Life Cycle of Head Lice

Head lice infestation is caused by Pediculus humanus capitis, belonging to the family Pediculocidae, an ectoparasite, a parasite that lives on the exterior of its host and that completes the entire life cycle on the scalp of man. The head louse is a hematophagous that survives by sucking the blood of its host every 2–3 hours.  The male louse (approx. 1/16”) is smaller than the female that can reach up to 1/8”.  The female is the most important vector of infection because it lives 35 days after fertilization and lays 8 to 10 eggs per day for a total of up to 300 eggs during its lifetime. From the eggs (nits), nymphs will hatch after 8–12 days and become mature and reproductive in another 8 days. Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets, are grayish white with a shiny surface. The female louse lays one or two eggs and adheres them with a cementing substance at the base of the hair shaft very close to the scalp.