Incubation period of lice and nits in humans

It is easy to become infected with lice. A short contact with a carrier of parasites is sufficient (touching hair, clothing in public transport, a public place). “Uninvited guests” immediately get down to business - they bite the new owner, lead their usual way of life (live, reproduce). It is useful for a newly infected person to know how long the incubation period of lice and nits lasts. Timely detection of signs of the appearance of parasites and timely initiation of treatment are the key to a successful outcome.

Lice reproduction

Many people have encountered such a problem as lice in their lives. When infected with pediculosis, a person is looking for a way to get rid of these blood-sucking parasites as quickly as possible and is not at all interested in how they reproduce. However, many scientists are closely observing this process, finding it quite interesting, since it differs from the methods of reproduction characteristic of many other insects.

This happens as follows:

The female is ready to begin mating with the male within the first two days after she has undergone her last larval molt.
Fertilization is internal and occurs very quickly; just a few hours after mating has occurred, the female begins to lay eggs.
The development of eggs and larvae also occurs very quickly, this is due to the fact that the oviposition is located in human hair or animal fur, so the question of lack of food or the need to obtain it never arises.
The eggs are attached to the hair and can be located at varying distances from the roots.
Each egg is equipped with a specific case with a sticky structure, which dries after gluing, so it is attached quite reliably. An egg hidden in such a case is called a nit.
Soon, small insects will hatch from the nits - new offspring of lice.

Which doctor can I contact?

Usually, people try to cope with head lice on their own, using the anti-parasite remedies listed above, without the help of doctors. But, if the carrier person cannot recover from the parasites on his own, then he should consult a doctor. Which specialist should you contact to get rid of head lice?

Doctors such as a primary care physician, dermatologist or trichologist can help in the fight against head lice. They can help you choose products that will not harm the patient but will kill all lice and nits.

Do not neglect treatment of pediculosis as soon as the first symptoms appear:

itching and/or scratching of the head;
detection of lice in hair or folds of clothing;
detection of spots in the affected area.

It is necessary to urgently or independently get rid of parasites, consult your doctor in order to correctly select the method of treatment and the necessary medicinal drug.

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Stages and terms of development

The development process of young lice, which is divided into several different stages, requires a more detailed consideration:

The average time for nit development is from 5 to 8 days. A young insect can only gnaw a hole in the nit, but it will be able to get out, but it carries out respiratory processes, then releasing the absorbed air through its own anus. In the opposite part of the nit, air gradually accumulates and at one moment its excess pushes the insect out, after which it is able to move and actively feed.
The released larva takes 1 to 3 days to transform and become a first instar nymph.
It will take about 5 days for the insect to further develop, after which it becomes a nymph of the second instar.
The second instar nymph needs approximately 8 days to develop, after which it becomes a full-fledged adult.

How long can a parasite live, and how many days do lice hatch from nits?

The development cycle of lice is almost the same. Initially, after 6-8 days, small individuals hatch from the nits, which will feed on human blood. Then every five days they molt. This process is repeated three times. After the third time, the larva becomes an adult.

It can take 2-4 weeks from the moment the nit is born until the adult louse is killed. This is the lifespan of an infectious parasite. With each oviposition, the female is capable of laying 6-14 eggs at a time. Two weeks after emergence, the larva can reproduce.

Incubation period

The development time of nits and the larvae hatched from them does not have any fixed parameters; the duration of the incubation period is a variable characteristic, which largely depends on the conditions in which the insects exist. Taking this factor into account, it is necessary to indicate the following features of this period:

Temperature is one of the main criteria on which the duration of the incubation period and the timing of larval development depend. If an infected person or animal spends a significant amount of time in cool places, the development of insects is greatly slowed down.
Temperatures in the range of +25-30°C are ideal for lice; in such conditions, the development time of nits is minimized and is usually no more than 5 days.
If the temperature drops and is stably maintained at +20°C or lower, then the development of nits not only slows down, but also stops, and the larvae do not hatch.
There are varieties of pubic and body lice; they do not have significant fundamental differences from the usual type of parasites, but their incubation period in some situations can be increased to two months if the conditions are unsuitable.

Description of adults

An adult louse is a small insect whose body length is 0.4–6 mm, depending on the species, so some can only be seen under a microscope. The chest and head of the parasite, clearly separated from each other, are several times smaller than the voluminous abdomen. It is large in size because it acts as a kind of tank for drunk blood. After feeding, the louse visually increases in size.

Lice have wings. True, they are reduced (they are too small to fly). Scientists believe that this happened due to a change in the lifestyle of insects to a parasitic one during evolution.

The insect's mouthparts meet the needs of its lifestyle: it is of the piercing-sucking type. The base is a tube, at the outer end of which there are hooks that cling to the victim’s skin for stability and tight contact. It contains two sharp stilettos in the form of needles. When the insect is not feeding, it retracts the proboscis into the head capsule. Nature has also taken care of the interesting function of the anterior section of the louse's esophagus: when feeding, it contracts and expands, acting as a pump. Thanks to this, the insect sucks in blood.

Insects do not have visual organs, although in some species they are replaced by pigment spots. Lice do not need eyes: they navigate in space with the help of short antennae. They capture odors, performing an olfactory function.

Lifestyle

The louse spends almost its entire life on the body of one owner, only in emergency cases looking for a new victim. The average lifespan of lice is 38 days. The insect is very sensitive to environmental conditions:

The optimal temperature for the life of lice is 30 °C.
If the thermometer drops to 20 °C, then they stop reproducing, and at -5 °C individuals begin to die.
If the temperature rises to 50 °C, the insect will die within half an hour.
Parasites prefer high humidity - about 80%.

You should also pay attention to the question that interests many, how long lice live outside humans. Having lost its food source, the insect soon dies: this usually takes 2 days, although the most tenacious individuals can survive up to 10 days.

On the human body, lice choose the warmest and most secluded places. The linen variety is usually hidden in the neck or armpits, and the head variety is usually hidden in the back of the head and behind the ears.

The head louse lives exclusively on the scalp and never moves to other parts of the body. This feature is associated with the structure of its legs. They are only suitable for moving through hair with a circular cross-section. If you look at the cut of the hair growing on the body, it will be triangular.

Its closest relative is the body louse or linen louse. It moves onto the human body only during feeding. The rest of its life and egg laying takes place in clothes, which is why the variety got its name. None of the species of lice that live on humans live in bedding, towels or other household items. They can leave their owner only through negligence. If the parasite does not soon find a new suitable victim, it dies.

Reproduction

The life cycle of a louse, despite its short duration, is quite interesting. Insects are characterized by sexual reproduction, which occurs in three stages:

Mating of a male and female. The female is ready to have a relationship with the males already 2 hours after emerging from the larva.
Fertilization of eggs. These parasites have an extremely curious feature: the female only needs to meet the male once so that she can then lay eggs. The seminal fluid is stored inside its abdomen. Therefore, despite the short lifespan of lice, their number on the body of the host is rapidly increasing.
Laying eggs, the common name for which is nits. Depending on the species, the female lays a clutch either in the victim’s hair or in the folds of his underwear.

Procreation of the species requires the females to actively feed on blood. Reproduction is not possible if the ambient temperature is less than 21 °C and higher than 37 °C. The development period of the embryos inside the eggs also depends on this indicator. If it is about 36 °C, then the larvae will be born in 4–8 days. When temperatures remain around 23°C, the development process can take up to 16 days. When the temperature drops to 22 °C and rises to 40 °C, the eggs do not hatch.

The vitality of the lice population is also explained by the number of eggs the louse lays: from several dozen to several hundred in prolific species.

Nutrition

Lice are insects with an intensive feeding regime. In 24 hours they “feed” more than 10 times, and for each “meal” the individual absorbs approximately 0.5 ml of blood. The process of blood sucking, made possible by the special structure of the oral apparatus, takes place in several stages:

From the proboscis, located at the end of the head of the louse, two sharp stilettos appear in the form of needles, which pierce the top layer of skin. Such knives are modified parts of the lower lip and upper jaw.
From the fold that surrounds the proboscis tube, when it is everted, hook-like processes appear. With their help, the insect's mouthparts tightly adhere to the skin of the victim.
Through the hole made, the louse injects saliva into the skin, which is produced in abundance by the glands. It contains coagulants, when administered, the blood stops clotting and, therefore, the wound does not heal.
By alternating contraction and expansion of the esophageal tube, blood is drawn from the capillaries into the abdomen of the insect.

The only substance suitable for feeding lice is the blood of warm-blooded animals. Their oral apparatus cannot swallow any other organic parts of the body - for example, hair or dead skin flakes. But the closest relatives of lice are capable of this: lice eaters and lice eaters, which sometimes causes confusion.

How does infection occur?

Methods of infection interest people much more than the processes of lice reproduction. In this case, places with significant concentrations of people in a limited area are potentially dangerous, especially if there is a violation of sanitary standards in them, first of all, these include:

Communal apartments.
Various hostels.
Children's preschool and educational institutions.
Camps and other recreational places.

Direct infection with pediculosis can occur in the following ways:

Close contact and contact between an infected and healthy person. It is worth noting that when communicating at a distance, infection is impossible, since lice cannot jump or fly. However, these are very fast insects, so in most cases a very short and insignificant close contact is enough for the parasite to move unnoticed onto a healthy person.
Another common method of infection is the use of the same personal hygiene products by a healthy and infected person , especially those that come into contact with hair.
If you sleep in the bed or wear clothes of an infected person, there is also a high risk of infection.
Infection through water, for example, in public baths or ponds.

History of neighborhood with lice

The origin of lice is inextricably linked with the history of mankind. They constantly accompanied people. At the same time, attitudes towards parasites have changed throughout history. If now they cause disgust and association with social ill-being, then several centuries ago the attitude towards these blood-sucking insects was much more loyal. Recognition of their danger was facilitated by the massive loss of life due to typhus epidemics.

According to Slavic beliefs, seeing lice on your body in a dream means money. Moreover, the more parasites there are, the more wealth a person will receive.

Ideas about lice that were quite wild for modern people to understand existed in the Middle Ages in Europe. The insect was called "God's pearl" because it contained "Christian blood" in its abdomen. Being the owner of parasites was considered good manners, and not washing throughout one’s life was considered a sign of holiness and good behavior. All this, of course, contributed to the widespread infestation of lice. The poet from Italy Giambattista Marino, in his love lyrics, reverently sang the insects that live in the blonde locks of his lady love.

How quickly do parasites become active?

The rate of manifestation of parasite activity depends on the method in which a person became infected:

If an adult insect comes into contact with a healthy person, it will become active in the very near future . This is due to the need for frequent meals, which is blood. The parasite feeds once every few hours; without food, it usually dies within two days. Pubic lice are even less hardy; if there is no food or the inability to eat, they die after about 10 hours.
If an infestation with nits occurs, the first activity will occur after 5–8 days , since the insect does not have the opportunity to feed until it hatches.
It is worth noting that people often do not notice the activity of parasites immediately, but only after 1–1.5 months. This is due to the fact that the bites of one or even several insects are insignificant or barely noticeable, but within a few months their population increases significantly and the bites of a large number of parasites are already well felt. From this moment on, all the symptoms and consequences of lice appear.

What determines the duration of treatment?

Therapeutic therapy for pediculosis consists of the use of complex measures that are aimed at achieving the main goals. First of all, the attack of funds is aimed at destroying rot eggs and adults. Then the fight is to eliminate itching and skin rashes. The complexity of effective therapy depends on a number of significant factors:

Age category of a person . Children are the most difficult to treat. It is not always possible to use a potent drug here. In addition, children's skin is too vulnerable.
Stage of illness . If there are a lot of rot eggs on the hair, the therapy will be long. Treatment should always begin as soon as the first signs are discovered. Do a preventive examination.
The presence of various complications . The saliva of parasites can provoke the development of allergies, the formation of ulcers, and streptoderma.

How to notice the first signs in time

When infected with nits, it is quite difficult to notice the first signs in a timely manner, since they usually do not show activity during the first days. Sometimes people do not immediately notice adult parasites in themselves if their number is small, but this is quite possible. The main signs of lice are:

Tingling and itching. The tingling sensation is reminiscent of mosquito bites; these sensations arise due to the fact that lice pierce the skin, since in this way they need to get to their main food - human blood. Itching and burning occur due to the fact that the parasites secrete a special substance and moisten the fresh wound with it; it does not allow the blood to clot. Itching caused by insects is easy to identify: it does not go away even after washing your hair and most often torments at night.
Itching in the area near the genitals or armpits is a much more clear indication of the presence of pubic lice, since the head in some cases can itch for other reasons, for example, due to nervous disorders.
Frequent and causeless crying of a baby, as well as his sudden increased moodiness, may also be evidence that he is being bitten by lice.
Detection of nits on the hair, they can be identified using a normal visual inspection.

If you ignore all the signs of lice and do not deal with this problem, this can lead to the most serious problems: enlarged lymph nodes, rotting of wounds and scalp, a large number of abrasions and scratches, hair rolling into tangles and many others.

Frequently asked questions from our readers

Expert opinion

Alexandra Valerievna

Doctor-Trichologist

If nits click, does that mean they are alive?

Living nits, when pressed with your fingers or nails, make a characteristic click, as if a soap bubble is bursting. The sound of this click is quite loud and strong. If the nit is dead, then it will not make any sound, no matter how hard you press and squeeze it. If it makes any sound, it means that it is still alive and it is necessary to take repeated measures to remove them.

How not to confuse nits with regular dandruff?

The most popular method is visual analysis of the “crumbs” that you have discovered. The skin scale, unlike the nit shell, is less dense to the touch and it does not separate, while the egg is dense and clicks when you press it. Nits are also distinguished by their excessive yellowness from ordinary dandruff.

Is there a risk of getting lice and nits again?

There is, of course, such a risk, since even if you try to maintain a certain good level of hygiene, do not use shared objects and do not swim in public places, a carrier person with whom you have had close contact and whose lice really liked you.

Basic ways to combat head lice

Among the people, before the advent of modern medicine, the prevention of pediculosis was carried out by shaving the hair to zero; in our time, cutting one's head is also sometimes practiced, but thanks to modern medicine, the main ways to combat pediculosis are:

Pharmacy products

Of all the pharmaceutical drugs, the most suitable, effective and safe means are Medifox and Paranit . These two drugs do not contain harmful chemicals; they gently remove parasites from their location, without side effects. Also, these two drugs are perfect for children, since they have minimal toxicity and, consider, almost no side effects. Also, tablets are used to get rid of head lice. After the human carrier begins to take the pills, the lice, having sucked on the blood, die.

Shampoos

Shampoo can also be used as a means to combat lice and nits, but most often it is used after the destruction of parasites, as a preventive measure and to remove the shells of dead pests from the wearer’s head. A good example would be Pedilin. This shampoo can be used by both children and adults without worrying that it will harm them in any way. A course of treatment for head lice with shampoo lasts at least three days to completely eliminate the likelihood of recurrence of the disease. When washing your hair, you need to place a disposable towel or napkin on your shoulders and then dispose of them.

Sprays

Another effective remedy against lice and nits can be a spray, for example, Nyuda or Para Plus. These sprays are suitable for both adults and children, as they do not contain toxic substances that could harm health or cause side effects on the body.

Scallop

The comb is more suitable for removing already killed parasites from the hair of a human carrier, but it is also sometimes used to remove still living individuals from the scalp. Most often, the comb is sold complete with a preparation against lice and nits. Initially, an anti-parasitic agent is applied, which will kill all lice and nits, or at least most of them, and then they are removed from the hair with a comb. If you do not remove the dry shells remaining from nits and lice from your hair, a burning sensation on the scalp may occur and scabies (itching) may begin, since the shells of the parasites are somewhat toxic and release their poison.

Folk remedies

You can also get rid of parasites using folk remedies, but this will not be as effective as medical means , and lice and nits will not be removed from the human carrier in one procedure. There are a variety of folk remedies for lice and nits. Some people shave their heads when parasites appear, others prefer to use kerosene, tar and laundry soap, vinegar or lemon juice and much more, using home remedies and treatment methods, it is worth remembering that some of them can cause an allergic reaction or a chemical burn (kerosene , vinegar, dichlorvos).

REFERENCE! It is worth giving preference to medical products that will be more effective in treating head lice.

Prevention

In order to avoid having to treat pediculosis, remove lice, and also suffer from not the most pleasant symptoms of this disease, it is recommended to take preventive measures that can help protect against the possible occurrence of these parasites. Such protective measures include:

Compliance with personal hygiene rules, taking a shower and washing your hair should be done at least twice a week.
Change your underwear periodically: both underwear and bed linen.
Wash linen and other clothes at high temperature, then iron. Particular attention must be paid when ironing seams and other hard-to-reach places.
Lubricate the back of the head and ears with various protective agents that can repel parasites. Tea tree extract or lavender oil are best suited for this.
Have individual personal hygiene products, such as a towel, comb, hairpins, hair ties, headbands. You should not let other people use them, nor should you take someone else’s equipment.
Do not wear other people's hats and do not give yours to anyone.

Children require special attention in this case, since due to their age and lack of understanding of the seriousness of the situation, they may neglect some rules of personal hygiene. A child is already susceptible to the risk of infection during contact games or communicating with peers at school; often the use of other people’s hairpins or wearing hats is artificially added to the risk factor. A child who has picked up lice can infect the entire family on the same day.