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PubMed1999

Linkage of house dust mite allergy with the HLA region.

BACKGROUND: Atopy is a multifactorial disease, the pathogenesis of which is influenced by both genetic and environmental conditions. Genes in the HLA region have been involved in the control of the IgE response. OBJECTIVE: In order to investigate whether allergy to house dust mite is associated with HLA in our population, we performed sib-pair analysis in 18 families and a case/control study of 161 non-related individuals. METHODS: Levels of total and specific IgE were determined, skin-prick tests were carried out and clinical history was reviewed for every subject in the study. HLA class II typing was performed by the polymerase chain reaction with sequence specific primers. RESULTS: We observed a significant difference from expected values in haplotypes shared by affected sibs; however, the case/control study did not reveal any association with any particular allele. CONCLUSION: These results suggest that any particular HLA-DRB1/DQA1/DQB1 allele is responsible for the development of allergy to house dust mite in the Spanish population. Some other locus in or close to the HLA region might be involved, e.g., the tumour necrosis factor gene, a possibility that would explain the significant difference from expected values in the segregation of HLA haplotypes.

Adolescent↗
PubMed1999

New occupational allergen in citrus farmers: citrus red mite (Panonychus citri).

BACKGROUND: There have been several reports of occupational allergy to spider mites (Tetranychidae), but no published report has described citrus red mite (CRM, Panonychus citri)-induced occupational asthma confirmed by specific bronchial challenge. OBJECTIVE: The purpose of this study was to evaluate clinical and immunologic characteristics of CRM-induced occupational asthma. METHODS AND RESULTS: We encountered 16 cases of CRM-induced occupational asthma among farmers cultivating citrus fruits. Asthmatic attacks corresponded closely with their work on citrus farms. The mean duration of the latent period was 12.9 (range 7 to 20) years. During their first visit to our clinic, nine patients with FEV1 lower than 70% of predictive value showed reversible airway obstruction after inhalation of bronchodilator, and seven with FEV1 greater than 70% of predictive value showed airway hyperresponsiveness to methacholine. Fifteen of the 16 also complained of recurrent nasal symptoms, which had developed at an earlier time than the asthmatic symptoms. They showed strong positive reactions to CRM extract on skin prick test (A/H ratio > or = 1.0) and had high serum specific IgE antibody against CRM which was detected by ELISA. Skin prick test with common inhalant allergens revealed that 10 had an isolated positive response to CRM with negative results to common inhalant allergens in their environment. The ELISA inhibition tests with CRM demonstrated significant inhibitions by CRM in a dose-dependent manner, while minimal inhibitions were noted by D. pteronyssinus and mugwort allergens. CONCLUSION: These findings suggest that CRM could induce IgE-mediated bronchoconstriction in exposed workers on citrus farm.

Adult↗
PubMed1999

Comparison of the efficacy of subcutaneous and sublingual immunotherapy in mite-sensitive patients with rhinitis and asthma--a placebo controlled study.

BACKGROUND: The efficacy of therapy with sublingual allergen extracts is unproven. OBJECTIVE: To evaluate the clinical and immunologic outcome of sublingual immunotherapy and to compare the results with subcutaneous immunotherapy and placebo in 36 patients with rhinitis and asthma due to mite allergy. METHOD: Thirty-six patients with rhinitis and asthma due to mite allergy were randomly divided into three groups in order to receive subcutaneous injections with allergenic extracts, sublingual drops with solutions of purified standardized allergen preparations, or sublingual placebo for a period of 1 year. Assessment of clinical and immunologic efficacy included symptom and medication scores, methacholine provocation tests, skin prick tests, and specific IgE and IgG4 antibody concentrations. RESULTS: Subcutaneous immunotherapy for both rhinitis and asthma was clinically effective. Patients treated with sublingual immunotherapy had decreased rhinitis symptoms (P < .01) but no change in asthma scores. Medication scores significantly decreased in both actively treated groups (P < .01) at the first year compared with baseline. When skin prick tests were evaluated, the subcutaneously treated group had a significant decrease in the wheal diameter of D. pteronyssinus (P < .01), D. farinae (P < .05), and histamine (P < .05) while other two groups showed no difference. There was no significant change in methacholine PC20 values in all groups at the end of the first year when compared with baseline. No change in D. pteronyssinus and D. farinae specific IgE levels were observed; however, specific IgG4 concentrations were significantly higher than baseline both in sublingual and subcutaneous immunotherapy groups (P < .05) after 1 year immunotherapy. No significant difference was obtained in any of these parameters in the placebo group. CONCLUSION: Sublingual immunotherapy may be effective in patients with allergic rhinitis. Further, we believe it is a potential therapy for allergic asthmatic patients. The clinical usefulness of this form of immunotherapy (when administered to larger study groups for a longer time) and the mechanisms underlying its immunologic effect deserve additional studies.

Administration, Cutaneous↗
PubMed1996

Cross-allergenicity of the house dust mites Euroglyphus maynei and Blomia tropicalis.

BACKGROUND: The domestic mites Euroglyphus maynei and Blomia tropicalis frequently co-inhabit homes in subtropical/tropical regions around the world. Both species are the source of substances that cause allergic reactions in patients. OBJECTIVE: The purpose of this study was to examine the immunologic cross-reactivity between E. maynei and B. tropicalis. METHODS: Sera of 19 mite-sensitive patients who were skin test positive to B. tropicalis and/or RAST positive to E. maynei were used to probe immunoblots or crossed radioimmunoelectrophoresis (CRIE) gels. RESULTS: Western blotting showed that individual sera had IgE that bound to 0 to 17 and 2 to 15 proteins in E. maynei and B. tropicalis extracts, respectively. Corresponding IgE-binding proteins of 105, 75, 57, 18, and 14 kD were detected in both E. maynei and B. tropicalis extracts. The majority of IgE-binding proteins did not show corresponding bands in both extracts. Heterologous CRIE showed IgE binding to six of the nine E. maynei antigens precipitated by anti-B. tropicalis serum with individual sera recognizing 0 to 4 of the six allergens. In the reciprocal reaction, 10 of the 12 proteins of B. tropicalis that were precipitated by anti-E. maynei serum bound IgE with individual sera binding to 0 to 5 proteins. CONCLUSION: This study indicated that E. maynei and B. tropicalis are the source of both species-specific and cross-reactive allergens, but most allergens in each extract were species-specific.

Adult↗
PubMed1996

Seasonal changes in mite allergen (Der I and Der II) concentrations in Japanese homes.

BACKGROUND: There has been no report on seasonal changes in Der II allergen in floor and bedding dust. OBJECTIVE: The purpose of this study was to examine the extent of seasonal changes in Der I and Der II allergens in the floor and bedding dust found in houses. METHODS: We measured the absolute concentrations of mite allergens in dust collected monthly for 1 year from both the floors and bedding of eight houses in Tokyo. Dust samples were obtained from eight families without regard to their allergy histories. The concentrations of the Der p I, Der f I, and Der II allergens were measured by fluorometric sandwich ELISA. RESULTS: We found seasonal changes in the concentrations of these mite allergens. The highest concentrations of Der I (Der p I plus Der f I) and Der II (Der p II plus Der f II) were present from August to October, and the lowest ones from March to April. In floor dust, the mean highest concentrations of Der I and Der II (35.0 and 20.2 microgram of fine dust) were sevenfold and fivefold respectively, times the mean lowest concentrations. In bedding dust, the mean highest concentrations of Der I and Der II (51.3 and 29.6 microgram/g of fine dust) each were fourfold times the mean lowest concentrations. CONCLUSIONS: The patterns of seasonal changes in Der II in floor and bedding dust were similar to those of Der I.

Allergens↗
PubMed2001

Effect of roxithromycin on T lymphocyte proliferation and cytokine production elicited by mite antigen.

Clinical evidence suggests that roxithromycin (RXM) may be an effective additional therapy for bronchial asthma. However, how it interferes with allergic responses is unclear. To investigate the mechanisms of action of RXM, lymphocyte transformation and interferon (IFN)-gamma, interleukin (IL)-4 and IL-5 synthesis associated with Dermatophagoides farinae (Df), mite antigen in patients with bronchial asthma were evaluated in vitro in the presence of RXM. T cell proliferation in Df antigen-stimulated patients' lymphocytes was suppressed by 50-100 microg/ml of RXM. Production of IL-4 and IL-5 was similarly decreased by 1-10 microg/ml RXM, whereas, IFN-gamma production, which was reduced by Df-stimulation alone, was increased by 50 microg/ml RXM. Our results suggest that skewed cytokine profiles of patients with mite antigen-induced bronchial asthma may be corrected with RXM, which may mimic those of patients in remission, who are tolerant of Df antigen.

Adolescent↗
PubMed1976

Laboratory infections of Scheloribates spp. (oribatid mites) with Moniezia expansa and M. benedeni.

Scheloribates laevigatus (Koch, 1836) and Scheloribates fimbriatus (Thor, 1930), predominant species of oribatids in soil of Bombay region, were experimentally exposed to infection by uniform suspensions of eggs of Moniezia expansa and M. benedeni. The percentages of mites infected and the average number of cysticercoids developing were observed in 12 sets of experiments. The mites were more readily infected with eggs of M. expansa than with those of M. benedeni. S. laevigatus were infected with M. expansa and less with M. benedeni than S. fimbriatus.

Animals↗
PubMed1988

The release of histamine from nasal polyp tissue and peripheral blood when challenged with antihuman IgE, house dust mite extract and mixed grass pollen extract and compared with positive skin tests.

Nasal polyps are a condition of uncertain aetiology but are associated with diseases of the lower respiratory tract, in particular, asthma and cystic fibrosis. Asthma may be mediated by mast cell reactions and the commonest allergen to degranulate mast cells is house dust mite. Mast cells have been shown to be degranulated in nasal polyps. This study looks at thirty-six patients who had nasal polypectomy and of whom fourteen were asthmatic to see if histamine was released from polyp tissue and peripheral blood when they were challenged with antihuman IgE and extracts of house dust mite and mixed grass pollens. These results were compared with skin tests to these allergens. A release of above 15 per cent of the total histamine was considered positive. Eight patients released histamine from polyp tissue but only three patients released histamine with both anti IgE and allergen extracts. The release from blood compared well with positive skin tests (p greater than 0.05 corrected chi square). Although allergy may cause mast cell degranulation in polyp tissue, this study suggests that it is unlikely to be a common cause of nasal polyps.

Animals↗
PubMed2001

Modifications of the cuticular hydrocarbon profile of Apis mellifera worker bees in the presence of the ectoparasitic mite Varroa jacobsoni in brood cells.

Varroa jacobsoni is an ectoparasite of Apis mellifera which invades brood cells, on 8-day-old larvae several hours before cell capping. Reproduction of the parasite takes place in the capped brood cells during the nymphose of the bee. Cuticular hydrocarbons of unparasitized bees and of bees parasitized by Varroa jacobsoni were extracted and analysed by gas chromatography (GC) coupled with mass spectrometry (GC-MS). Three developmental stages of worker honey bees were studied: larvae, pupae and emergent adults. The comparison between unparasitized and parasitized hosts was performed with Principal Components Analysis coupled with a multivariate variance analysis. The cuticular hydrocarbon profiles of honey bees were qualitatively similar, for the 3 developmental stages and regardless of the presence of Varroa in the cells. Nevertheless, comparison of the relative proportions of hydrocarbons showed that the cuticular profiles of pupae and emergent adults parasitized by 1 mite and of larvae parasitized by 2 mites were significantly different from the corresponding unparasitized individuals. Such modifications could be regarded (i) as a cause of the multi-infestation in larvae during invasion of brood and (ii) as a consequence of stress and/or removal of proteins contained in the haemolymph of the host during its development.

Animals↗
PubMed2005

Life stage specific impact of dimethoate on the predatory mite Hypoaspis aculeifer canestrini (Gamasida: Laelapidae).

Toxicants may affect juveniles more than adults because of physiological and behavioral aspects. When developing toxicity tests, this issue is often not addressed, and the most sensitive end point may be ignored. The topic was raised by a European working group aiming to develop a standard toxicity test with the predatory mite, Hypoaspis (Geolaelaps) aculeifer Canestrini, as this species was included in the EU Guidance documentfortesting of pesticides. To assess whether the juvenile life stages are the most susceptible, we examined the acute toxicity of dimethoate on larvae, protonymphs, deutonymphs, males, and females of H. aculeifer. The mites were exposed to 0, 2, 4, and 6 mg dimethoate kg(-1) for 7 days in an OECD artificial soil (5% organic matter). Total juvenile biomass, reproduction, mortality, and population growth rate (pgr) lambda were assessed at the end of the test. A comparison of mortality ranked the sensitivity of the life stages: Larvae (LC50 = 3.8 mg kg(-1)) > protonymphs (LC50 = 5.3 mg kg(-1)) > males (LC50 = 5.6 mg kg(-1)) > deutonymphs (LC50 = 7.1 mg kg(-1)) > females (LC50 = 7.6 mg kg(-1)). Effects on reproduction and pgr were significant at 2 mg dimethoate kg(-1), with population decline starting at this concentration. Thus, a test system with H. aculeifer including reproduction as end point is a rational approach, as reproduction will encompass juvenile mortality, at least with respect to dimethoate. Moreover, we suggest that pgr should be included in chronic standard tests because of high ecological relevance and the feasibility of applying it.

Animals↗
PubMed1999

Genetic differentiation of mites of the genus Chorioptes (Acari: Psoroptidae).

In an effort to clarify the species status of mites of the genus Chorioptes the second internal transcribed spacer of the rRNA gene was characterized in 14 isolates from cattle, horse, sheep and llama of different geographic origins. The genotypes segregated into two clearly separated groups of DNA sequences. In addition, two phenotypes could be distinguished by the lengths of the outer opisthosomal setae of male adults which had previously been designated as Chorioptes bovis and Chorioptes texanus. The bipartite division of genotypes and phenotypes correlated completely in all isolates. Nine out of ten cattle isolates from three continents were determined to be C. texanus including the first description in Europe and Northern America. Chorioptes texanus appears to have a wider geographic distribution than previously known. Chorioptes bovis was found in four different host species. The apparent lack of host specificity of both species implicates a potential that mites are dispersed freely in a wide range of hosts and this might have contributed to the wide geographic distribution of these species.

Acari↗
PubMed2000

Do herbivore-induced plant volatiles influence predator migration and local dynamics of herbivorous and predatory mites?

If predators lack information on the prey's position, prey have more chance to escape predation and will therefore reach higher population densities. One of the many possible cues that predators may use to find their prey are herbivore-induced plant volatiles. Although their effects on the behaviour of foraging predators have been well studied, little is known about how these prey-related odours affect predator-prey dynamics on a plant. We hypothesise that herbivore-induced plant volatiles provide the major cue eliciting predator arrestment on prey-infested leaves and that the response to these volatiles ultimately leads to lower prey densities. To test this hypothesis experimentally, we created two types of odour-saturated environments: one with herbivore-induced plant volatiles (treatment), and one with green-leaf volatiles (control). An odour-free environment could not be tested because herbivores require plants for population growth. We measured the rate at which predatory mites (Phytoseiulus persimilis) immigrate, emigrate and exploit a single leaf infested by two-spotted spider mites (Tetranychus urticae). The experiments did not show a significant difference between treatment and control. At best, there was a somewhat higher rate of predator (and possibly also prey) emigration in the treatment. The lack of a pronounced difference between treatment and control indicates that at the spatial scale of the experiments random searching for prey was as effective as directional searching. Alternatively, predators were arrested in the prey patch by responding not merely to herbivore-induced plant volatiles, but also to other prey-related cues, such as web and faeces. Based on our current experience we advocate to increase the spatial scale of the experiment (> 1 m2) and we provide other suggestions for improving the set-up.

Animals↗
PubMed2000

Do kin selection and intra-sexual selection operate in spider mites?

Between the two subsocial spider mites, Schizotetranychus longus Saito and S. miscanthi Saito, a big difference exists in male reproductive behavior. The males of the former species have an extraordinarily mild relationship with conspecific males, whereas those of the latter species show mortal aggression against conspecific males. Field and experimental observations on the structure of mating populations showed that S. longus is under inbreeding conditions because of a lack of males in early spring, whereas S. miscanthi is under outbreeding conditions. Therefore, I hypothesized that the difference in male antagonism between the two species may reflect the difference in relatedness of males, that is, it has evolved by kin selection. The recent discovery of two clinal trends in male-male aggression in S. miscanthi provided evidence in favour of this hypothesis. Furthermore, a correlation analyses between experimentally evaluated male aggression and distribution patterns of males in the field indicated that the variation in male antagonism is actually reflected in field populations. Based on these studies, I discuss the solidity of the kin-selection hypothesis. Lastly I address how spider mites are fruitful model animals for conducting behavioral, ecological and genetic studies to understand the evolution of haplo-diploidy.

Animals↗
PubMed2001

Distortion of the spermathecae of phytoseiid mites (Acari: Phytoseiidae) in slide preparation.

The shape and dimensions of the spermathecae are taxonomically important characteristics in phytoseiid mites. In experiments with Neoseiulus californicus (McGregor) and Typhlodromus pyri Scheuten, the shape of the cervix of the spermatheca changed considerably and its diameter was increased by 42-49% when mites were flattened, compared to being mounted with 140 microm spacers underneath the coverslips. Dimensions of the dorsal shield were also affected by flattening. increasing by 3-5%.

Animals↗
PubMed2001

Species association among predaceous and phytophagous apple mites (Acari: Eriophyidae, Phytoseiidae, Stigmaeidae, Tetranychidae).

Predator-predator, predator-prey, and prey-prey associations among nine species of mites were studied in a plot of 100 'Red Delicious' apple (Malus pumila Miller) trees from 1990 to 1997. In 1990, seven-year-old trees were inoculated with Panonychus ulmi (Koch), Tetranychus urticae Koch (Acari: Tetranychidae) or both, and sprayed with azinphosmethyl (alone or plus endosulfan), or nothing. The species Zetzellia mali (Ewing) (Acari: Stigmaeidae), Amblyseius andersoni Chant (Acari: Phytoseiidae), Eotetranychus sp., Bryobia rubrioculus (Scheuten) (Acari: Tetranychidae), and Aculus schlechtendali Nalepa (Acari: Eriophyidae) were already present or immigrated into plots, and Galendromus occidentalis (Nesbitt) and Tvphlodromus pyri Scheuten (Acari: Phytoseiidae) were introduced. Yule's V association index was used to measure positive, neutral, or negative interspecific associations for each species pair, because of its robustness with spatially autocorrelated data. We found that pesticide and release treatments did not greatly affect the association results, but there were strong seasonal differences. Predator-predator associations were the strongest and most consistent, showing negative associations in the early and mid seasons, and neutral ones in late season. Negative associations of T pyri with other predators were the strongest, which is consistent with evidence that this mite can detect other predators on a leaf. Predatorprey seasonal associations were mixed, with some positive and others negative, with most significant associations occurring in the mid season. One prey-prey interaction was positive, again in mid season, most likely because of similar habitat preferences.

Animals↗
PubMed2001

Extracting aquatic mites from stream substrates: a comparison of three methods.

Aquatic mites (Hydrachnida, Oribatida, Halacaroidea) are diverse, and can reach high densities in the substrates of streams and rivers. Although they are a ubiquitous component of these habitats, their small size means that they are often overlooked. Using substrate samples from streams in tropical Queensland, I compared the thoroughness and time-based efficiency of three methods of extraction: sorting live samples without magnification (live-picking); exhaustive sorting of preserved samples using a dissecting microscope (microscope-picking); and kerosene-flotation of preserved samples followed by sorting with a dissecting microscope (kero-float). Live-picked samples yielded significantly fewer individuals and species than other methods, and were biased towards larger species. Oribatids and halacarids were not found when live-picking was used. Live-picking and kero-float methods provided similar numbers of mites per minute of sampling effort, whereas microscope-picking had a lower efficiency than kero-float. A combination of live-picking and kerosene-floatation is recommended for thorough surveys of stream acarofauna.

Animals↗
PubMed2001

Trade-offs in performance on different plants may not restrict the host plant range of the phytophagous mite, Tetranychus urticae.

We examined sib-mated lines of the phytophagous mite, Tetranychus urticae Koch, for trade-offs in performance on different plants. We found no significant trade-offs among 10 potential host plants examined. Trade-offs in performance were not detected in most cases, even when the variations in general performance (mean performance on all potential host plants) among the sib-mated lines were statistically adjusted, denying the possibility that this may be due to the variations in general performance among the lines. No evidence for trade-offs was obtained in an artificial selection experiment; on all tested plants, a line adapted to one marginal host plant exhibited higher performance than the control line. However, the general performance seemed to be negatively correlated with other adaptive traits of the mite, such as competition ability of adult males for their mates and overcrowding response of adult females. Such correlations may contribute to the maintenance of genetic variation in the general performance of T. urticae.

Animals↗