What do head lice and mosquitoes have in common?

By Claire Holdreith

You’ve probably heard about head lice at school, maybe even had your hair checked for them, but what are they? Lice are very small insects, about the size of a sesame seed. Have you ever noticed how your hair keeps your head warm? Lice like to live in hair where they are kept warm too. Their 6 legs have claws that are specially adapted for grasping hair so they can crawl along individual hairs and hold on tightly when they get close to the scalp where it is warmest. Being close to the scalp also means that they are close to food. For food they eat tiny amounts of blood, which they suck up in a similar way to a mosquito. Think about the last time you had a mosquito bite. For a few days you probably had a red bump that you couldn’t stop scratching. Lice and mosquitoes both feed on blood by injecting saliva, or spit, under the skin. The foreign saliva gets into our blood and causes a tiny allergic reaction at the spot where we were bitten. This irritates the skin and makes us itch.

But why do they inject their saliva?

The saliva of a louse or a mosquito has an important ingredient, called an anticoagulant. This stops blood cells from sticking together. By injecting a small amount of anticoagulant under the skin, the pest can drink as much blood as it likes without the blood cells sticking together to form a barrier. This barrier formation is important in normal wound healing to keep our blood inside our bodies.

So what can we do about these saliva injecting, hair clawing bugs called lice?

Anyone can get head lice, it is not a sign of how much you wash. They cannot fly but are spread by touching heads or sharing things like hats, combs, headbands, and pillows. This is why lice are really good at spreading around classrooms. Don’t give lice the chance to spread by not sharing hats, combs or hair accessories, and avoid putting your heads together.

It can be tricky to get rid of lice if you already have them. Lice only live for up to 30 days, but they can lay up to 8 eggs per day. The eggs, which are also called nits, look like small blobs on pieces of hair. The lice and eggs must be killed to stop the lice from coming back. There are special shampoos, conditioners and hair creams with medicine in them that kills lice and eggs. Some work overnight while others only take a few hours. After using the special shampoo, an adult will need to comb through the hair with a fine-toothed comb to get any remaining lice and eggs out of the hair. It is easier to remove the lice when the hair is wet because it is harder for the lice to move around. The claws on their legs slip off and are not able to grip very well in wet hair.

If you do get lice, not to worry. They will not hurt you, they just might be an itchy nuisance. Just make sure that an adult knows and helps you to become lice free.