Types of lice, generally speaking, are numerous - only in mammals there are more than 500 species of these insects. In this case, only two different types of lice are parasitized on a human: the human louse (Pediculus humanus) and the pubic louse (Pthirus pubis). They quite easily differ from each other both externally and by their habitats and parasites.
It is often incorrectly considered that there are not two types of lice in a person, but three: for example, head and lice are also differentiated. However, these are not separate species, but only forms (scientists call them morphotypes) of human lice, peculiar varieties of lice. They are adapted to live in different conditions: the head - in the hair of the head, and the clothes (linen) - on the clothes - and during the time of parasitism on the person managed to develop such differences in the way of life that on the human body they practically never intersect and interbreed. Laboratory studies have shown that before their complete separation into different species has not yet reached, and when they exist together (possible only in artificially created conditions) they are able to interbreed and give fertile offspring.
The photo below shows different types of lice in humans - human and pubic:
And on the next photo - a variety of lice in humans. The first is the head louse, the second is the louse:
On a note
No matter how numerous lice are in nature as a whole, their species are specific in that they are adapted to life only on one species of the host animal. Thus, human lice can not live on the body of other mammals, except for a few species of monkeys, and dog lice live only on dogs - and so on.
That is, a man can get infected with lice only from another person, but not from animals. In this respect, lice are significantly different from fleas. The latter have similar dimensions, but can parasitize on a large number of species of host animals.
All varieties of lice in humans are similar in that the full cycle of their reproduction takes place on the host's body or in close proximity to him - on hair or clothes. All types of lice that occur in humans are exclusively blood-eaten, and unlike other parasites, each individual bites the victim several times a day - most blood-sucking insects are left with food every few days (for example, bed bugs) or even weeks.
The head louse is the most common parasite and is often found even in people living in normal sanitary conditions. This insect infects only the scalp, only in extremely rare cases moving in men to whiskers and beard.
In general, this species of lice differs from the dressing body by a slightly darker color of the body - it is grayish-brown. After feeding, the body color of the insect becomes darker than it was before, due to a droplet of blood in the stomach. The photographs below show several insects of this form:
The main difference between head lice and underwear is the difference in their habitats.
The size of adult head lice is about 2-4 mm. Lice of lice are about 0.6-2 mm in size. Eggs of head lice are called nits and firmly attached by the female laying them to the hairs at a distance of about 2-3 cm from the surface of the scalp.
Head lice multiply constantly regardless of the season. They feel great at a temperature of 30-33 ° C, and continue to multiply in the temperature range from 23 ° C to 40 ° C. Lice bend when the temperature falls below 0 ° C or rise above 45 ° C.
Without hair on the head, this species of lice can not live. In the picture below - a louse crawling along a bunch of hair:
Accordingly, the most simple and reliable way to bring your head lice is a haircut "naked." In other cases, you should use shampoos, sprays or creams containing insecticides, or special hard and thick crests from lice and nits.
The louse (also known as the linen louse) is very similar in appearance to the head louse and has a similar body structure with an elongated abdomen, as well as similar dimensions. It differs from the head louse with the color of the body - it is usually white or light gray with a yellowish tint, and, of course, habitats.
The louse is adapted to life only on clothes constantly or very often located on the human body. To live on hair or in clothes which the person puts on very rarely, she can not. Therefore, most often the victims of lice are vagrants, refugees and antisocial personalities who do not change the wardrobe and rarely wash clothes.
Below in the photo this species of lice is presented - the parasite accumulation on the tissue is evident:
The louse lures a person under the clothes and in most cases - on the hairless sections of the body.
These parasites lay their eggs (nits) on clothes, and therefore fighting with them is usually more simple than removing head lice: here you either need to boil, or treat things that are dangerous for your lice, and wash your body thoroughly to simply wash away the remaining ones of insects.
On a note
All lice can withstand a prolonged immersion in water. When washing the head and hair in the groin area, the lice that have grasped the hair are not washed away, and even more so, the nits remain unharmed. Only individuals can be washed away, which were then on the skin.
Of all varieties of lice in a man, pubic louse is the smallest. The adult specimen reaches a length of no more than 2 mm, and larvae of the first age - only about 0.5 mm. Without a microscope, these insects are similar to small brownish points slightly flattened.
Pubic lice infect almost exclusively the scalp in the groin, but in very rare cases they can settle in the armpits, and in some cases (especially when infecting the water) on the eyebrows and eyelashes:
Under the microscope, the difference in the form of the body of the pubic lice from the human lice (head and body) is clearly visible - the parasite is considerably shorter and has legs that are more massive in relation to the body size. In the photo below, both types of lice are seen at high magnification:
Pubic lice are transmitted most often during sexual intercourse, and therefore infection is considered a kind of venereal parasitosis. However, in some cases pubic lice are transmitted through water or when using common clothing.
It is interesting
Experts note in recent years a decrease in the infestation of pubic lice and the reduction in the number of this parasite in general. It is believed that one of the reasons for this - the fashion for shaved pubes, because of which insects are deprived of the only suitable conditions for their existence.
Lice in other animals
In other animals, lice are much more different in size and body shape.
- Hare louse, covered with hairs and very dense body. It parasitizes several species of rabbits and rabbits.
- Pork louse, large enough and having a body length of about 5 mm. She sits behind the ears, on the folds of the neck, belly and legs of domestic pigs and wild boars.
- Dog's louse, belonging to the order of swearing. In addition to the host's blood, it can also eat pieces of skin and secretions of the skin glands of the animal.
- The elephant louse, adapted to the lack of hair on the owner of the fact that it has a widening end of the proboscis, due to which it bites firmly on the skin when bitten.
The photo below shows some of these types of lice. All species that live on animals are not dangerous to humans:
In addition to the lice proper, vermiles are also very well known in animals. They number more than 3,000 species, and they lead a lifestyles similar to lice. Their main difference from true lice is the ability to eat not only blood, but also various derivatives of the skin of the host. Even more numerous puhoedy in birds, but they are distinguished from lice even more features.
Considering what kind of lice are, it is impossible not to remember about the famous book louse.
It is not a typical louse, but refers to the suborder of the senoids and feeds on various organic remains: from various groceries to book bindings. It is not dangerous for a person.
Getting rid of lice and nits at home for 1 procedure: