Head Lice: Where Do They Come From? - Healthline

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Where Do Lice Come From?

Medically reviewed by Amanda Caldwell, MSN, APRN-C — Written by Erica Roth — Updated on October 24, 2022

What they are
Origins
Evolution
Transmission
Stigma
FAQs
Takeaway

Lice originate from different geographic regions, depending on the type. You may be most familiar with head lice, which are unpleasant but essentially harmless. Other types are body lice or pubic lice.

A parent checking their child's hair for head lice. — freemixer/Getty Images

Lice are extremely contagious insect parasites that cause an infestation known as pediculosis.

The term “lice” can refer to three types of insect parasites that infect humans: head lice (Pediculus humanus capitis), body lice (Pediculus humanus corporis), and pubic lice (Pthirus pubis).

In many cases, when people talk about lice, they usually refer to head lice. These microscopic insects live in your hair, close to your scalp.

Read on to learn more about lice and where they come from.

What are lice?

Lice are insect parasites. This means they must feed off another living body to survive. Their source of food is human blood, which they get from your body or scalp.

They can’t fly, aren’t airborne, and can’t live in water very long away from their host. Head lice, for example, cling to hair strands for dear life when you bathe.

But where do they come from in the first place?

Geographic origins

Experts categorize human lice into clades based on their genetic makeup. A clade is a group of organisms that are not genetically identical to one another but share a common ancestor.

The clades of human lice, A, B, C, D, and F, have different geographic distributions and genetic characteristics.

For example, according to research, clade B head lice may have originated in North America but migrated to farther reaches of the world, including Australia and Europe.

Human evolution and lice

Lice species affected other primates, such as gorillas and chimpanzees, at some point in history. Beginning somewhere around 13 million years ago, specific species began to evolve to affect only humans.

About 42,000 to 72,000 years ago, human lice separated into head and body lice. The discovery of genetic differences between head and body lice supports theories that this time period is when people began wearing clothing.

While head lice remained on the scalp, body lice mutated into parasites with claws that can grab onto the smoother fibers of clothing rather than needle-thin hair shafts.

How are lice transmitted?

You can get pubic lice from sexual contact or contact with bedding or clothing. You can get body lice similarly from clothing or from close physical contact with a person who has them.

Head lice are more common in younger children because they require even more physical contact for transmission. Usually, you would have to be in head-to-head contact with a person who has lice.

This can be common in schools or kindergartens, where children are often close together. Sharing combs, brushes, towels, hats, and other personal items can hasten the spread of head lice.

Misconceptions

Getting head lice might make people feel embarrassed because there is still a stigma around it.

Body lice

Body lice tend to pass from person to person in places where people have close physical contact or share resources like beds and blankets, such as shelters.

Different factors may cause a person to live in a place where body lice can spread more easily. This can be related to socioeconomic or health inequities.

Head lice

Head lice are not the same as body lice. People of all genders, ages, and races can get head lice. Having head lice doesn’t indicate a person’s improper hygiene, and head lice don’t carry diseases.

They are most common among children regardless of any social, economic, or housing situation. About 19% of school children worldwide have head lice.

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Frequently asked questions

Here are answers to additional questions about lice and their origin.

Where do lice come from when not on humans?

When not on your body, lice can be on clothing or other personal items that people may share. Most of the time, they transmit through close physical contact. In rare cases, head lice can crawl onto your clothing and onto another person’s hair and scalp, but this must happen quickly. Lice can’t live more than a day or so without nourishment.

Can lice go away on their own?

Getting rid of lice requires treatment. There are medicated shampoos, lotions, and other forms of medication that can remove them. In addition, you would need to throw away or disinfect any items on your body or in your home that may contain them.

How can I protect myself from lice?

Pubic lice are not that common, affecting only about 2% of adults. However, you can protect yourself in the same way you would protect yourself against sexually transmitted diseases (STDs).

For all types of lice, it is a good idea not to share personal items such as hats, scarves, hair accessories, and combs with people.

This is particularly important if you know you have head lice. In addition, give each family member their own bedding, towels, and hairbrushes.

Takeaway

In existence for basically as long as humans have been around, lice aren’t likely to become extinct any time soon. In particular, head lice are very common, and getting them is not an indication of improper hygiene.

Although they can be annoying, proper head lice treatment can eradicate the infestation quickly and painlessly.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Amanzougaghene N, et al. (2020). Where are we with human lice? A review of the current state of knowledge.https://www.frontiersin.org/articles/10.3389/fcimb.2019.00474/full
Boutellis A, et al. (2014). The origin and distribution of human lice in the world.https://www.headlice.org/news/research/Boutellis_Abi-Rached_Raoult_2014_The_origin_and_distribution_of_human_lice_in_the_world_Infection_Genetics_Evolution.pdf
Bragg BN, et al. (2022). Pediculosis.https://www.ncbi.nlm.nih.gov/books/NBK470343/
Deputy Director for Infectious Diseases. (2021).https://www.cdc.gov/ddid/index.html
Fu Y-T, et al. (2022). Human pediculosis, a global public health problem.https://idpjournal.biomedcentral.com/articles/10.1186/s40249-022-00986-w
Hammoud A, et al. (2021). Molecular characterization and genetic diversity of haplogroup e human lice in Guinea, West Africa.https://www.mdpi.com/2076-2607/9/2/257/htm

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Medically reviewed by Amanda Caldwell, MSN, APRN-C — Written by Erica Roth — Updated on October 24, 2022

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