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PubMed1992

Dust from carpeted and smooth floors. V. Cat (Fel d I) and mite (Der p I and Der f I) allergen levels in school dust. Demonstration of the basophil histamine release induced by dust from classrooms.

Sixty dust samples from schools in Norway were analysed for major allergens from cat and mite after sampling with the regularly used vacuum cleaners for 5 days and with a new model vacuum cleaner for 10 days, respectively. The major feline allergen Felis domesticus allergen I (Fel d I) was detected in all the classrooms, with ranges from 12 to 16,840 ng/m2 floor area. The mean Fel d I concentration was about 11 times higher per unit area carpeted floors as compared with smooth floors after the 10 days sampling period. Mite allergens Dermatophagoides pteronyssinus allergen I (Der p I) and Dermatophagoides farinae allergen I (Der f I) were detected in very low concentrations, with ranges from < 1 ng to 104 ng/m2 floor area. These findings suggest that the school is a protective environment against mite infestation, while the prevalence of cat allergens in classrooms seems higher than previously assumed. Basophil histamine release was measured after provocation with 20 dust extracts from 10 different schools. In nine of the 10 schools examined, the basophil histamine release caused by challenge with carpet dust was higher than the corresponding release with smooth floor dust. The calculated floor areas in each school in which dust led to 15% histamine release were from 2 to 55 times larger for smooth floors compared with carpeted floors. These results emphasize previous findings regarding higher allergen concentrations in classrooms with carpeted floors.

Allergens↗
PubMed2004

Comparison between two thymol formulations in the control of Varroa destructor: effectiveness, persistence, and residues.

An apiary trial on the use of two acaricide formulations (gel-Apiguard and vermiculite and Api Life VAR) in the control of Varroa destructor (Anderson & Trueman) was conducted in summer 2001 in Sardinia (Italy). The main goals were 1) to determine their effectiveness against V. destructor, taking into account natural mite mortality in control hives; and simultaneously 2) to determine the persistence of both formulations and residues in honey and wax, by using a new extraction method. Both thymol formulations, after the treatments, reduced significantly the levels of mite infestations of adult bees and sealed brood, but their efficacy, expressed as percentage of mortality, was lower for both products (Api Life VAR 74.8 +/- 13.1 and 81.3 +/- 15.5, Apiguard 90.4 +/- 8.3 and 95.5 +/- 8.7 for sealed brood and adult bees, respectively) than the efficacy previously obtained with the same products in other experimental conditions. Moreover, a considerable colony-to-colony variability was recorded, and a significant negative effect of the thymol treatments on colony development was observed. During 2 wk of treatment, the bees removed nearly 95% of all the applied product (gel or vermiculite). Residues found in honey collected from the nest varied from 0.12 to 4.03 mg/kg for Api Life VAR and from 0.40 to 8.80 mg/kg for Apiguard. The residues were relatively higher in wax (Api Life VAR = 21.6 +/- 13.0; Apiguard = 147.7 +/- 188.9) than in honey, because thymol is a fat-soluble ingredient.

Animals↗
PubMed2004

Altered physiology in worker honey bees (Hymenoptera: Apidae) infested with the mite Varroa destructor (Acari: Varroidae): a factor in colony loss during overwintering?

The ectoparasitic mite Varroa destructor (Anderson & Trueman) is the most destructive pest of the honey bee, Apis mellifera L., in Europe and the United States. In temperate zones, the main losses of colonies from the mites occur during colony overwintering. To obtain a deeper knowledge of this phenomenon, we studied the mites' impact on the vitellogenin titer, the total protein stores in the hemolymph, the hemocyte characteristics, and the ecdysteroid titer of adult honey bees. These physiological characteristics are indicators of long-time survival and endocrine function, and we show that they change if bees have been infested by mites during the pupal stage. Compared with noninfested workers, adult bees infested as pupae do not fully develop physiological features typical of long-lived wintering bees. Management procedures designed to kill V. destructor in late autumn may thus fail to prevent losses of colonies because many of the adult bees are no longer able to survive until spring. Beekeepers in temperate climates should therefore combine late autumn management strategies with treatment protocols that keep the mite population at low levels before and during the period when the winter bees emerge.

Acari↗
PubMed2002

Randomized trial to prevent sensitization to mite allergens in toddlers and preschoolers by allergen reduction and education: one-year results.

OBJECTIVE: To evaluate the effectiveness of prevention measures against dust mite sensitization. DESIGN: European (England, Germany, Greece, Lithuania) multicenter prospective single-blind randomized control trial with a follow-up of 12 months. PARTICIPANTS: Toddlers and preschoolers, with at least 1 parent with atopic symptoms and sensitization, who initially were not sensitized to mite allergens. INTERVENTIONS: A combination of education and a simple preventive measure (mattress encasement) to reduce mite allergen exposure. SETTING: Community-based study. MAIN OUTCOME MEASURES: Sensitization to mite allergens (skin-prick test or specific immunoglobulin E). RESULTS: Of 636 children (mean age, 3.1 years) included in the study, 566 (89%) participated in the first-year follow-up. The incidence of sensitization to mite allergens was 10 (3%) of 330 in the intervention vs 20 (6.5%) of 306 in the control arm, including loss of follow-up (intention-to-treat principle). Allergic symptoms were more common in sensitized than in nonsensitized children and so was the prevalence of physician-diagnosed asthma, eczema, and food allergy. CONCLUSIONS: This simple, harmless, and inexpensive measure can be used in toddlers and preschoolers of parents with atopic disorders to reduce sensitization to mite allergens. With regard to clinical manifestations of atopy, follow-up studies are needed to determine the effectiveness of the intervention.

Allergens↗
PubMed2006

Cytologic findings in Demodex folliculitis: a case report and review of the literature.

Infectious folliculitis of the head and neck has various etiologies, including bacteria, viruses, fungi, and parasites. Accurate morphologic recognition of microorganisms in biopsy and cytologic specimens is paramount in facilitating appropriate therapy. We report a case of a 37-yr-old white male with Demodex folliculitis, who presented with an extensive and painful erythematous pustular skin lesion along the right face and scalp in a dermatome pattern clinically suggestive of Varicella zoster. Examination of scraped smears obtained from one of these pustules revealed numerous parasitic organisms having morphologic features typical of Demodex. Herein, we describe the patient's clinical presentation, discuss the cytologic findings of scrape smears, and briefly review the literature.

Adult↗
PubMed2005

Environmental scanning electron microscopy observation of the ultrastructure of Demodex.

In this study, numbers of Demodex of hair follicles and sebaceous glands were prepared and the ultrastructure (especially the mouthparts) of Demodex was observed firstly with environmental scanning electron microscopy (ESEM). The most suitable treatment methods and optimal environmental condition for observing the genus samples were found. The samples were washed with detergent and rinsed with distilled water, and then were taken to the specimen stage, on which there was carbon adhesive tape, using special tools. When the temperature was at 5 degrees C and chamber pressure at 5 mbar respectively, the surface of the samples could be fully imaged without covering water or dehydration. The sample surfaces were plump and clear without postmortem changes and charging artifacts. Detailed information about each part of Demodex was observed by ESEM, and clear three-dimensional images were recorded. The mouthparts of D. folliculorum were composed of a complex set of structures, which included a round oral opening, a sharp oral needle, and a special hypostome that looked like a longitudinal spindle in the central position. On the end segment of palpus, there were seven strong palpal claws located on each side of the mouthparts. D. folliculorum had special piercing mouthparts, while the mouthparts of D. brevis were a simpler structure. We could not observe the oral needle of D. brevis, and there were only five pairs of palpal claws on the end segment of palpus. The offensive organs of Demodex resulted in its pathogenic effects. After studying hundreds of Demodex, we identified both female and male species of D. folliculorum, but only females of D. brevis in our sample.

Animals↗
PubMed1996

Comparative analysis of the frequency of house dust mite specific and nonspecific Th1 and Th2 cells in skin lesions and peripheral blood of patients with atopic dermatitis.

Until recently it was believed that the T cell response of atopic dermatitis patients challenged with inhalant allergens originates almost exclusively and specifically from Th2 cells capable of secreting an abundance of interleukin (IL)-4 while producing no interferon (IFN)-gamma. To reevaluate this concept in a large cohort of atopic dermatitis patients we established 177 CD4+ T cell clones (45 of which showed specificity for house dust mite antigen) from the peripheral blood (n = 76), naturally occurring skin lesions (n = 40), and allergen-exposed skin (n = 61) of different patients. These clones were examined for their capacity to secrete IL-4 and IFN-gamma upon mitogenic stimulation. Moreover, 20 of these T cell clones were investigated for the synthesis of transcripts for IL-5, another Th cytokine. Our results indicate that the majority (52-100%) of allergen-specific T cells in both skin and blood of atopic individuals failed to exhibit a restricted cytokine secretion pattern and thus were classified as Th0 cells. House dust mite antigen specific T cells displaying a restricted secretion pattern (n = 16) were either of the Th1 or the Th2 type. Specific Th2 cells, however, were found almost exclusively in allergen patch test reactions, indicating that the Th2 differentiation pathway is seen preferentially in allergen-exposed skin. The cytokine secretion profile of T cell clones obtained from naturally occurring skin lesions showed similarity to those of patch test lesion, suggesting that the patch test represents a useful model to investigate the pathogenesis of atopic dermatitis.

Animals↗