Large-bodied Demodex mite infestation in 4 dogs

Hillier, Andrew; Desch, Clifford E.

doi:10.2460/javma.2002.220.623

Cited by 35 publications

(50 citation statements)

References 8 publications

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“…Demodex injai which lives in the hair follicle and inside the sebaceous gland (Desch and Hillier 2003) are associated with truncal seborrhea oleosa and alopecia (Mueller and Bettney 1999;Hillier and Desch 2002). Finally, a short form of Demodex mite that has tentatively been named Demodex cornei (Shipstone 2000), and which we call Demodex sp.…”

Section: Introductionmentioning

confidence: 96%

Molecular study on three morphotypes of Demodex mites (Acarina: Demodicidae) from dogs

et al. 2012

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Canine demodicosis is a severe and highly prevalent dermatologic disease in dogs. Pet dogs can be affected by three recognized Demodex species that can produce clinical effects. In this paper, three morphological types of Demodex mites have been isolated from Spanish dogs. A complete morphobiometrical study of each one has been carried out. Morphological and biometrical studies revealed three closely related populations with some distinctive characteristics and could be identified as Demodex canis, Demodex injai, and Demodex sp. "cornei." Furthermore, one population of D. canis from China, different populations of Demodex folliculorum from human skin (Spain and China), D. folliculorum from human eyelashes (Spain), and Demodex brevis from human skin (China) were considered to find out the level of variation between different species and geographical origin. The aim of the present study is to assess the usefulness of mitochondrial DNA molecular markers in establishing phylogenetic relationships and resolve taxonomic questions in Demodex mites. Molecular studies based on the amplification and sequencing of the 16S rDNA and cytochrome oxidase I mitochondrial genes did not show clear differences between the three morphotypes considered. Furthermore, phylogenetic relationships in Demodex mites were analyzed. The resulting phylogenetic trees show that Demodex species from dogs were gathered together, and populations of D. folliculorum from humans appear together in a different branch; however, D. brevis from humans seemed to be more distant. Our results show that cytochrome oxidase I region is a useful tool to solve different taxonomic questions at the species and population level and to infer phylogenetic relationships in Demodex species. However, 16S mitochondrial rDNA seems a good marker for comparisons at an interspecies level, but not at a population level in this group of mites. Furthermore, from genetic distance and divergence data, we would suggest that D. canis, D. injai, and Demodex sp. cornei are polymorphisms of the same species.

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Section: Introductionmentioning

confidence: 96%

Molecular study on three morphotypes of Demodex mites (Acarina: Demodicidae) from dogs

et al. 2012

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“…A short‐bodied unnamed Demodex mite has also been associated with canine demodicosis 2–5 . Recently, a new species of Demodex mite has been described and implicated as a causative agent of the generalized form of canine demodicosis 6–9 . This demodecid mite, named as Demodex injai , is a long‐bodied species.…”

Section: Introductionmentioning

confidence: 99%

Demodex injai infestation and dorsal greasy skin and hair in eight wirehaired fox terrier dogs

Ordeix¹,

Bardagí

Scarampella³

et al. 2009

Veterinary Dermatology

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Demodex injai mites were detected on trichoscopic examinations and/or deep skin scrapings in eight wirehaired fox terrier dogs with dorsal greasy skin and hair. Histological examination performed in five dogs revealed marked sebaceous gland hyperplasia with lympho-plasmacytic periadnexal dermatitis in all of them. One mite section was observed in one patient. Seven dogs were parasitologically cured after 2 to 7 months of oral ivermectin treatment. Greasy skin and hair resolved in four dogs, was partially reduced in two dogs and persisted in the remaining dog. Skin biopsies were repeated after parasitological cure in two dogs and revealed the persistence of sebaceous gland hyperplasia with mild lympho-plasmacytic periadnexal dermatitis and no parasites. Based on the findings in this case series, the terrier dog breed might be at increased risk for the development of D. injai mite infestation associated with dorsal greasy skin and hair, and microscopically with sebaceous gland hyperplasia. Persistence of sebaceous gland hyperplasia after parasitological cure in some patients suggested that this histological finding may not always be resulting from Demodex infestation. Moreover, low numbers of adult mites and variable clinical responses to acaricidal therapy suggested a contributory rather than a major role of D. injai in this skin condition. Dermatopathological diagnosis of sebaceous gland hyperplasia, particularly in case of dorsal trunk specimens from terrier dog breeds, warrants the search for D. injai mites on trichoscopic examinations and/or deep skin scrapings.

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“…In humans, the association between D. folliculorum and pityriasis folliculorum, rosacea, perioral dermatitis, and blepharitis is stronger than that between D. brevis and those diseases (Ayres and Ayres 1961;Forton and Seys 1993;Dolenc-Voljc et al 2005). However, in dog, whether Demodex injai or D. canis is pathogenetic remains controversial (Hillier and Desch 2002;Sastre et al 2013). The failure of the culture of Demodex in vitro directly hampers the confirmation of its pathogenicity by Koch's postulates.…”

Section: Discussionmentioning

confidence: 97%

Molecular identification and phylogenetic study of Demodex caprae

Zhao

Juan

et al. 2014

Parasitol Res

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The DNA barcode has been widely used in species identification and phylogenetic analysis since 2003, but there have been no reports in Demodex. In this study, to obtain an appropriate DNA barcode for Demodex, molecular identification of Demodex caprae based on mitochondrial cox1 was conducted. Firstly, individual adults and eggs of D. caprae were obtained for genomic DNA (gDNA) extraction; Secondly, mitochondrial cox1 fragment was amplified, cloned, and sequenced; Thirdly, cox1 fragments of D. caprae were aligned with those of other Demodex retrieved from GenBank; Finally, the intra- and inter-specific divergences were computed and the phylogenetic trees were reconstructed to analyze phylogenetic relationship in Demodex. Results obtained from seven 429-bp fragments of D. caprae showed that sequence identities were above 99.1% among three adults and four eggs. The intraspecific divergences in D. caprae, Demodex folliculorum, Demodex brevis, and Demodex canis were 0.0-0.9, 0.5-0.9, 0.0-0.2, and 0.0-0.5%, respectively, while the interspecific divergences between D. caprae and D. folliculorum, D. canis, and D. brevis were 20.3-20.9, 21.8-23.0, and 25.0-25.3, respectively. The interspecific divergences were 10 times higher than intraspecific ones, indicating considerable barcoding gap. Furthermore, the phylogenetic trees showed that four Demodex species gathered separately, representing independent species; and Demodex folliculorum gathered with canine Demodex, D. caprae, and D. brevis in sequence. In conclusion, the selected 429-bp mitochondrial cox1 gene is an appropriate DNA barcode for molecular classification, identification, and phylogenetic analysis of Demodex. D. caprae is an independent species and D. folliculorum is closer to D. canis than to D. caprae or D. brevis.

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Large-bodied Demodex mite infestation in 4 dogs

Cited by 35 publications

References 8 publications

Molecular study on three morphotypes of Demodex mites (Acarina: Demodicidae) from dogs

Molecular study on three morphotypes of Demodex mites (Acarina: Demodicidae) from dogs

Demodex injai infestation and dorsal greasy skin and hair in eight wirehaired fox terrier dogs

Molecular identification and phylogenetic study of Demodex caprae

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