Demodex injai: a new species of hair follicle mite (Acari: Demodecidae) from the domestic dog (Canidae).

Department of Ecology and Evolutionary Biology, University of Connecticut-Hartford Campus, 85 Lawler Road, West Hartford, CT 06117-2697, USA.
Journal of Medical Entomology (Impact Factor: 1.82). 04/2003; 40(2):146-9. DOI: 10.1603/0022-2585-40.2.146
Source: PubMed

ABSTRACT Demondex injai sp. nov. is described from the hair follicles of a domestic dog in Columbus, OH in October 1996. The mites occupy follicles from the orifice down to and into the sebaceous glands. The individual host may harbor both this new species and D. canis. A comparison of these two species is provided for identification purposes.

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    ABSTRACT: The identification of Demodex injai as a second Demodex species of dog opened new questions and challenges in the understanding on the Demodex-host relationships. In this paper, we describe the development of a conventional PCR technique based on published genome sequences of D. injai from GenBank that specifically detects DNA from D. injai. This technique amplifies a 238-bp fragment corresponding to a region of the mitochondrial 16S rDNA of D. injai. The PCR was positive in DNA samples obtained from mites identified morphologically as D. injai, which served as positive controls, as well as in samples from three cases of demodicosis associated with proliferation of mites identified as D. injai. Furthermore, the PCR was positive in 2 out of 19 healthy dogs. Samples of Demodex canis and Demodex folliculorum were consistently negative. Skin samples from seven dogs with generalized demodicosis caused by D. canis were all negative in the D. injai-specific PCR, demonstrating that in generalized canine demodicosis, mite proliferation is species-specific. This technique can be a useful tool in the diagnosis and in epidemiologic and pathogenic studies.
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