According to another article[0], > Thoemmes also sampled ten 18-year-olds and found Demodex DNA on just 70 percent of them. This fits with what earlier studies

According to another article[0], > Thoemmes also sampled ten 18-year-olds and found Demodex DNA on just 70 percent of them. This fits with what earlier studies had shown—the mites seem to become more common with age. They’re rare on babies, more common on teenagers, and universal in adults. No one really knows where we get them from. Dogs get their face-mites during nursing, and humans might do the same—after all, one study found a lot of Demodex living in nipple tissue. But the fact that some teens aren’t colonised suggests that we pick up these creatures throughout our lives. [0] http://phenomena.nationalgeographic.com/2014/08/27/you-almost-certainly-have-mites-on-your-face/ http://phenomena.nationalgeographic.com/2014/08/27/you-almos...