronyssimus, D. farinae, Chortoglyphus arcuatus, Acarus siro, Glycyphagus destructor and Tyrophagus putrescentiae, and a house dust extract. Out of 32 patients who showed positive scratch tests to one or more mite extracts, 29 (90,6 percent) reacted positively to D. pteronyssimus, 25 (78.1 percent) to D. farinae and from 7 to 12 (20-40 percent) to the stored food mites. Out of the 48 patients allergic to their own house dust, 27 (56.2 percent showed positive reactions to D. pteronyssinus, 24 (50.0 percent) to the house dust extract and 21 (43.7 percent) to D. farinae. Only 5 (17.2 percent) out of the 29 controls reacted positively to one or more of the solutions tested. The stored food mites showed 2.5 to 4.5 times more positive reactions in the rural patients compared with the results obtained in urban patients. The importance of these mites in the sensitization of patients from rural districts is discussed.

Adolescent↗
PubMedDate not supplied

Effects of Microstop-treated anti-mite bedding on children with mite-sensitive asthma.

Seventy-one children with mite-sensitive asthma were randomly divided into three groups. Group 1 was comprised of 28 patients who were provided with new Microstop-treated bedding including matresses, quilts, pillows, bed linens and quilt covers. The Microstop mattresses and pillows were made of impermeable Polyurethane coated nylon ticking. Group 2 included 28 patients who were provided with new, conventional, mat Polyurethane mattresses, quilts, pillows, bed linens and quilt covers made of cotton and polyester which had not been Microstop treated. Group 3 included 15 patients who used their old bedding. Mite counts were performed on samples of dust collected from the old mattresses, pillows and quilts before the bedding was changed. After changing the bedding, mite counts were performed on dust from the same three bed sites at the end of months 1, 2, 3, 6, 9, and 12. Morning and evening peak expiratory flow, asthma symptom scores, were recorded by each patient at least 1 month before entering the study and every month during the one-year study period. Mattress mite counts were significantly reduced in Group 1 but not in Groups 2 or 3. However, quilt mite counts were significantly reduced in both Group 1 and Group 2 throughout the 12-monthstudy while mite counts in Group 3 quilts remained unchanged. The results provide evidence that the PU-coated nylon material was effective in reducing house dust mites, but do not demonstrate that the Microstop treatment had an obvious anti-mite effect. One-year follow-up of asthma symptom scores showed significant improvement in Group 1, but not in Groups 2 or 3. This suggests that the Microstop-treated bedding, as a system, was effective in asthma prevention.

Adolescent↗
PubMed1998

The relation between scabies and hypersensitivity to antigens of house dust mites and storage mites.

Twenty five non-atopic scabietic patients were examined to estimate their reaction to crude house dust mite Dermatophagoides farinae (D. farinae) and storage mite Tyrophagus putrescentia (T. putrescentiae) antigens. Skin prick testing (SPT) by extracts of both mites antigens showed significant higher positive results in scabietics when compared to non-scabietic control subjects. Moreover, 60% and 56% of scabietic patients showed positive levels of specific anti-D. farinae and T. putrescentia IgE respectively in comparison to 13.4% & 20% of control subjects. A significant difference has been obtained when the total number of positive results were compared to the total number of negative ones. The results revealed that there is an evidence of cross reactivity between Sarcoptes scabiei antigens and extracts of D. farinae and T. putrescentiae, and the hypersensitivity to house dust mite and storage mite antigens was significantly higher in scabietics than in controls. It could be concluded that there is some proof that other mites rather than Sarcoptes scabiei may have a role in the pathogenesis of scabies and the cross reactivity between S. scabiei and house dust mite and storage mite may explain the persistence of symptoms in some cases even after proper treatment of the disease.

Adolescent↗
PubMed2005

A new versatile and robust mite trap for detection and monitoring of storage mites in the cereal and allied industries.

Storage mites are important primary pests but present methods for trapping them are either rudimentary or have several limitations. These prevent effective early detection or reliable monitoring of mites in the food, animal feed and associated industries. The BT Trap is the first trap designed specifically for the detection and monitoring of mite infestation. This trap is made up of a mixed food base lure held in a robust adjustable housing. It is user friendly, requires an exposure period of only 4 days and can be used in a dusty environment. The performance of the BT Trap was evaluated in the laboratory and the mean minimal capture rate of mites was 62%. In a comparative field trial, this trap detected significantly more mites than the bait bag or the fishmeal trap. The trap's performance was also assessed in four different types of premises. These were premises engaged in the production of cereal based dry pet food, specialist animal feed, traditional cheese, and in the finished cereal section of a large transit storage warehouse. A total of 17 genera or species of storage and predatory mites was detected in these four premises, with at least seven species detected in each of these premises. This study confirms that the BT Trap was able to function under the rigours of use in the field. It has demonstrated its potential as a useful tool for early detection and monitoring of mites in production premises. It also provided information that was vital for improving existing mite control measures and in implementing effective management strategies.

Acaridae↗