Take a really close look at your face and you’ll probably find that two microscopic relatives of spiders and ticks dwell there. The usually benign mites, Demodex folliculorum and D. brevis, wriggle into skin pores and hair follicles, including eyelashes. And every adult may harbor these hitchhikers, researchers report August 27 in PLOS ONE.
Scientists analyzed DNA from skin gently scraped off the noses and cheeks of 29 Americans. They detected genetic material from Demodexmites in skin samples from all 19 adult subjects and 70 percent of those under 18. In earlier studies, researchers pulled the arachnids off 100 percent of human cadavers but only 10 to 25 percent of the living.
The new findings suggest that everyone harbors the mites post-puberty, Megan Thoemmes of North Carolina State University and colleagues say.Logging the genetic samples in a global mite database revealed that D. brevismites differ by geographical region: New World mites were genetically distinct from those living in China. If confirmed on a larger scale, the genetics of D. brevismites could provide insight into human migration over millennia.