Changing Planet

Head lice trigger body lice epidemics, study finds

You can stop scratching your head about the origins of human body lice.

Body lice, which cause highly lethal epidemics (trench fever, typhus and relapsing fever Borrelia), originate from head lice, an international group of scientists reported today.


Image of body louse (Pediculus humanus humanus) courtesy of CDC

 The discovery indicates that it is not possible to eradicate body lice without first eradicating head lice, which until now has proved impossible, according to the researchers.

“This has recently been shown by a team from the Emerging Infectious and Tropical Diseases Research Unit (CNRS/IRD/Université de la Méditerranée), in collaboration with researchers from the Universities of Florida and Illinois” in the U.S., says a news statement released by the French National Center for Scientific Research (CNRS).

The research is published in the March 24 issue of the journal PloS Neglected Tropical Diseases.

“Until now, head lice, which feed on the scalp and lay their eggs on hair, and body lice, which feed on the rest of the body and live in the creases of dirty clothes, were thought to be different species. However, researchers from the Emerging Infectious and Tropical Diseases Research Unit (CNRS/IRD/Université de la Méditerranée) and two U.S. teams have shown that these lice have the same origin,” CNRS said.


Image of head louse (Pediculus humanus capitis) courtesy of CDC

Through genetic analysis of the louse genome, the researchers observed that “it was impossible to distinguish the head louse from the body louse at the genetic level,” CNRS added.

“In addition, fieldwork has shown that, in populations living in extreme poverty, the proliferation of head lice led to the emergence of lice able to adapt to clothes and turn into body lice. These body lice were then able to cause epidemics of body lice and bacterial epidemics.”

“This discovery shows that it is not possible to eradicate body lice without first eradicating head lice, which until now has proved impossible. In addition, this explains the regular appearance of body lice in areas where they were previously unknown, when sanitary conditions rapidly deteriorate.

“Head lice are therefore permanently in an endemic state. In highly unfavorable sanitary conditions, head lice proliferate, and some of them migrate into clothes, triggering a new epidemic of body lice,” CNRS said.

Life cycle of the head louse

Information provided by U.S. Centers for Disease Control & Prevention

The life cycle of the head louse has three stages: egg, nymph, and adult

lice-lifecycle-illustration.jpgEggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets.  Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp (no. 1 in the illustration above). They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp.

Nymphs: The egg hatches to release a nymph (no. 2). The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts (no. 3, no. 4 ) and become adults about 7 days after hatching .

Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white (no. 5). In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. 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.

How do you get head lice?

Getting head lice is not related to cleanliness of the person or their environment, according to the CDC.

“Head lice are spread by direct contact with the hair of an infested person. The most common way to get head lice is by head-to-head contact with a person who already has head lice. Such contact can be common among children during play at school,  home, and  elsewhere (e.g., sports activities, playgrounds, camp, and slumber parties).

“Uncommonly, transmission of head lice may occur by wearing clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons worn by an infested person; using infested combs, brushes or towels; or lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with an infested person, the CDC says.

Forty years in U.S., UK, and South African media gives David Braun global perspective and experience across multiple storytelling platforms. His coverage of science, nature, politics, and technology has been published/broadcast by the BBC, CNN, NPR, AP, UPI, National Geographic, TechWeb, De Telegraaf, Travel World, and Argus South African Newspapers. He has published two books and won several journalism awards. He has 120,000 followers on social media. David Braun edits the National Geographic Society blog, hosting a global discussion on issues resonating with the Society's mission and initiatives. He also directs the Society side of the Fulbright-National Geographic Digital Storytelling Fellowship, awarded to Americans seeking the opportunity to spend nine months abroad, engaging local communities and sharing stories from the field with a global audience. Follow David on Facebook  Twitter  LinkedIn
  • debbie

    I got headlice from my g.daughter whch is in grade school!! They were able to get rid of theirs however,I have done everything from cleaning to all over the counter products,all natural products and am now on my 3rd different prescription and nothing is working so I shaved my head and I still have them!!! I have the bites to prove it!! Now they are traveling all over me!!!! Can someone please help me??? I don’t know what to do!!!

  • Stepf

    Debbie…we use Neem Oil added to our conditioner…works a treat – about 10 drops in normal amount of conditioner, leave on about 10 mins & comb wit lice comb before rinsing out then comb again once rinsed. we do this once a week. Neem oil kills the eggs & lice, & leaves your hair with a nice shine 🙂 can be bought from Health food shops
    there is another remedy…
    Coconut oil + apple cider vinegar to treat head lice. … Coconut oil dissolves the lice’s outer skeletal shell instantly. So once you put it on someone’s head you can have them shower and rinse it off right away and all the lice will be killed and gone! Plus there are no chemicals!

    Here is what to do

    Getting lice in the family is truly horrifying & if you don’t get rid of them ASAP, they will get into everything & literally take over. Not fun. The really important thing is to find an effective treatment that doesn”t require putting harsh chemicals onto your head, which then get absorbed into your body. Yuck. So, here is a tried & tested effective remedy to wipe out those critters in one foul swoop!You will need: A jar of coconut oil & a bottle of apple cider vinegar.

    First, rinse your hair with the vinegar, don’t wash it out, leave it in until it dries. The vinegar dissolves the ‘glue’ which sticks the eggs to your hair follicles. When the vinegar has dried, pour coconut oil into your hair, making sure you get complete coverage. Cover your hair with a shower cap or hair wrap & leave it in for the whole day, as it will take a few hours for the coconut oil to smother & kill the lice. Comb your hair to get as many of the eggs & lice out as possible and then shampoo as normal. You only have to do this once, it really works & no chemicals! Oh, & the coconut oil makes your hair beautiful & shiny, so your getting a lush hair treatment at the same time!
    Hope either one helps with your problem 🙂

  • Dawn M

    Debbie, they are living in your bed or furniture, if you are becoming reinfested. Spray ALL furniture, beds, pillows, cars, pet bedding. Vacuum thoroughly all carpers and furniture. Wash all bedding in HOT water & dry on highest possible temp. Put things you can’t wash (stuffed animals, decorative pillows) into bags out in the sun. Run all your brushes & combs through the sterilize cycle if your dishwasher, or soak them in water that is boiled on the stove. Re-treat in one week, and again , every week for 2-3 months.
    As a teacher, I see this often, and the biggest reason they return is failure to treat the entire house, even if you can’t see them. Also, put about 20-30 drops of Tea Tree Oil in your shampoo and conditioner. It isn’t exactly a pleasant smell, but it is better than the chemicals to treat lice, & it can help prevent them.
    Good luck eradicating them.

  • sandra

    My daughter and I were infected with lice 6 months ago. I have tried every possible treatment including oral treatment of stromectum/Ivermectin. I comb my hair between 2 to 4 hours a day. When l took the ivermectin, I simultaneously treated my hair with non toxic Clear lice product. Since I could still feel them a week later. I actually left a perimthin shampoo in my hair overnight. The next morning the lice moved to my body and now have these creatures getting into the hair follicles of my skin. They are still in my hair and I have stopped treating my hair so that they will move away from my body. The more agressive I got, the more agressive they got. I used so many bottles of olive oil and vinegar to aid in coming them out but to no avail. I did not know they could mutate to adapt to skin. I spend so much time cleaning and combing that have not been able to devote adequate attention to my daughter’s hair. But as it turns out she only has a few nits and they have not moved to her body. These nits are extremely small and the adult stage bug is 1/2 centimeter long at best. Is this a super lice or somthing totally different? A mitosis of the bug?
    – Exhausted and Depressed

  • clarence

    Like me friend said: “Even the toilets gotta Eat but lice will be the reason we turn to Zombies. Watch. Lice that turn u in to a flesh eating zombie 🙁

  • Phil

    @ least their not scabies, have had a bit of a scare trying to find out what it was. Noone could help, Drs, Gov, Lsns, Exterminatior u name it. Was researching on the microscope and finally got the the bottom of this. Now it’s prsyers to try to eradicate them. Been since July been living a nightmare!

  • Sandy

    We had *what I would believe were* the super lice in our house a few months back. Tried multiple otc treatments, nothing worked. Did 3 listerine treatments and they were gone. Just soaked her head in the old traditional gold listerine (other flavors don’t work as well), put on a shower cap, let her sit for an hour or 2, then nit-combed. Did it every 2 days, for a week, and they were gone. I ended up with it shortly after my daughter was first infected. Caught it earlier, so only did 2 listerine treatments and gone!!!

  • Nat

    I have been struggling with some type of ‘super lice’ for ages now. It seems that I have lice’ that live on my head but I fear they are also living on my clothes. Every day I use tea tree oil in shampoo and comb through. Clothes being washed at 60 degrees. Been going through serious home cleaning regime but nothing seems to rid them. In despair!

  • Karen Sewell

    This message is for Debbie in Maryland, USA.

    We’ve had a similar experience with a family member. Started out with head lice and ended up with body lice! Managed to get rid of the head lice, but not with head lice products ( spent a fortune and tried the lot), but used tea tree shampoo / conditioner and used the combing method ( this apparently breaks the legs of the louse). That process took about 8 months, but was left with body lice. Again, tried all prescribed medication, but was hopeless! Resorted to calamine lotion because heard it was used by divers to treat water lice infections. It finally took 2 years approximately to be almost rid of these nasty bugs. The secret is to dry them out and contain them. If you think the infection is dried out and remove the dead skin and are mistaken, then you’ll get another infection. Be also aware to keep nails super clean (eggs get underneath). In our experience, despite what the so call experts think, this problem is bigger and more widespread them people think. The reason is-people don’t want to admit they have the problem because it was ( and still is) associated with poor and unsanitary living conditions. As we all know this is not always the case now. Don’t despair because they will eventually go. The body lice also don’t like being exposed to sunlight (it drys them out). This is just our experience and we won the battle in the end, as you will too.

    ps It always baffled me how a person could start off with head lice and end up with body lice. I’m now amazed to read this article regarding what the scientists have found out. Suffice to say, I’m not surprised because we have experienced it.

  • Becky

    I’ve had head and body lice for almost 4 yrs. I’ve tried everything from shampoos, creams, foggers, boiling all my clothes for 7 hrs, ironing everything, I even stood in the shower and set a lice killing fogger off in the shower with me in it. I held a wet towel over my face and cried and screamed through the whole thing. They didn’t budge. The worst part of all of this is that no one believed me!! Not even my own daddy, son, sisters, doctors, nurses, best friends…. No one!! Well, guess what? Everyone’s got em now. I’m talking about at least 1/2 of the town I live in has super lice! It’s f*”#ed up! No one can get rid of them! I’m not going to go another year with em. I’ve been trying to get rid of them and I’ve prayed, begged, cleaned and cleaned and I give up!! I can’t get a gd doctor to do a simple skin scrape and see!!! Why??? Why don’t people believe me? Of course all the ones that have em now are so sorry they didn’t listen to me and funny, half of em won’t even admit they have em!! But you can see em in their hair and the sores on their bodies!!! Anyway, I give up!! I’m done!! Peace out!!

  • michelle barrow

    I have had head lice for 2 years and they have adapted to living all over my body and I can’t get rid of them. I have tried everything

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