Parasite
Pediculus (lice)
Blood-feeding lice; body louse is a disease vector
peh-DIK-yoo-lus
High-yield clue
Nits (eggs) cemented to hair shafts point to head lice, while the body louse is the classic vector for epidemic typhus and relapsing fever.
Overview
Wingless blood-feeding insect ectoparasites; the head louse (P. h. capitis) and body louse (P. h. corporis) are core exam organisms, with the body louse notable as a disease vector. It matters as the classic louse infestation and vector example.
Classification
- Arthropod ectoparasite
- Insect (louse)
- Obligate blood feeder
- Head vs body forms of P. humanus (the pubic louse is Pthirus pubis, a different genus)
Lab & identification clues
- Nits cemented to hair shaft vocabulary
- Adult louse on visual/microscopic exam
- Body louse lives/lays eggs in clothing seams
- Wet-combing detection concept
Associations
- Direct contact / shared items transmission
- Body louse vector: epidemic typhus, trench fever, relapsing fever
- Crowding/poor-hygiene epidemiology framing
- Pubic louse ('crabs') is Pthirus pubis, a separate genus with a sexual-contact study link
Commonly confused with
- Sarcoptes scabiei
- Hair casts / dandruff
Frequently asked questions
What is Pediculus (lice)?
Wingless blood-feeding insect ectoparasites; the head louse (P. h. capitis) and body louse (P. h. corporis) are core exam organisms, with the body louse notable as a disease vector. It matters as the classic louse infestation and vector example.
What are the lab clues for Pediculus (lice)?
Lab clues for Pediculus (lice) include Nits cemented to hair shaft vocabulary, Adult louse on visual/microscopic exam, Body louse lives/lays eggs in clothing seams, and Wet-combing detection concept.
What is Pediculus (lice) commonly confused with?
Pediculus (lice) is commonly confused with Sarcoptes scabiei and Hair casts / dandruff.
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.