Head lice are not dangerous and do not transmit disease. They cause no medical harm and can be effectively treated. Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.
Life cycle of head lice: eggs or nits are cemented to the base of the hair shaft, eggs hatch into nymphs, in 7 days adult lice have matured. Lice can live 30 days on an infected head. Lice will die in 1 – 2 days off the host.
Head lice are spread by direct contact only. They cannot jump or fly.
All people are susceptible to head lice although some groups are more vulnerable than others.
Most students with head lice are symptom free although some may experience itching.
Nits visible farther than 6 mm (1/4 in) from the scalp are generally not viable and an indication of past infestation.
Current infestation is confirmed by inspection of scalp and hair for the presence of nits, nymphs or adult lice. Lice are often difficult to spot because there are few and they move quickly.