Medically reviewed by Daniel Combs, MD Lice are parasites that survive on your body by living off your blood. Three types of lice impact humans: head lice, body lice, and pubic lice. Head lice, the ...

Lice form the Phthiraptera clade. While people generally fear lice because they live on a human’s body, only three types can harm humans; others live on other warm-blooded hosts. These insects ...