Mean Number Of Mites Research Articles

Species Composition and Seasonal Abundance of Predatory Mites (Acari: Phytoseiidae) Inhabiting Aesculus hippocastanum (Sapindaceae)

Species of the family Phytoseiidae (Acari: Mesostigmata) inhabit a wide range of herbs, shrubs, and trees. Horse chestnut, Aesculus hippocastanum, is an important ornamental tree in Europe and, in addition to its importance for pollinators, it can serve as a host plant of these predatory mites. Little is, however, known about the factors affecting spatiotemporal variability in the density of phytoseiids on A. hippocastanum in an urban environment. We therefore assessed the species composition and the spatial and seasonal variability in the abundance of Phytoseiidae species in the city of České Budějovice, South Bohemia, Czech Republic. Compound-leaf samples were randomly collected from horse chestnut tree branches at eight sites, five times during the vegetation season in 2013. The mites were collected by washing technique and mounted on slides for identification. In total, 13,903 specimens of phytoseiid mites were found, and eight species were identified: Amblyseius andersoni, Euseius finlandicus, Kampimodromus aberrans, Neoseiulella tiliarum, Phytoseius macropilis, Paraseiulus talbii, Paraseiulus triporus, and Typhlodromus (Typhlodromus) pyri. The predominant species was E. finlandicus (96.25%). The mean number of mites per compound leaf was 2.53, 10.40, 23.54, 11.59, and 9.27 on the sampling dates in each month between May and September, respectively. The results further revealed that the mite abundance varied significantly among sampling sites and that it was negatively related to percentage of greenery area, intensity of greenery care, distance to water body, and density and age of horse chestnut trees, while it was positively related to air pollution index. The importance of leaf micromorphology for the attractiveness of A. hippocastanum to Phytoseiidae is discussed.

The correlation between Demodex infestation and meibomian gland dysfunction at different ages

BackgroundThis study aimed to explore the associations between Demodex infestation and the ocular surface characteristics of meibomian gland dysfunction (MGD) in different age groups, to further understand the effect of Demodex on MGD.MethodsA total of 202 consecutive MGD patients aged 18 to 70 years were randomly recruited. All patients were divided into two groups based on their age: young patients (18–40 years) and elderly patients (41–70 years). The main observations were the different relationship between Demodex infestation and ocular surface and meibomian gland (MG) parameters in two age groups. We also compared ocular surface and MG parameters between the young and the elderly groups. Demodex infestation was diagnosed based on expert consensus in China.ResultsOur results indicated significant differences among young Demodex-positive, suspicious-positive, and negative patients in MG dropout (P = 0.000), plugging of MG orifices (P = 0.000), lid margin abnormality (P = 0.000), and meibum quality (P = 0.000). In elderly patients, there were significant differences among the Demodex-positive, suspicious-positive, and negative groups in terms of ocular surface disease index (OSDI) (P = 0.037), fluorescein tear film break-up time (FBUT) (P = 0.002), corneal fluorescein staining (CFS) (P = 0.036), MG dropout (P = 0.000), plugging of MG orifices (P = 0.008), lid margin abnormality (P = 0.000), and MG expression (P = 0.037). The mean number of mites in elderly Demodex-positive patients (10.64 ± 7.50) was greater than that of in young patients (7.60 ± 4.71) (P = 0.014). MG dropout (P = 0.000), plugging of MG orifices (P = 0.006), lid margin abnormality (P = 0.000), MG expression(P = 0.001), and meibum quality (P = 0.032) were more severe in elderly Demodex-positive patients. Additionally, FBUT (P = 0.005) was lower and tear film lipid layer thickness (LLT) (P = 0.001) was higher in the elderly.ConclusionThe effect of Demodex infestation on the ocular surface and MG parameters of MGD was different in patients of different ages. It is necessary to pay more attention to the diagnosis and treatment of Demodex infestation in MGD.

Efficacy of fluralaner (Exzolt) for the treatment of natural Allopsoroptoides galli infestations in laying hens

Mite infestations in laying hens can cause losses to producers due to stress, reduced egg production and even death of birds. A new species of mite, Allopsoroptoides galli (A. galli), Analgoidea: Psoroptoididae, was recently identified in commercial laying farms in Brazil, causing damage due to its highly aggressive infestation that results in a sharp drop in egg production and culling. The present study evaluated the acaricidal action of a formulation containing fluralaner (Exzolt) against A. galli. Thirty-four laying hens naturally infested with A. galli were equally divided into a fluralaner-treated group and an untreated control group. The fluralaner-treated group received Exzolt in drinking water at a dose of 0.05 mL/kg body weight (equivalent to 0.5 mg fluralaner/kg body weight), twice, 7 d apart. Both groups were followed for 70 d evaluating the level of infestation by counting mites in skin scrapings and assessment of skin lesions. The average mite count of the treated group decreased significantly, dropping from 61.6 to 3.8 mites (D+7 to D+70). The efficacy progressively increased on subsequent days, reaching 98.8% on d +56 post-treatment and 96.9% on d +70. Recovery of skin lesions was observed after administration of Exzolt, showing a marked remission in the degree of lesions (2.5 on d −14 to 0.2 on d +70). The mean number of mites in the untreated control group ranged from 79.3 to 124.1 and the lesion score from 2.6 to 2.9, thus remaining stable throughout the study. The results obtained in the present study demonstrated that Exzolt administered at a dose of 0.05 mL of product/kg body weight (equivalent to 0.5 mg of fluralaner/kg body weight), twice at a 7-d interval, in drinking water was effective in the treatment of the mite Allopsoroptoides galli in naturally infested laying hens.

Comparison of goose down and woolen pillows in terms of house dust mites

This study was conducted to compare the goose down and the woolen pillows in terms of number of house dust mites per gram of dust. The study was conducted in Kars province, Turkey in September 2020. A total of 180 house dust samples were collected from 45 randomly selected houses in various districts of the city. The number of houses in which at least one sample was positive regarding mites was found to be 39 (86.66%). Overall, 137 (76.11%) of dust samples were mite positive. This rate was 87.77% in dust samples of woolen and 64.44% in dust samples of goose down pillows. The number of mites/g dust varied between 15 and 625 in mite-positive woolen pillows, 10 and 420 in mite-positive goose down pillows. Mean number of mites per g of dust was 127.67 in woolen pillows and 79.39 in goose down pillows. A statistically significant difference was found between woolen and goose down pillows in terms of the number of mites per gram of dust (P<0.05). A total of 1,362 mite specimens were isolated from the dust samples. As a result of the identification of isolated specimens; a total of 16 species belong to 10 genera and 6 families were determined. Of these; Dermatophagoides pteronyssinus (Trouessart, 1897) (65.85%), Lepidoglyphus destructor (Schrank) (9.25%) and Acarus siro Linnaeus (6.16%) were the most dominant species in terms of number of specimens.

Seasonal incidence of brinjal shoot and fruit borer and red spider mite with their natural enemies’ fauna in brinjal crop ecosystem

An experiment was conducted on seasonal incidence of brinjal shoot and fruit borer, Leucinodes orbonalis (BSFB) and red spider mite, Tetranychus macfarlanei and their natural enemies fauna in brinjal ecosystem at Chatha experimental Farm, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, India during 2014 and 2015. There were fourteen insect pests and fifteen natural enemies fauna were recorded during the two years of experimentation. Out of fourteen, 04 major insect pests like BSFB, hadda beetle, white flies, jassid; 01 non-insect pest like red spider mite; 09 minor insects along with twelve predators and three parasitoids were recorded during both the years. The seasonal incidence of peak larval population was observed during 24th and 30th standard weeks recording a maximum of 14.33 and 14.00 weekly mean larvae/15 plants, respectively during 2014 and 2015. There were two clear peaks of adult trap catches of BSFB population noticed during 22nd standard week and in 30th standard week in case of wota traps. The maximum incidence of red spider mites were recorded during 25th and 26th standard weeks recording a maximum (51.81 and 36.02) mean numbers of mites per 4 cm2 on brinjal during both the years of study.

High prevalence and intensity of infestation of Eutrombicula alfreddugesi (Acarina: Trombiculidae) on Tropidurus torquatus (Squamata, Tropiduridae): effects of body size and on body condition across ten populations along the Brazilian coast

We investigated the infestation of Eutrombicula alfreddugesi mites on Tropidurus torquatus lizards across ten coastal populations in Brazil to evaluate variations among localities and relationships with intrinsic features of hosts (body size and body condition). For each population, we calculated the prevalence of infestation and the mean number of mites per host (mean intensity of infestation). Lizards from all populations were infested by mites, with prevalence ranging from 95.6 to 100%. Mean intensities of infestation also were always high, ranging from 55.3 ± 88.8 to 280.9 ± 208.2 mites per lizard. The lizard body regions most intensely used as microhabitat by mites were the axillae and neck (which bear “mite pockets” in T. torquatus). In most populations, the number of mites tended to increase with the body size of hosts. The body condition of hosts and the intensity of infestation were positively correlated, considering the total sample (i.e. lizards of all populations pooled). The main microhabitats (i.e., body regions) used by E. alfreddugesi on T. torquatus represented total intensities of infestation, suggesting that counting mites on these body regions provide a useful index to estimate the overall intensity of infestation. Lizards are suitable and predictable resources for parasitic mites, which take advantage of ecological and morphological features of host individuals and species, with large body sizes, imbricated and keeled scales, and presence of skin folds and mite pockets favoring occupation and high intensities of infestation by mites.

Response to selected ecological parameters by Leptus hringuri Haitlinger, 2000 larvae (Trombidiformes: Erythraeidae) parasitizing treehoppers (Hemiptera: Membracidae) from Bolivia on two host-plant species

ABSTRACTLarvae of Leptus hringuri parasitizing families (adult female + offspring) of the treehopper Alchisme grossa on two host-plants, Brugmansia suaveolens (BS) and Solanum ursinum (SU), were studied. The effect of microenvironmental abiotic conditions (luminosity, temperature and relative humidity) and biotic conditions (distance from the soil to a treehopper host and host-plant phenological stage) on this tritrophic interaction was examined. Overall, the results suggest i) intensity of mite infestation (mean number of mites per infested female or family) of treehoppers (insect hosts) was twice on SU than on BS, ii) a preference of L. hringuri larvae for places with more luminosity (on both host-plants) and relative humidity (on SU), iii) a negative correlation between larval infestation and distance of the host colony to the ground, and iv) that larvae of L. hringuri could detect cues (i.e. chemical) emitted by their insect hosts or the host-plant of the insect host. Results indicate that luminosity, humidity and distance to the ground of the insect-host microenvironment affect both parasitization and prevalence of Leptus larvae mites; however, further research will be needed to understand the ecological mechanisms and consequences of these interactions and to test the hypotheses proposed herein under a chemical ecology perspective.

Prevalence of Demodex spp. in students and employees of the Pomeranian Medical University in Szczecin

Abstract Introduction: Demodex folliculorum and Demodex brevis are mites living in the hair follicles and sebaceous glands of humans, with infestation usually being asymptomatic. In the present study the prevalence and number of mites, together with influencing factors of Demodex infestation, were investigated in students and personnel of the Pomeranian Medical University in Szczecin in Poland (PUM). The prevalence of 2 Demodex species, Demodex folliculorum and Demodex brevis, was compared in epilated eyelashes and skin scrapings derived from healthy volunteers. Materials and methods: The study was conducted on 217 healthy volunteers – females and males. The study group consisted of 114 students and 103 employees of PUM. From each study participant, 2–3 eyelashes from each lid were epilated. From 99 volunteers, skin scrapings and/or secretions from sebaceous glands were also obtained. Demodicosis was diagnosed when Demodex eggs, larvae or adult mites were identified under microscopic examination. Results: The infestation rate of Demodex (in epilated eyelashes and skin) among the 217 volunteers was 21%. Prevalence of hair follicle mites among personnel and students were 28% and 14% respectively. The mean number of mites among the 217 patients was 2.52 ±2.48 (3.16 ±2.9 in PUM personnel and 1.46 ±0.83 in students). The infestation rate increased with age (p = 0.0005). Demodex folliculorum infested 78% (p = 0.005) of the participants and 87.5% of epilated eyelashes (p = 0.000001). Demodex brevis was more frequent on the skin (67%; p = 0.00001). Hair follicle mites were detected more often in epilated eyelashes originating from the lower lid (p = 0.000001). Moreover, a weak correlation between the presence of selected symptoms (blepharedema, conjunctivitis, burning and itching of eyelids) and Demodex infestation was observed. There was no statistically significant association between Demodex infestation and an influencing factor: work using a microscope (p = 0.92).

The Importance of Demodex Mites (Acari: Demodicidae) in Patients With Sickle Cell Anemia.

Although demodicosis caused by Demodex folliculorum and Demodex brevis is widely seen throughout the world, the pathogenic mechanisms are not fully known. To the best of our knowledge, the effect of Demodex mites in patients with sickle cell anemia (SCA) is not known. SCA is a genetic disease characterized by abnormal hemoglobin production and suppression of the immune system. The aim of this study was to determine the prevalence and Demodex density in SCA patients and to compare with healthy subjects. The study included 70 patients diagnosed with SCA and control group of 50 healthy individuals. Samples were taken from cheeks, forehead, nose, and chin and were examined microscopically. Infestation of ≥5 mites/cm2 was accepted as positive in the diagnosis. Demodex mite positivity was determined in 20 (28.6%) patients and none in subjects of the control group. In the SCA group, the mean number of mites was 26.10/cm2. A statistically significant correlation was found between Demodex mite positivity and the number of SCA symptom attacks experienced by the patients within the last 1 yr (P ≤ 0.001). No significant relationship was determined between Demodex mite positivity and age or gender (P = 0.56 and P = 0.11, respectively). Demodex mites are seen more often in SCA patients who suffer from a compromised immune system, and the presence of Demodex mites could be a risk factor in the appearance of SCA symptom attacks.

Demodex mites in acne rosacea: reflectance confocal microscopic study.

Demodex mite density is emphasised in the aetiopathogenesis of acne rosacea. Reflectance confocal microscopy (RCM) has been shown to be a good method for determining demodex mite density. The objective was to determine demodex mite density using RCM in acne rosacea patients and compare them with controls. In all, 30 papulopustular rosacea (PPR) and 30 erythematotelangiectatic rosacea (ETR) totally 60 acne rosacea patients and 40 controls, were enrolled in the study. The right cheek was selected for imaging and RCM was used for scanning. Ten images of 1000 × 1000 μm (total 10 mm2 ) area were scanned from adjacent areas. The numbers of follicles, infested follicles and mites were counted. The mean numbers of mites per follicle and infested follicles were calculated and compared in the patients and control groups. The mean number of mites was 44.30 ± 23.22 in PPR, 14.57 ± 15.86 in ETR and 3.55 ± 6.48 in the control group (P < 0.001). The mean number of mites per follicle was 1.77 ± 0.90 in PPR, 0.57 ± 0.63 in ETR and 0.13 ± 0.23 in the control group (P < 0.001). The cut-off for the mean number of mites for determining mite infestation was 0.17 and above. Demodex mite density was markedly increased in both ETR and PPR patients. It is believed that the presence of demodex mites plays an important role in rosacea aetiopathogenesis. Demodex mite treatment may reduce the severity of the disease and slow its progressive nature.

Variability in Population Density of House Dust Mites of Bitlis and Muş, Turkey.

This study was conducted to investigate the relationship between the number of house dust mites/g dust and different physical and environmental variables. A total of 1,040 house dust samples were collected from houses in Bitlis and Muş Provinces, Turkey, between May 2010 and February 2012. Overall, 751 (72.2%) of dust samples were mite positive. The number of mites/g dust varied between 20 and 1,840 in mite-positive houses. A significant correlation was detected between mean number of mites and altitude of houses, frequency of monthly vacuum cleaning, number of individuals in the household, and relative humidity. No association was found between the number of mites and temperature, type of heating, existence of allergic diseases, age and structure of houses. A maximum number of mites were detected in summer and a minimum number was detected in autumn.

House Dust Mites in Erzincan Province.

We aimed to determine the species of the house dust mites seen in Erzincan, the number of mites per gram of dust in the houses, and the relationship between temperature and the number of mite specimens. For this purpose, 54 dust samples collected from 18 houses located in different districts of Erzincan province between November 2013 and January 2014. These samples were examined by a lactic acid precipitation method. Of the houses in which the dust samples were collected, 94.44% were found to be positive in terms of mites. A total of 844 mite specimens were isolated from the dust samples, and the mean number of mites per gram of dust was found to be 18.34. The most common species was found to be Acarus siro (55.55%) and was followed by Dermatophagoides pteronyssinus (50.00%), Tyrophagus putrescentiae (22.22%), Histiostoma sp. (22.22%), Lepidoglyphus destructor (16.66%), T. perniciosus(11.11%), Euroglyphus maynei (11.11%), Glycyphagus privatus (11.11%), Cheyletus sp. (11.11%), Tarsonemus sp. (11.11%), and Tetranychus sp. (11.11%). Mite-holding rate of the houses in Erzincan province was found to be 94.44%. The mean number of mites per gram of dust was found to be 18.34. The most common mite species was A. siro, which was followed by D. pteronyssinus.

Reflectance confocal microscopy for monitoring the density of Demodex mites in patients with rosacea before and after treatment.

Demodex mites seem to serve as a pathogenic trigger in many Demodex-associated diseases such as rosacea. In facial skin of patients with rosacea significantly higher numbers of Demodex mites have been shown compared with healthy controls. Reflectance confocal microscopy (RCM) allows the detection and quantification of Demodex mites in vivo noninvasively. It is hypothesized that a reduction of Demodex mites under rosacea therapy can be monitored by RCM. To use RCM to monitor the density of Demodex mites in patients with rosacea before and after treatment. In 25 patients with facial rosacea RCM was performed before and after therapy. Mosaics of 5 × 5 mm(2) and 8 × 8 mm(2) were scanned, and the total numbers of mites per follicle and per area were counted, along with the number of follicles per area. In all patients Demodex folliculorum could be detected and quantified using RCM. RCM showed significant differences pre- and post-treatment (P = 0.0053 for 5 × 5 mm(2) and P < 0.001 for 8 × 8 mm(2)). The mean numbers of mites per follicle were 0.63 (range 0.16-2.28) per 8 × 8 mm(2) area and 0.70 (range 0.11-2.20) per 5 × 5 mm(2) area before treatment, and 0.41 (range 0.074-1.75) and 0.51 (range 0.094-1.70), respectively, after treatment. The corresponding mean numbers of mites were 155 (range 45-446) and 86.2 (range 12-286), respectively, before treatment and 96.2 (range 18-363) and 58.5 (range 12-230), respectively, after treatment. By RCM, a reduction in the density of Demodex mites in facial skin of patients with rosacea under therapy, correlating to clinical improvement, can be quantified and monitored noninvasively. Possible reasons for this therapeutic effect are discussed.

Dynamics of house dust mite transfer in modern clothing fabrics

BackgroundClothing is largely presumed as being the mechanism by which house dust mites are distributed among locations in homes, yet little research to date has investigated the capacity with which various clothing fabric types serve as vectors for their accumulation and dispersal. Although previous research has indicated that car seats provide a habitat for mite populations, dynamics involved in the transfer of mites to clothing via car seat material is still unknown. ObjectiveTo investigate the dynamics involved in the transfer of house dust mites from car seat material to modern clothing fabrics. MethodsA total of 480 samples of car seat material were seeded with mites and subjected to contact with plain woven cotton, denim, and fleece. Contact forces equivalent to the mass of a typical adult and child were administered for different durations of contact. ResultsMean transfer efficiencies of mites from car seat material to receiving clothing fabrics ranged from 7.2% to 19.1%. Fabric type, mite condition (live or dead), and the force applied all revealed a significant effect (P < .001 for each variable) on the transfer efficiency of house dust mites from seeded material to receiving fabrics, whereas duration of contact revealed no effect (P = .20). In particular, mean numbers of mites transferred to fleece (compared with denim and plain woven cotton) were greater for each treatment. ConclusionThese findings indicate that clothing type can have important implications for the colonization of other biotopes by house dust mites, with potential for affecting an individuals' personal exposure to dust mite allergens.

Noninvasivein vivodetection and quantification ofDemodexmites by confocal laser scanning microscopy

In many Demodex-associated skin diseases Demodex mites are present in abundance and seem to be at least partially pathogenic. So far all diagnostic approaches such as scraping or standardized superficial skin biopsy are (semi-)invasive and may cause discomfort to the patient. To see whether confocal laser scanning microscopy (CLSM) - a noninvasive method for the visualization of superficial skin layers - is able to detect and quantify D. folliculorum in facial skin of patients with rosacea. Twenty-five patients (34-72 years of age) with facial rosacea and 25 age- and sex-matched normal controls were examined by CLSM. Mosaics of 8 × 8 mm and 5 × 5 mm were created by scanning horizontal layers of lesional skin and quantification of mites per follicle and per area as well as follicles per area was performed. In all patients D. folliculorum could be detected by CLSM and presented as roundish or lengthy cone-shaped structures. CLSM allowed the quantification of Demodex mites and revealed significant differences (P < 0·0001): the mean number of mites was 165·4 per 8 × 8 mm area and 94·2 per 5 × 5 mm area in the patients compared with 34·7 and 22·4, respectively, in the controls. The corresponding mean number of mites per follicle was 0·7 and 0·8, respectively, in the patients and 0·1 and 0·2, respectively, in the controls. With the help of CLSM it is possible to detect, image and quantify Demodex mites noninvasively in facial skin of patients with rosacea.

Mite communities (Acari, Mesostigmata) associated with Ips typographus (Coleoptera, Scolytidae) in managed and natural Norway spruce stands in Central Europe

Abstract Previous studies have suggested that forest management practices can influence bark beetle populations as well as those of some associated insects. However, the impact on bark beetle-associated mites, which occur in bark beetle galleries in large numbers, have not yet been studied. The objective of this study was to compare mesostigmatid mite communities associated with the Norway spruce pest Ips typographus in managed and natural forest stands separated by spruce-free belt. The study sites were located in Białowieża National Park (NE Poland) as well as in the Izery Mountains (Szklarska Poręba Forest District — SW Poland), which were destroyed in 1981–1987 by an ecological disaster. In total, 30 Borregard pipe traps containing the commercial attractant Ipsodor W (Chemipan, Poland) were set up at each study site and collected in August 2010. In total, 7214 bark beetles and 1804 mites were collected which were classified into 16 species. We observed differences in the total abundance of mites as well as the total number of recorded mite species. The communities were quite similar, and were generally dominated by populations of Trichouropoda polytricha, Dendrolaelaps quadrisetus and Uroobovella ipidis. The Shannon and Evenness indexes as well as the mean number of mites per sample were not significantly different between forests.

Demodex folliculorum: Requirements for Understanding Its Role in Human Skin Disease

Correspondence: Michael S. Christensen, Springhouse Skin Research, Inc., 215 Springhouse Lane, Merion Station, Pennsylvania 19066, USA. E-mail: mikesenior@verizon.net was then pressed against the medial cheek, causing the glue to spread to a thin film the width of the slide (1 inch) and approximately half its length (1.5 inch). The slide was left in place for 5 minutes while the cyanoacrylate hardened as it polymerized. Before removal, an outline of the slide was drawn with a Sharpie permanent marker, leaving a demarcated area on which a second cyanoacrylate-coated slide was applied. Two sequential surface biopsy samples were thus obtained, taken from precisely the same site, a procedure that caused minimal discomfort and erythema. Slides were placed face up on the stage of a stereomicroscope for quantitative assessment of horny casts and determination of mite density per square centimeter. A second biopsy is shown in Supplementary Figure 1. To quantify mite densities, with the slide in place the microscope stage was moved under the objective lens to generate five distinct representative fields. The casts in each were counted separately, and a mean of the five values was used to calculate casts per square centimeter. To liberate the mites from the casts, a drop of olive oil was placed on the slide, sufficient to cover the entire sample. Casts (a total of 20, randomly selected) were then disrupted individually with a fine needle. As each cast was disrupted, the number of mites released was immediately counted while the mites swam freely in the olive oil medium (Supplementary Figure 2). Mites remained mobile in the olive oil for nearly 3 hours, in contrast to less than 2 hours in mineral oil, before becoming motionless and more difficult to distinguish from cellular debris. Even when large numbers of casts were found on a biopsy, not all casts contained mites, so we determined two factors after counting: the percentage of casts infested and the mean number of mites per infested cast. Using these two factors and the number of casts per square centimeter, we calculated the number of mites per square centimeter The data and text commentary herein were drawn posthumously from labor atory notebooks and writings found in Dr. Kligman’s study and bedroom. Comments in brackets were added by Barbara A. Gilchrest (Department of Dermatology, Boston University School of Medicine) and James J. Leyden (Department of Dermatology, University of Pennsylvania School of Medicine). Demodex folliculorum was first described independently by two investigators nearly 170 years ago. Human beings are the sole host for this mite (Supplementary Figure 1 online), which resides exclusively in sebaceous follicles and has been repeatedly but inconclusively implicated in rosacea by more than 1,000 peer-reviewed papers, approximately half of them published since 1990. Sometimes visible within follicles in routine cross-sectional biopsy sections, Demodex is more reliably detected in “skin surface biopsies,” a technique first employed by Marks and Dawber (1971) and modified by Mills and Kligman (1983). The purpose of this investigation is to further refine the technique to make it more accurate, reproducible, and quantitative— characteristics necessary for implicating the mites in skin disease. [One of Kligman’s characteristics was to periodically start over and assume everything previously said or published was probably wrong, even if it was he who had said or published it. At times in the past he had dismissed the possibility that Demodex has a role in skin disease, but at the end of the trail he reversed his position and determined to seek data in support of the possibility. Thus, with his longtime collaborator, Mike Christensen, Kligman embarked on a bottom-up re-exploration of whether Demodex plays a role in skin disease. True to his lifelong approach, Kligman decided to begin by improving, if possible, the technique for quantifying Demodex.This methodology is described online.]

Mite numbers and allergens in house dust from school environments in Kanagawa Prefecture

Prevalence of house dust mites and allergens was evaluated in ten kindergartens/elementary schools in Kanagawa Prefecture during school suspension periods in March and August, 2006. The mites on the surface of the infirmary bedding and classroom carpet (50cm×50cm) were captured with an adhesive lint roller. Thereafter the numbers of mites on the adhesive papers were counted under a stereomicroscope. House dust was also collected with a vacuum cleaner, and the quantities of house dust mite allergens (Der f1/Der p1/Der 2) measured by ELISA. Mean numbers of mites obtained from bedding-March and August, carpet-March and August were 23, 97, 13, 173/m^2, respectively. Mean allergen quantities of Der 1 were 933, 3, 168, 1, 900, 3, 457ng/m^2, and Der 2 were 65, 208, 118, 284 ng/m2. The quantities of Der f1 were much higher than Der p1 in the total Der 1. Consequently, 100 house dust mites (Dermatophagoides spp.) per square meter were equivalent to 3, 700 and 1, 800ng (Der 1)/m^2 for bedding and carpet.

Strip cropping wheat and alfalfa to improve the biological control of the wheat aphid Macrosiphum avenae by the mite Allothrombium ovatum

Strip cropping of wheat ( Triticum aestivum ) and alfalfa ( Medicago sativa ) as a mechanism for improving the effectiveness of biological control of the wheat aphid ( Macrosiphum avenae ) by the mite ( Allothrombium ovatum ) was studied from 2002 to 2004 in Luancheng County, Hebei Province, China. Results showed that the strip cropping of wheat and alfalfa significantly increased the egg and larval densities of A. ovatum and the percentage of M. avenae parasitized by larval mites compared with the monoculture of wheat. The mean number of mites per parasitized aphid was also significantly higher in strip cropping than in wheat monoculture. The percentage of parasitized aphids was shown as a negative and logarithmical function of the mean population growth rate of wheat aphid, however such a relationship was statistically significant only in the strip cropping plots. The higher incidence of parasitism on alate than on apterous aphids indicated that parasitism of alate aphids by A. ovatum play an important role in facilitating A. ovatum dispersal and limiting wheat aphid population increase.

CHERRY, CONTROL OF TWO SPOTTED SPIDER MITE AND EUROPEAN RED MITE, 2003

This study was established to screen new materials and rates of miticides for control of TSSM and ERM in tart cherries. The trial was conducted at the Northwest Michigan Horticulture Research Station in Traverse City, MI. Three-tree plots were established in a mature block of Montmorency tart cherry trees, and treatments then assigned in a RCB design with four replications. The test materials were applied at threshold on 7 Aug with an FMC 1229 airblast sprayer calibrated to deliver 60 gpa. Random samples were collected from four areas of the orchard on a weekly basis to monitor TSSM populations for action threshold levels of seven to ten motiles per leaf. A pre-application count of TSSM and ERM motiles was conducted on 6 Aug, and subsequent post-application evaluations were made on 11 Aug (4 DAT), 18 Aug (11 DAT), 25 Aug (18 DAT), 2 Sep (26 DAT), and 8 Sep (32 DAT). On each date, 50 randomly selected leaves were picked from the middle tree of each replicate, brought back to the lab, and passed through a mite-brushing machine. Motile forms of TSSM and ERM were then counted with the aid of a stereo microscope. Since ERM populations did not develop in this trial, no data are reported. All mite data are reported as the mean number of mites per leaf and were analyzed using ANOVA and means separation by LSD at P = 0.05.