T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Lice (Head) Pediculus humanus capitis

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Phthiraptera
Family: Pediculidae
Genus: Pediculus
Species: P. humanus
Subspecies: P. h. capitis
Trinomial name: Pediculus humanus capitis
Synonym: Pediculus capitis
Common names: Head louse, head lice, Head nits (Lice is the plural of louse).

Pediculus humanus capitis is a tiny, wingless ectoparasite insect that lives among human scalp hairs and feeds on tiny amounts of blood drawn from the scalp. They produce a pediculosis capitis (Head lice infestation). They are a very common problem, especially for kids. They're contagious, annoying, and sometimes tough to get rid of. They don't spread disease, although their bites can make a child's scalp itchy and irritated, and scratching can lead to infection.
Head lice spending their entire life on the human scalp and feeding exclusively on human blood. Humans are the only known hosts of this specific parasite.
They have short stumpy legs that render them incapable of jumping, or even walking efficiently on flat surfaces. They spread easily from person to person by hair contact.

Unless the infestation is heavy, it's more common to see nits in a child's hair than it is to see live lice crawling on the scalp. Lice lay eggs (nits) on hair shafts close to the scalp, where the temperature is perfect for keeping warm until they hatch. They look like tiny yellow, tan, or brown dots. Lice eggs hatch within 1 to 2 weeks after they're laid. After hatching, the remaining shell looks white or clear and stays firmly attached to the hair shaft. This is when it's easiest to spot them, as the hair is growing longer and the egg shell is moving away from the scalp.

The usual treatment since eggs and lice can't be removed by brushing or shaking them off, is by wet combing (lice comb) with conditioner which helps in diagnosis as the headlice can be seen in the foam. They have developed an immunity to some medical creams.

Male human head louse.
  

Male louse
  

Female louse