Lice is an infection of the hair and skin of humans with arthropods (insects) called Pediculus capitis (head lice), Pediculus humanus (body), and Phthiris pubis (pubic lice). Head lice and body lice have slightly different appearances on microscopic examination and have different behavior patterns, but are genetically identical. It is thought that head lice evolved from body lice, as head lice lack a single gene that is found in body lice. Head lice lay nits on the shaft of hair, usually around the ears or nape of the neck, while body lice live and lay eggs on clothing, and move onto the body only to feed. Pubic lice are easily differentiated from body and head lice, and live on the hair of the genitalia, and occasionally on eyebrows and lashes. Genetic evidence suggests that lice have been parasites of humans since antiquity. The earliest lice infestation was identified in human hair obtained from an archaeological site in Israel, from an individual dated to be over 9,000 years old. Infestation with body lice is of public health importance because three diseases are transmitted by bacteria that are able to infect Pediculus humanus, namely trench fever (agent, Bartonella quintana), relapsing fever (Borrelia recurrentis), and epidemic typhus (Rickettsia prowazekii). All three infestations are typically associated with military or civilian populations disrupted by war, but sporadic infections may occur.