• A blood-sucking parasite known as Pediculus humanus capitis that can cause an itchy scalp; infestations are highly contagious and especially common in school-age children.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• (louse) Small, wingless, parasitic insects; though exact taxonomy is still controversial, they can be grouped in the orders Anoplura (sucking lice), Mallophaga (biting lice), and Rhynchophthirina (elephant-lice).
  CRISP Thesaurus
  National Institutes of Health, 2006
• (phthiraptera) An order of small, wingless parasitic insects, commonly known as lice. The suborders include ANOPLURA (sucking lice); AMBLYCERA; ISCHNOCERA; and Rhynchophthirina (elephant and warthog lice).
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• Lice can infect the scalp, body, pubis, and eyelashes. Head lice are transmitted by close contact; body lice are transmitted in cramped, crowded conditions; and pubic lice are transmitted by sexual contact. Symptoms, signs, diagnosis, and treatment differ by location of infestation.
  Merck Manuals
  Merck & Co., Inc., 2025
• Lice are tiny, wingless, parasitic insects that feed on human blood. Lice are easily spread - especially by schoolchildren - through close personal contact and by sharing belongings.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research, 2025