House Dust Mites in Erzincan Province.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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%). CONCLUSION: 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.

Multiplex PCR for identifying common dust mites species (Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis).

INTRODUCTION: Dust mites are known to be an important source of inhalant allergens causing allergic rhinitis and asthma worldwide. The sizes of dust mite populations in patients' houses are useful to monitor the risk of allergen exposure. However, mite identification using the conventional microscopic technique requires specific expertise and is time consuming; therefore a molecular technique has been developed in order to solve these drawbacks. OBJECTIVE: To develop a multiplex PCR assay for identifying the three common dust mite species in Thailand, namely Dermatophagoides pteronyssinus (Dp), D. farinae (Df) and Blomia tropicalis (Bt), and to evaluate the efficacy of the technique. METHODS: Pairs of primers were designed and tested in either singleplex PCR or multiplex PCR. The multiplex PCR technique was also optimized in order to obtain specific products. The reaction mixture contained 5 pmole of individual primers, 10 mM dNTP, 5 units Taq DNA polymerase and genomic DNA (gDNA). The reaction was run for 25 cycles at 94 degrees C for 20 seconds, 58 degrees C for 20 seconds and 72 degrees C for 30 seconds. The PCR products were analyzed by 1.5% agarose gel electrophoresis with GelRed fluorescence dye. The optimized multiplex technique was also tested with 30 house dust samples and dust samples spiked with DNA from other insect and mite species. RESULTS: Three PCR products were obtained with the relevant gDNA templates as expected; 143 bp for DF, 221 bp for DP and 318 bp for BT, respectively. The detection limit of the tests was found to be as low 1 ng of gDNA, whereas mixed gDNA species confirmed the 100% specificity of this assay. The total duration from the preparation of the PCR reaction mixture until the analysis by agarose gel electrophoresis was approximately 2 hours. No amplified product was obtained from mites and insects of other species. CONCLUSION: The multiplex PCR was successfully developed for identifying 3 common dust mite species. This technique can be helpful, not only for non-acarologist personnel for dust mite identification, but also for patients who are allergic to dust mites.

The fauna and distribution of house dust mites in residential homes of Bandar Abbas District, Southern Iran.

This study was designed to determine the occurrence, distribution and abundance of house dust mites (HDM) in residential homes in Bandar Abbas (Hormozgan Province), because of numerous complaints of allergies in this oriental city. The study area was divided in five sampling zones based on population density and geographical distribution. In each sampling zone 10 houses were randomly selected. A total of 50 home dust samples were collected using a portable vacuum cleaner for 2 min from 1 m(2) of the surface of mattresses, carpets, sofas and furniture in residential houses. After collection, samples were immediately frozen. Mite species were identified and counted using standard methods and keys. Of the sampled houses 88% (44 houses) were contaminated with at least one HDM species. Three species were identified: Dermatophagoides pteronyssinus (63.1%), D. farinae (32.8%) and D. evansi (4.1%) (Pyroglyphidae). Our findings indicate a relationship between HDM density and moisture and temperature of residential places. The high contamination rate of residential houses (88%) and the favourable environmental conditions for these arthropods stress that they should be considered as important allergic causing agents.

[Distribution of house dust mites in Hasköy town, Mus]. / Mus'un Hasköy ilçesinde ev tozu akarlarinin yayilisi.

OBJECTIVE: This study was carried out to determine the distribution of house dust mites and the role of the mites on allergic diseases in Haskoy town, Mus. METHODS: In the study, dust samples were collected from 50 houses in May and July months of 2002 year. RESULTS: Twenty eight (56%) of 50 mites samples examined in May and 20 (40%) of 50 mites samples examined in July were found positive. Dermatophagoides pteronyssinus was found to be the predominant species with 36.34% in May and 34.21%in July. Lepidoglyphus destructor, Cheyletus spp, Acarus spp, Acarus farris, Acotyledon tjidobas, Blomia tjidobas, Rhizoglyphus robini and Chartoglyphus arcuatus had 18.18%, 6.81%, 4.54%, 4.54%, 4.54%, 2.27%, 2.27% and 2.27% percentages in May respectively. On the other hand, L. destructor, Cheyletus spp, Acarus spp, Acarus farris, Allocalvolia habrocytes, A. tjidobas and R. robini had 18.42%, 10.52%, 7.89%, 2.63%, 5.26%, 5.26% and 5.26% in July respectively. CONCLUSION: Positivity rates of the mites collected from houses of people with allergic disorders was 55.5% while this rate was 56.25% for houses of those without allergic disorders. No statistical relationship was found between encounter with the mites and the patients with allergy. In addition, the number of adobes detected dust mites was higher than the other types of houses.

The complete mitochondrial genome of the house dust mite Dermatophagoides pteronyssinus (Trouessart): a novel gene arrangement among arthropods.

BACKGROUND: The apparent scarcity of available sequence data has greatly impeded evolutionary studies in Acari (mites and ticks). This subclass encompasses over 48,000 species and forms the largest group within the Arachnida. Although mitochondrial genomes are widely utilised for phylogenetic and population genetic studies, only 20 mitochondrial genomes of Acari have been determined, of which only one belongs to the diverse order of the Sarcoptiformes. In this study, we describe the mitochondrial genome of the European house dust mite Dermatophagoides pteronyssinus, the most important member of this largely neglected group. RESULTS: The mitochondrial genome of D. pteronyssinus is a circular DNA molecule of 14,203 bp. It contains the complete set of 37 genes (13 protein coding genes, 2 rRNA genes and 22 tRNA genes), usually present in metazoan mitochondrial genomes. The mitochondrial gene order differs considerably from that of other Acari mitochondrial genomes. Compared to the mitochondrial genome of Limulus polyphemus, considered as the ancestral arthropod pattern, only 11 of the 38 gene boundaries are conserved. The majority strand has a 72.6% AT-content but a GC-skew of 0.194. This skew is the reverse of that normally observed for typical animal mitochondrial genomes. A microsatellite was detected in a large non-coding region (286 bp), which probably functions as the control region. Almost all tRNA genes lack a T-arm, provoking the formation of canonical cloverleaf tRNA-structures, and both rRNA genes are considerably reduced in size. Finally, the genomic sequence was used to perform a phylogenetic study. Both maximum likelihood and Bayesian inference analysis clustered D. pteronyssinus with Steganacarus magnus, forming a sistergroup of the Trombidiformes. CONCLUSION: Although the mitochondrial genome of D. pteronyssinus shares different features with previously characterised Acari mitochondrial genomes, it is unique in many ways. Gene order is extremely rearranged and represents a new pattern within the Acari. Both tRNAs and rRNAs are truncated, corroborating the theory of the functional co-evolution of these molecules. Furthermore, the strong and reversed GC- and AT-skews suggest the inversion of the control region as an evolutionary event. Finally, phylogenetic analysis using concatenated mt gene sequences succeeded in recovering Acari relationships concordant with traditional views of phylogeny of Acari.

Molecular identification of pathogenic house dust mites using 12S rRNA sequences.

House dust mites are microarthropods implicated in the cause of allergic diseases. Currently, there is no phylogenetic analysis of dust mites based on genomic or mitochondrial DNA (mtDNA) evidence. For the first time, we report evolutionary relationships based on partial mtDNA 12S rRNA sequences among the four dust mite families Pyroglyphidae (Dermatophagoides pteronyssinus), Glycyphagoidea (Glycyphagus privatus), Acaridae (Aleuroglyphus ovatus), and Echimyopodidae (Blomia tropicalis). Thirteen sequence variants were obtained and phylogenetic analysis showed two monophyletic clades composed of two species each. Contrary to current taxonomic classification, the Acaridae clustered in a monophyletic group with the Pyroglyphidae. Considering the current difficulties in identifying these medically important species for the purpose of eradication and treatment, it is significant that sequence data are capable of discriminating between species belonging to different families of dust mites.