“Head lice have been stigmatized, quickly conjuring images of infested school children and parents combing through their hair. This social stigma reaches many of the estimated 14 million people who are annually infested in the U.S. alone. However, these blood sucking lice have had a long and complex evolutionary history tied to humans and other mammals. In total, there are 532 species of blood sucking lice and each species parasitizes one or just a few mammal species.”
MOLECULAR BIOLOGY AND EVOLUTION (OXFORD UNIVERSITY PRESS).
See full article: “Lice and bacteria, partners in parasitism.”