High-Definition Optical Coherence Tomography for the in vivo Detection of Demodex Mites

Background: Demodex mites are involved in different skin diseases and are commonly detected by skin scrape tests or superficial biopsies. A new high-definition optical coherence tomography (HD-OCT) with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode might offer the possibility of noninvasive and fast in vivo examination of demodex mites. Methods: Twenty patients with demodex-related skin diseases and 20 age- and gender-matched healthy controls were examined by HD-OCT. Mites per follicle and follicles per field of view were counted and compared to skin scrape tests. Results: HD-OCT images depicted mites in the en-face mode as bright round dots in groups of 3-5 mites per hair follicle. In the patients with demodex-related disease, a mean number of 3.4 mites per follicle were detected with a mean number of 2.9 infested follicles per area of view compared to a mean of 0.6 mites in 0.4 infested follicles in the controls. The skin scrape tests were negative in 21% of the patients. Conclusion: The innovative HD-OCT enables fast and noninvasive in vivo recognition of demodex mites and might become a useful tool in the diagnosis and treatment monitoring of demodex-related skin diseases. Copyright (C) 2012 S. Karger AG, Base

Complete mitochondrial genomes of the human follicle mites Demodex brevis and D. folliculorum: novel gene arrangement, truncated tRNA genes, and ancient divergence between species

BACKGROUND: Follicle mites of the genus Demodex are found on a wide diversity of mammals, including humans; surprisingly little is known, however, about the evolution of this association. Additional sequence information promises to facilitate studies of Demodex variation within and between host species. Here we report the complete mitochondrial genome sequences of two species of Demodex known to live on humans—Demodex brevis and D. folliculorum—which are the first such genomes available for any member of the genus. We analyzed these sequences to gain insight into the evolution of mitochondrial genomes within the Acariformes. We also used relaxed molecular clock analyses, based on alignments of mitochondrial proteins, to estimate the time of divergence between these two species. RESULTS: Both Demodex genomes shared a novel gene order that differs substantially from the ancestral chelicerate pattern, with transfer RNA (tRNA) genes apparently having moved much more often than other genes. Mitochondrial tRNA genes of both species were unusually short, with most of them unable to encode tRNAs that could fold into the canonical cloverleaf structure; indeed, several examples lacked both D- and T-arms. Finally, the high level of sequence divergence observed between these species suggests that these two lineages last shared a common ancestor no more recently than about 87 mya. CONCLUSIONS: Among Acariformes, rearrangements involving tRNA genes tend to occur much more often than those involving other genes. The truncated tRNA genes observed in both Demodex species would seem to require the evolution of extensive tRNA editing capabilities and/or coevolved interacting factors. The molecular machinery necessary for these unusual tRNAs to function might provide an avenue for developing treatments of skin disorders caused by Demodex. The deep divergence time estimated between these two species sets a lower bound on the time that Demodex have been coevolving with their mammalian hosts, and supports the hypothesis that there was an early split within the genus Demodex into species that dwell in different skin microhabitats. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1471-2164-15-1124) contains supplementary material, which is available to authorized users

Controlling external parasites of swine in 1983

Robert D. Hall and Flernoy G. Jones (Department of Entomology, College of Agriculture)Revised 4/83/6

Controlling external parasites on swine

"The major external parasite attacking hogs in Missouri is the hog louse. These insects obtain their food by puncturing the skin of the host animal with their mouthparts and sucking blood. Each time they feed they puncture the skin at a different place. The irritation and itching caused by puncturing the skin causes the animal to rub against any convenient object. The animals may rub off their hair in patches and may even rub hard enough to cause bleeding."--First page.Robert D. Hall and Flernoy G. Jones (Department of Entomology, College of Agriculture)Revised 2/86/4

Controlling external parasites of swine (1993)

This guide describes some of the more common parasites affecting swine and provides recommendations for controlling them

Controlling external parasites of swine

Robert D. Hall and Flernoy G. Jones (Department of Entomology)Revised 12/89/4

Optical coherence tomography of the epidermal sulfakrilate surface strippings

Method of the epidermal surface biopsy (ESB) with the adhesive compositions is the alter-native to the classic his-tological examination. Materials and Methods. In this study medical adhesive "Sulfacrylate" was used, small portions of which had been spread on an object glass, and then on different skin areas. To study the structural organization of the samples ESB the technique of optical coherence tomography (ОСТ) was used. Results. We obtained the pictures that visualize the structural organization of the different layers of the epidermis in lichen planus, hyperkeratosis, scabies and other skin diseases. Conclusion. This technique allows non-invasive measurement of high-precision structure of different layers of the epidermis, which can be useful both for research and for the practical dermatology

Corynebacterium kroppenstedtii subsp. demodicis is the endobacterium of Demodex folliculorum

Background Demodex spp. mites are the most complex member of the human skin microbiome. Mostly they are commensals, although their pathophysiological role in inflammatory dermatoses is recognized. Demodex mites cannot be cultivated in vitro , so only little is known about their life cycle, biology and physiology. Different bacterial species have been suggested to be the endobacterium of Demodex mites, including Bacillus oleronius , B. simplex , B. cereus and B. pumilus . Objectives Our aim was to find the true endobacterium of human Demodex mites. Methods The distinct genetic and phenotypic differences and similarities between the type strain and native isolates are described by DNA sequencing, PCR , MALDI ‐TOF , DNA ‐DNA hybridization, fatty and mycolic acid analyses, and antibiotic resistance testing. Results We report the true endobacterium of Demodex folliculorum , independent of the sampling source of mites or life stage: Corynebacterium kroppenstedtii subsp. demodicis . Conclusions We anticipate our finding to be a starting point for more in‐depth understanding of the tripartite microbe–host interaction between Demodex mites, its bacterial endosymbiont and the human host

Blepharitis and Demodex spp. infection

According to the latest reports Demodex mites appear to play an important role in the pathogenesis of chronic blepharitis. Demodex mites are cosmopolitan and are present in many species of mammals. In this paper we describe two species that are found in humans: Demodex folliculorum and D. brevis. Infection occurs during direct contact with an affected person and also through contact with dust containing eggs of the parasite, through contact with bed linen, as well as cosmetics used together with an affected person. Treatment of chronic blepharitis caused by D. folliculorum and D. brevis is difficult and time consuming. Some improvement can be achieved after topical application of yellow mercury ointment, sulphuric ointment, camphor oil, crotamiton, cholinesterase inhibitors, sulfacetamide, steroids, antibiotics and antifungal drugs. Good results have been achieved with oral ivermectin and permethrin cream. However, the best results were observed after treatment with metronidazole.