Head-to-head contact with an already infested person is the most common way to get head lice. Head-to-head contact is common during play at school, at home, and elsewhere (sports activities, playground, slumber parties, camp). Although uncommon, head lice can be spread by sharing clothing or belongings.
A person gets head lice because the insects crawl from person to person by direct contact or by sharing items — including combs, brushes and hats — with another person who has head lice. Poor hygiene doesn't cause head lice.
The longer answer goes back over 800,000 years. Scientists believe head lice began to evolve on a different path than body lice about the time humans started to wear more clothing. Body lice evolved to attach to clothing fibers which are typically thicker and stronger than a human hair. Head lice stuck with the scalp.
It's less common for head lice to spread without direct contact. But the insects may spread from one person to another through personal items, such as: Hats and scarves. Brushes and combs.
You can get lice by coming into contact with either lice or their eggs. Lice can't jump or fly. They spread through: Head-to-head or body-to-body contact.
In fact, adults can get lice anytime their hair is in close contact with the hair of someone who has lice. Whether public transportation, concerts, or crowded areas, any situation in which there is hair to hair contact puts adults at risk of getting lice.
The oldest physical evidence of head lice on a human was a nit found on the hair of a 10,000-year-old body at an archeological site in Brazil. Lice combs have been found in the tombs of Egyptian royalty, and even Cleopatra was said to have solid gold lice combs buried with her.
Medieval folklore suggests that lard was used to try and suffocate lice and nits off of a scalp. Others propose simply keeping the hair combed through and clean was of so little a priority that no one even bothered with lice.
Lice cannot live apart from their human host so a dirty kitchen or bathroom is not a factor at all. Instead, head lice are transferred from human to human by contact.
While head lice live in your hair and feed on your scalp, body lice usually live in your clothes and bedding. They travel to your skin several times a day to feed on blood. Your clothing seams are the most common places for body lice to lay their eggs (nits).
Lice are attracted to the blood they get through your scalp – short, long, clean or dirty.
Head lice are spread by direct contact with the hair of someone who is infected. The cause of head lice infestations in children is not related to cleanliness. Other animals, such as cats and dogs, do not play a role in transmission. Head lice feed only on human blood and are only able to survive on human head hair.
Their full life cycle, from egg until death, lasts a maximum of 35 days. The eggs are called nits and hatch into small insect forms — called nymphs — which then grow into adult lice. The adult lice can begin to create more eggs as soon as they hatch and the cycle begins again.
A common misconception is that pubic lice are spread easily by sitting on a toilet seat. This would be extremely rare because lice cannot live long away from a warm human body and they do not have feet designed to hold onto or walk on smooth surfaces such as toilet seats.
There are recent studies that show that treatment of lice with heat can be quite effective in killing head lice. Products such as Lousebuster are very effective but even a home hairdryer can successfully treat lice.
Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.
Head lice survive less than one or two days if they fall off the scalp and cannot feed. Head lice eggs (nits) cannot hatch and usually die within a week if they do not remain under ideal conditions of heat and humidity similar to those found close to the human scalp.
The most likely explanation is that by the time H. sapiens evolved in Africa about 200,000 years ago we had our own lineage of head lice, and then picked up more from H. erectus on our travels, says Reed.
Parasites such as lice have a role in the conditioning of a 'natural' immune system and reducing the likelihood of immune dysfunctions, a study of mice from a Nottinghamshire forest indicates.
Adults are not immune to head lice. In fact, if you have any close contact with children or even parents of children you can be at risk of catching them if they have them. Lice transfer primarily through head to head contact, so you would have to get close to the other person.
There is no specific hair type that lice prefer. All lice need is a clean strand of hair to attach to. It doesn't matter the thickness, the length, if it's been colored, if it's straight, or if it's curly. It has been found that people with longer hair tend to report getting lice.
Infestation timeline
So if you look on the scalp and see no visible adult lice and several small nits, it's likely that you've caught lice in the earlier stages and had them for less than 2 weeks. Nits and nymphs: 1.5 to 2 weeks. If you see nits and small, moving lice, you've likely had lice for 1.5 to 2 weeks.
Suffocate the Lice
Soak your child's head in olive oil or coconut oil. Cover with a shower cap for at least 2 hours (or preferably overnight). When ready, remove the shower cap, and separate the hair into small sections, then use a metal nit comb to carefully remove the lice and eggs. Rinse the hair well with shampoo.
Permethrin lotion, 1%;
Permethrin lotion 1% is approved by the FDA for the treatment of head lice. Permethrin is safe and effective when used as directed. Permethrin kills live lice but not unhatched eggs. Permethrin may continue to kill newly hatched lice for several days after treatment.
Just like with mattresses, lice can only live on any bedding—whether it's sheets, pillows, or comforters—for 1-2 days. Without a human scalp as a source for food (blood) for longer than 1-2 days, lice cannot survive.