These are Pediculus humanus, or body lice. Other types of lice infest the scalp, head (Pediculus humanus capitis), or the pubic area (Phthirus pubis). Some body lice may carry diseases such as epidemic typhus, relapsing fever, or trench fever. (Image courtesy of the Centers for Disease Control and Prevention.)
Update Date 1/13/2014
Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.