Pediculus spp.

Virtual Microscope


  • Insect: Three part body (head/thorax /abdomen) and 6 legs
  • Dorso-ventrally flattened, size 2-3 mm
  • Wingless
  • Large claws
  • Lice eggs (nits) attached to scalp hair or clothing or pubic hair
  • Permanent ectoparasites
  • Incomplete metamorphosis (hemimetabole) (larvaes look the same as adults), life cycle from egg to adult 17-21 days
  • All stages of development (larvaes + adults) are blood feeders, P.vest. can starve for 7 days
  • Adults become 4 weeks old
  • The female lays about 3-4 eggs per day           

• Medical significance: 

Body louse vector of diseases:

  • Pediculosis; n case of a heavy infestation, it can lead to skin problems
  • Epidemic typhus (Rickettsia prowazeki)
  • Relapsing fever (Borrelia recurrentis)
  • Trench fever (Bartonella quintana)


  • Direct contact (active)
  • Indirect with shared combs, hats, towels,clothing, beds (passive)