First off, let’s dispel a few common myths – contrary to popular belief, head lice are not carriers of any known infectious diseases. They can infect anyone, at any age and are more of a nuisance than a serious health threat. It doesn't matter how often hair is washed, head lice can appear in any type of hair – clean and dirty. Being well groomed has nothing to do with preventing an infestation; even people with impeccable personal hygiene still get head lice. Also, the human head louse feeds exclusively on human blood; it cannot be caught from any household pets or other animals.

The reason why head lice predominantly infect children is due to the close proximity that most children spend around other children (at school, during sports and other activities). All it takes is one child to bring head lice into a school or gathering and voila, the potential for head lice to spread to other children presents itself.

As for how long head lice have been living on human scalps, well, we need not look further than the mummified pharaohs of Ancient Egypt. Researchers have discovered evidence of head lice on their remains, which would mean that they have been around for at least 3000 years! Incidentally, head lice have also been found in mummified Peruvians from around 1000 years ago.

So they have been hanging around our heads for quite some time now. Nothing new under the sun.

In fact, head lice have been so prevalent in our ancestors, that they are used in tracking migratory patterns of ancient humans in a biological discipline known as archaeogenetics. Here the mitochondrial DNA of female head lice is isolated and studied according to varying patterns of genetic mutation that relate to geographical positions that can tell scientists where certain fossilised remains came from originally.

Who knew that the humble head louse could tell us that much about our ancestral past? Quite amazing really.

What are head lice?

Head lice are tiny, approximately 3 – 4 mm long and about 1 mm wide. They are insects, have six legs, claws and a brownish complexion (varying from light brown to dark). Head lice usually spend their entire life span on a human scalp.

Their eggs (or larval stage) are commonly referred to as nits. Nits are mostly deposited very close to the human scalp, are yellowish white in colour and have the size and texture of a grain of salt. These nits are usually found on the hair very close to the scalp.

Those found further from the scalp (1-2 cm) are most probably dead or already hatched. The best way to tell if the nits have hatched is to pinch them between your fingers. If they don’t pop, then they have already hatched or have perished.

What are the symptoms?

Look out for red rashes and scratch marks on the scalp. Continued itching in these regions could suggest the presence of head lice. Tiny red dots on the neck and behind the ears could be bites from head lice.

Scratch marks or rashes on the scalp are a good indicator of a head lice infestation. Unusual itching on the head or neck is also a common symptom

It is often easier to identify the eggs than the actual head lice themselves, so be on the lookout for tiny, yellowish white, oval shaped eggs that are attached to the bottom of the hair follicle.

Prevention is the best form of defense

The best way to treat head lice is to identify them early on, before they get the chance to spread by laying eggs. A mature female can lay between 3-4 eggs per day which equals roughly 100 per month. The average life cycle duration of a mature head louse is between 3-4 weeks.

In order to avoid an infestation – check your children regularly (every week) by combing their hair under a bright light, paying particular attention to the warmer areas of the head such as the front of the scalp, the nape of the neck and behind the ears.

How do they spread?

The average speed of a human head louse is around 10 cm per minute, 6 m per hour or about 150 m per day. This is about one and a half times the length of a rugby pitch!

Ok, so they ain’t no Usain Bolt, but in the insect kingdom, in relation to their size, they are up there (NB the fastest insect on record is the illustrious American cockroach clocking in at an impressive 5 km/h – taking body size into account, this would be the equivalent of a human being running 330 kilometres per hour, what say you now Mr Bolt?)

Head lice do not have wings and are generally bad jumpers, so they manage to move from person to person when certain items are shared. Items such as clothing (that come into contact with the human scalp and hair, like t-shirts, sweaters etc.), combs (or other hair brushes), bed linen, hats/caps or any other kind of head gear (such as helmets, head bands etc.).

It is very rare that a head louse would leave a human scalp and go shuffling across the dinner table to another potential host person as their short, stumpy legs make walking on flat surfaces extremely difficult.

Once they infect a new host, a female head louse will lay her eggs and then these eggs will hatch within 6-9 days.

What to do when head lice appear in your household

Encourage those without head lice to wear hats or other head covers to protect their hair from coming into contact with them. Take the next three weeks to check every member of the household – introduce it as a daily routine.

Treat everyone who appears to be hosting head lice. Common, traditional home remedies include dousing the hair in mayonnaise or olive oil – the rationale here is to starve the little critters of oxygen. There are some great natural remedies available for those who don’t want to cover their family’s scalps in food condiments. Tea tree oil has been shown to be a very effective remedy for getting rid of head lice and nits.

If it is your children who have become infected, please always let your school know ahead of time.

As mentioned previously, the life cycle of the average head louse is 3-4 weeks, so be prepared to continue treatment for about three weeks to break the cycle of infestation.

Keep combing the hair meticulously with a fine toothed comb after each treatment session. Make sure you wash hair brushes and then soak them in hot water for 5-10 minutes.

Washing certain house hold items that are a frequent point of contact can really help. These would include towels, bed sheets, duvet covers and pillowcases. If you cannot wash these items frequently, place them in a sealed plastic bag for 4-5 days – this should be long enough to get rid of the lice by starving them of oxygen.

Vacuuming carpets and floors frequently is another great precaution.

Controlling head lice: A job for the whole community

Ultimately, controlling head lice requires all the people in a community to act together. So letting others living near you know about the infestation can really help contain the spread.

Obviously this has to be done with keeping the children’s best interest at heart – it is important that a child who has head lice isn’t isolated from the rest of the family, as the persistent itching is hard enough to deal with. Little things like encouraging the wearing of hats or head covers and tying up long hair in a bundle can really help contain the spread. That and treating the infection early on.

And remember, you can never do too much combing! Here’s to a nit free year for all..

Thursday Plantation Tea Tree Head Lice Kit assists in naturally controlling head lice and nits and is appropriate for the whole family.

by Christopher von Roy BSc, MSc, DCP Immunology

References

http://www.mayoclinic.org/diseases-conditions/head-lice/basics/definition/CON-20030792
http://news.nationalgeographic.com/news/2008/02/080208-mummies-lice.html
https://www.smartlivingnetwork.com/hair-and-skin/b/head-lice-amazing-facts-you-wont-believe/
http://www.minedu.govt.nz/~/media/MinEdu/Files/…/HeadliceAndNits.doc
http://en.wikipedia.org/wiki/Head_louse
http://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/headlice

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Have you had to deal with head lice in your family? If so, what treatments worked best? Thanks for sharing for your experience with us.