Incubation period of development of head lice

Head lice - parasites are very highly specialized, not only in the nature of food, but in the place of its existence. They can live only on the scalp of the head of a person and of his closest relatives - some species of monkeys. Accordingly, the life cycle and features of biology, including the incubation period of head lice, are largely adapted and depend on the lifestyle of the person himself.

On a note

It should immediately determine the terms. Under the incubation period of any disease usually understand the period between infection with it and the first clinical manifestations. This definition is not suitable for infecting a person with head lice - parasites will start to bite a person immediately after infection, but due to the small number of them, the patient may not feel it or give importance to certain unpleasant sensations.

The incubation period for lice in biology is the time for the development of louse eggs. Considering the fact that louse eggs are called nits, for an entomologist the incubation period for lice and nits is essentially the same. Taking into account the fact that many readers regard lice as a disease, when describing the incubation period of lice, we will further consider it in the biological and, so to speak, in the popular sense.

 

Incubation period for lice: how quickly they begin to pester after infection

After infection, the first bites of lice occur already in the first hours after the parasites hit the human hairline - these insects cannot live without food for more than a few days. However, the bites of one or two individuals who managed to crawl on a healthy person are not particularly felt and often do not pay attention to themselves. Therefore, at this time, it is too early to talk about any manifestations of pediculosis.

Real symptoms of lice on the head begin to be felt after three or four weeks. During this time, the nymphs of the first generation, who are already massively biting the human scalp, have time to grow out and grow up.

Under favorable conditions, after three weeks, the second generation of lice appears on the head, and thanks to a large number, they already cause severe itching and well-marked discomfort.

On a note

Pediculosis is a complex of symptoms characteristic of people with severe lice infestation. In medical practice, pediculosis is considered a disease and manifests itself in the form of heterogeneous symptoms caused by the activity of lice: itching, abscesses, the appearance of spots and allergic rashes.

Thus, in this case, such an incubation period for lice can be considered to be equal to three weeks. It is during this period that all signs of lice appear on the head: nits, irritation, itching, and the possibility of infecting other people.

It is interesting

Depending on the human living conditions, the incubation period for the development of lice may vary. For example, in conditions of winter or northern latitudes, when a person’s head is constantly covered with a hat, and indoors is sufficiently heated, lice develop faster — sometimes in 16 days the full cycle of their reproduction takes place. In mid-latitudes, when the head of a person is often open, parasites usually develop longer.

 

Reproduction of lice: in detail about nits and nymphs

Head louse - an insect with an incomplete transformation. A larva hatches from its egg, resembling an adult, but much smaller and not capable of reproduction.It feeds on the same as adult insects feed on - with human blood - sheds three times and turns into an adult insect.

On a note

Do not confuse the concept of "nit" and "egg louse." Nit is the formation of an egg and a cocoon of a sticky substance that holds the structure on the hair. We can say that this is a kind of cocoon.

Such a larva, which is generally similar to an adult insect, is called a nymph. Stage nymph is also characteristic of other insects, - for example, for cockroaches, grasshoppers and bedbugs.

It is important that each stage of development in lice lasts a relatively short time, and therefore the lifetimes of these insects are small, and the reproduction rate is quite large. In parasitologists, it is customary to call an insect that has just emerged from an egg, a larva, and a molting larva, a nymph.

 

Reproduction dates and incubation period for lice

Terms of development of lice at each stage are different:

1. The maturation period of nits is 5 to 8 days, depending on the temperature. Optimum conditions for nits that ensure the minimum incubation period for nits is the average air humidity and temperature of about 31 ° C.At temperatures above 40 ° C and below 22 ° C, the development of eggs stops, and the larvae do not hatch.
2. The larva of the first age develops from one day at a temperature of 30 ° С to ten days at a temperature of 10 ° С.
3. The nymph of the first age develops 5 days.
4. The nymph of the second age develops eight days and turns into an adult - an adult insect.
5. Adult insects begin to multiply after the first meal after shedding. Usually, females and males mate for 1-2 days after the nymph is transformed into an adult insect, after which females lay 3-4 eggs every day.

How long the lice hatch from eggs is greatly affected by temperature. At 25-26 ° С, lice hatch in 7-8 days, and at 32-33 ° С - in 5-6 days.

How quickly the lice hatch does not depend on how often the head is washed or the hair gets wet.

On how many nits ripen, depends on the time of the total reproductive cycle of insects. The minimum development time from egg to egg is 16 days, the maximum can stretch up to two months.

On a note

Head lice have almost no hunger strike periods. They constantly live on the scalp, never leaving the human body.Therefore, factors such as the presence or absence of food, there is practically no in the life of these parasites.

The maximum lifespan of an adult head louse is 46 days. During this time, the female has time to lay up to 140 eggs.

 

And what about other species?

The incubation period for lice of other species differs little from that of a head louse.

So, in a clothes louse belonging to the same species, but adapted to life on clothes, nymphs hatch in 5-8 days. And the average time of development is 3-4 weeks - as in head lice.

On a note

Sometimes the expression “hatch nits” is used in principle is incorrect. Lice hatch nymphs, and the nits themselves are laid by the female. Therefore, instead of "nits hatch" should say "the larvae hatch from nits."

The incubation period of pubic lice is approximately 6 days, and the period of development of the larva is about 18 days. Their difference from head lice is that an adult pubic louse lives no more than 30 days, and one female can lay a maximum of 50 eggs.

In pubic lice, the larvae from nits do not hatch at temperatures below 22 ° C.

 

Methods of dealing with nits

Destroy and poison nits is quite possible and even necessary at any stage of their development.To do this, usually used special shampoos with effective insecticides - Pedilin, Parazidoz, Nittifor, Pedeks, Hygia. Previously, even kerosene was used against lice, but in terms of efficiency and ease of use, of course, it is significantly inferior to modern shampoos.

It is important that even after a haircut, it is necessary to wash the head with shampoo and hold it under a plastic bag, since the lice themselves can sit on the skin and near the hair follicles. And when using a shampoo that does not have the ability to kill the eggs of lice - you need to wash their head again after 5-6 days.

And of course, always and everywhere it is necessary to follow the rules of hygiene: do not wipe yourself with someone else's towel, do not use someone else's comb. It is known that head lice can survive in the water for two days, so even swimming in public places can be fraught.

Be carefull!

 

Useful video: about the development of lice and how to deal with them