Pathogenesis associated with hair follicle mites (Demodex spp.) in Australian Aborigines.

Demodex folliculorum and D. brevis are found in different habitats in the skin: the former in the hair follicles, the latter in the sebaceous glands. Both seem minor pathogens--merely harvesting the cells of their respective habitats. D. folliculorum was found aggregated (all stages) and plugging the follicular orifices; D. brevis, on the other hand, was usually solitary. In one case marked degeneration of the sebaceous gland, with leukocyte invasion, was associated with D. brevis. No correlations were discovered between either of these species and the gross condition of the skin. Positive samples were obtained from both mainland and island populationf of Aborigines. Incidence values obtained were 66.6% for males and 80% for females; in the latter, the sample was small (5) and their ages over 34 years.