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Head lice hitched a ride on humans to the Americas at least twice

The parasites’ genetics can give in-depth insights into hosts’ pasts

a single head louse

The DNA of head lice (one shown) tells the story of human migration across the globe, a new study shows.

Vincent Smith/Natural History Museum, London (CC-BY 4.0)

By Jake Buehler

Lice have been bugging humans for as long as our species has been around, and the insects’ genes record the story of their hosts’ global voyages, a study finds. 

Lice DNA suggests that the scalp stowaways rode humans to the New World at least twice — once from Asia many millennia ago, and again much more recently via European colonists, researchers report November 8 in PLOS ONE.