Pediculus Humanus Humanus, Capitis, Rporis: Appearance And Structure

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Pediculus Humanus Humanus, Capitis, Rporis: Appearance And Structure
Pediculus Humanus Humanus, Capitis, Rporis: Appearance And Structure
Video: Pediculus Humanus Humanus, Capitis, Rporis: Appearance And Structure
Video: Pediculosis | Pediculus humanus | Structure, Life cycle, Transmission | Head lice and body lice 2023, February
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  • Morphology
  • Lice-borne diseases
  • Ways of infestation with head lice
  • Symptoms of Pediculus humanus humanus infection
  • How to correctly diagnose a parasitic skin disease?
  • What are the most effective home treatments?

    • General recommendations for the treatment of affected skin areas
    • Use of pediculicidal agents
  • You can defeat parasites!

The body louse (Pediculus humanus humanus) is a synanthropic species, a human parasite. Lives in the folds of linen and dresses. At all stages of post-egg development - hematophagus. Reproduction is bisexual.

Development is incomplete. The lifespan of an adult is 32–46 days. The development of one generation is 16 days.

What to do in such a situation? To get started, we recommend reading this article. This article details the methods of dealing with parasites. We also recommend contacting a specialist. Read the article >>>

Morphology

Imago. Small insect (2.1-4.7 mm). The body is wingless, dorsoventrally compressed. The oral apparatus is piercing and sucking, at rest is hidden inside the head. Antennae are long. The chest is solid, it is not clearly dissected into segments. Legs are grasping. Chest with dorsal fossa and sternal plates. Legs of equal size with thin claws. The pleural plates of the V – VIII segments do not extend into the intersegmental notches.

Pediculus humanus humanus
Pediculus humanus humanus
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Sexual dimorphism. Different-sex individuals differ in the structure of the genitals.

Male. The body length is 2.1–3.7 mm. Like the entire order of lice, the fore tibia has a finger-like outgrowth with which the male holds the female during copulation. The posterior end of the abdomen is rounded, and the copulatory apparatus is located on the last segment on the dorsal side.

The female. The body length is 2.2–4.7 mm. The ventral longitudinal muscles are usually located on the IV segment. The genital plates of the female are large, with a deep anteroposterior notch. Gonapophyses narrow. Like all lice, there is a blunt spur at the base of the thighs of the third pair of legs.

The egg (nit) has an irregular, ovoid body, one end of which is pointed, and the other is covered with a lid. Length - 0.9 mm. The lid is flat, with low valves pushed aside. The eggs are glued to a group of hairs or tissue.

The larva, nymph I, nymph II differ from the adult insect in size and the absence of external genital organs.

Imago is a permanent human parasite. It feeds on blood. The feeding mechanism is the same as that of the head louse (Pediculus humanus capitis). Lives in the folds of linen, especially in the seams. Average lifespan is 34 days, minimum 32 days, maximum 46 days.

The optimum temperature for development is from +30 to + 32 ° С. Adult lice eat 2 to 8 times a day. To feed, lice crawl from clothing to the surface of the human body. The mobility of the pest depends on the ambient temperature. At + 25–27 ° С, mobility is increased, and at + 5 ° С it disappears. The movement speed of lice is from 10 to 35 cm per minute. With a high degree of lice, insects can be found on the bed, on the floor, on clothes. Lice can spread with the flow of water in streams and rivers when people swim in mass. They remain alive in water for about two days.

Mating period. The first oviposition occurs 24–48 hours after the last larva molt. Females lay about 10 eggs daily, over a lifetime - from 200 to 300 eggs. The eggs stick to a group of hairs or tissue.

Egg (nit). Embryonic development lasts 5–8 days. As with all lice, the optimum temperature for egg development is + 30–31 ° C. At temperatures below + 22 ° C and above + 40–45 ° C, larvae do not hatch.

Egg (nit)
Egg (nit)
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Larva. The hatching of the larva proceeds in the same way as in the head lice (Pediculus humanus capitis). After hatching, the larvae suck blood, and after a few days they molt and turn into nymph I. At a temperature of + 28-30 ° C this happens every other day, at + 10-20 ° C - after seven days, and at + 9-10 ° C - in ten.

General information. All stages of development of Pediculus humanus humanus, including nits (eggs), are very sensitive to temperatures above + 37 ° C. Lice tolerate dry heat + 47–50 ° C only for 10 minutes. A drop in temperature to –13 ° C causes the death of insects after 7 days.

Lice-borne diseases

Lice bring a lot of inconvenience to the patient. To get to the capillary, lice bite through the upper layer of the epithelium and inject a special enzyme that prevents blood from clotting. This substance is irritating to the skin.

As a result, the person feels itching, scratches the bite and damages the skin. Further, a number of consequences arise, which progresses rapidly if treatment is not started:

  • combs turn into wounds and ulcers, the skin gradually begins to peel off;
  • hair becomes dull, loses its aesthetic qualities;
  • the resulting injuries serve as an entrance gate for pyogenic microflora;
  • secondary infection leads to inflammation of the lymph nodes in the neck and the area behind the ears;
  • with prolonged absence of treatment, an abscess occurs;
  • further development of the disease leads to pyoderma (purulent skin lesions);
  • a person loses peace, becomes irritable, nervous, constantly in a bad mood, does not sleep well;
  • the body's immunity weakens, which leads to the occurrence of other diseases.

In addition, in rare cases, lice can become carriers of some serious diseases:

  • relapsing fever,
  • typhus,
  • quintan,
  • tularemia.
Lice-borne diseases
Lice-borne diseases
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Ways of infestation with head lice

Head lice can be caught by anyone, regardless of gender, age, race or nationality. The social status of the infected does not matter. But still, a certain group of people can be identified who are most likely to get sick.

  • people in prison;
  • people without a fixed place of residence;
  • people leading a wandering lifestyle;
  • refugees;
  • residents of zones of armed conflict;
  • military men who have been in barracks and training grounds for a long time;
  • tourists staying in hotels with a dubious reputation;
  • hairdressers;
  • children (mostly girls) attending children's educational institutions, sanatoriums and camps.

There are two ways of infesting head lice:

  1. Contact with a person already suffering from head lice. In the case of head lice, contact means being close to the infected person's hair. For example, during a hug, a close touch on public transport, or a group selfie. With a normal handshake, head lice are not transmitted, body lice can.
  2. Contact with this person's things. If you have combed your hair with a comb or a sick person's brush, slept on his pillow or bed, put on his hat, etc., the infection is likely to occur.

Toddlers are reckless and careless, they often hug, exchange toys and accidentally get infected. Teenagers who often spend the night with each other, exchange clothes, hats, share hairpins and hair ties, and kiss are no more careful.

Symptoms of Pediculus humanus humanus infection

Signs of pediculosis infection include the following facts:

  • detection of lice and nits;
  • severe itching on the scalp;
  • the appearance of combs and other damage in places of possible localization of parasites;
  • presence of bite marks;
  • pyoderma (purulent inflammation of the skin);
  • the formation of hair tangles.
Symptoms of Pediculus humanus humanus infection
Symptoms of Pediculus humanus humanus infection
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How to correctly diagnose a parasitic skin disease?

To identify the first symptoms of head lice, it is enough to part the hair on the head and examine it in good light. Visual inspection will determine the presence of nits and parasites.

Secondary symptoms of the disease are scratching of the skin, as well as sticky hair. If, upon examination, only a single individual without nits is found, pediculosis is still diagnosed.

What are the most effective home treatments?

Pediculosis can be treated at home, but you need to decide on a way to fight parasites. On the pharmaceutical market there is a large assortment of shampoos and preparations that effectively fight lice. With self-treatment it is necessary:

  • isolate the patient during treatment;
  • choose an acceptable remedy (folk or from a pharmacy);
  • carefully study the method of application and instructions;
  • adhere to dosages for children and adults;
  • use the drug carefully, avoiding contact with the eyes;
  • rinse thoroughly from hair.

General recommendations for the treatment of affected skin areas

Any remedy against Pediculus humanus humanus requires careful use - the composition contains insecticides with a very pungent odor. It is important to observe the concentration of the drug. Children under 2 years of age and pregnant women should be prescribed treatment by a doctor. Treatment of the affected areas is carried out following certain rules:

  • conduct an allergy test (apply a little product on the wrist, check after 2 hours for irritation);
  • the procedure must be carried out in a ventilated area;
  • distribute the composition along the entire length of the hair, excluding contact with the eyes and on open skin areas (it is better to use a protective visor);
  • put a plastic bag cap on your head in order to create the conditions for a greenhouse;
  • withstand the required time;
  • wash off the mixture and rinse your hair with a vinegar solution;
  • take a fine-toothed comb and comb out your hair in order to get rid of dead parasites.

Use of pediculicidal agents

Detected head lice requires immediate treatment, as it rapidly progresses and is transmitted to others. To combat lice, drugs from a pharmacy based on insecticides or enveloping compositions are suitable: shampoos, gels, aerosols, ointments, sprays.

Chemicals affect the nervous system of parasites, causing their death. Pediculocides are allowed to be used by patients from 2 years old. The composition of drugs may contain the following substances:

  • fenthion;
  • malathion;
  • permethrin;
  • pyrethroids.

More safe for humans drugs based on cyclomethicone or dimethicone. After application to the hair, the active substances of pediculocidal agents block insects' access to oxygen, creating a thin airtight film around them.

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