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What is a head louse? A head louse is a wingless parasite that resides on the human scalp drawing blood for nourishment. These lice will infest and spread to a new host by sharing belongings (brushes, combs, hats, towels, clothing or beds) or close personal head-to-head contact. Children are most likely to catch and spread lice. Estimates state that six to twelve million children under the age of 12 become infested with head lice every year.

Head lice can be very challenging and tedious to remove – this is where the term ‘nit-picking’ came from.

Characteristics

  • Head lice are nocturnal
  • Head lice don’t spread disease
  • Head lice have one pair of eyes
  • Head lice don’t have wings, they only crawl
  • An adult louse is about the size of a sesame seed
  • Adult female head lice prefer to attach their eggs to scalp hair
  • Head lice are highly adapted for piercing skin to extract blood
  • The adult head lice lay their eggs (termed “nits”) attached to hair strands
  • Three forms of head lice exist: nits, nymphs, and mature adults
  • Head lice have one pair of antennae, each with five segments, protrude from its head
  • The most common route of lice transmission is by direct contact with an affected person’s hair
  • Since head lice do not have any wings or the ability to jump, they move by using their claw-like legs to transfer from hair to hair, allowing them to move quickly and reach another host

Reproduction

  • Adult head lice reproduce sexually
  • Adult lice mating usually lasts more than an hour
  • Mating occurs during any period of the night or day
  • Copulation can begin within the first 10 hours of adult life
  • Young males can successfully pair with older females, and vice versa
  • The adult female head louse can deposit about 90 eggs, averaging three to four eggs per day
  • Eggs are attached near the base of a host hair strand
  • Eggs hatch six to nine days after incubating
  • Eggs (known as “nits”) are bright, transparent, but appear white after hatching
  • Newly hatched nymphs will molt three times before becoming sexually-mature adults
  • The head louse has a life span close to 30 days

Prevention

  • Use hair products designed to repel lice
  • Vacuum carpets and furniture upholstery
  • If infestations exists, get new combs, brushes, and hair ties
  • Do not share items that touch the head (combs, brushes, hats, scarves, helmets, and caps)
  • Wash affected clothing and items after an infestation in hot water and tumble/dry on high heat
  • Soak combs, brushes, and hair ties in a 10 percent bleach or 2 percent Lysol solution for one hour

Photo By Gilles San Martin – originally posted to Flickr as Male human head louse, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=11208622