Leishmania Braziliensis: Life Cycle, Symptoms And Treatment

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Leishmania Braziliensis: Life Cycle, Symptoms And Treatment
Leishmania Braziliensis: Life Cycle, Symptoms And Treatment

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Video: Leishmania donovani Lifecycle ( English ) | Kala-azar | Dumdum fever 2023, February
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  • The structure of Leishmania braziliensis

    Cultivation

  • Life cycle
  • Infection routes
  • Varieties
  • Leishmania braziliensis symptoms

    • Visceral leishmaniasis
    • Cutaneous leishmaniasis
    • Mucosal leishmaniasis
  • You can defeat parasites!

Leishmaniasis is a group of protozoal infections, manifested by intoxication, fever, lesions of the visceral organs or integumentary tissues. The causative agents are protozoa of the genus Leishmania braziliensis; all its species are obligate intracellular parasites of mammals.

For the first time the causative agent was discovered by W. Leysch-man (1900); in honor of him, the parasites got their name. Traditionally, four types of leishmaniasis are distinguished: visceral (kala-azar), cutaneous of the Old World, cutaneous of the New World, and mucocutaneous. Each type is defined clinically and geographically; etiological agents are morphologically identical, the transmission of the pathogen is carried out by various types of mosquitoes.

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 >>>

Leishmaniasis is a vector-borne infection. The reservoir of the causative agent of leishmaniasis is infected people and various mammals (dogs, jackals, foxes, rats, etc.); vectors are mosquitoes of the genera Phlebotomus and Luizomyia. After recovery, a lifelong strain-specific immunity develops. When stained according to Romanovsky-Giemsa, the cytoplasm is bluish-lilac, the nucleus and kinetoplast are red-violet. The species of the genus Leishmania braziliensis are morphologically identical in many respects, which complicates their classification. Currently, there are four groups of pathogens.

The structure of Leishmania braziliensis

In its development, Leishmania goes through 2 stages. In the body of a mosquito, parasites are in a flagellated, mobile form (leptomonas form), in mammals - in a flagellate form, intracellularly (leishmanial form).

  • Promastigotes (flagellate forms) are mobile, have a fusiform body from 10 to 20 microns in length. Flagella 15 to 20 μm long. Propagated by longitudinal division.
  • Amastigotes (flagellate forms) have an oval body from 2 to 6 microns in length. 1/3 of the cell volume is occupied by a rounded nucleus. Reproduce by simple division.

Cultivation

Leishmania is easy to grow in the laboratory. In cell cultures, Leishmania have an oval shape, the flagellum is absent (amanzygote). In acellular media, parasites are spindle-shaped and have a flagellum at the anterior end (promastigote).

Leishmania braziliensis
Leishmania braziliensis
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Life cycle

Infection with Leishmania occurs through mosquito bites. Mosquitoes become infected with parasites by sucking the blood of a sick person or animal.

  • In the intestines of a mosquito, already on the first day, amastigotes (flagellate forms) turn into promastigotes (flagellate forms) and begin to divide intensively.
  • On days 6 - 8, a huge number of promastigotes accumulate in the pharynx and proboscis of the insect, blocking the exit to the outside.
  • After the bite, due to blockage of the alimentary canal, the female cannot swallow. She has spastic movements, which contributes to the regurgitation of promastigotes into a wound on the skin (from 100 to 1000 with one bite).
  • After invasion within macrophages, the flagellar forms of Leishmania transform into flagellate forms. The reproduction of parasites is accompanied by an acute inflammatory reaction.
Life cycle
Life cycle
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Infection routes

Carriers of Leishmania are mosquitoes, which become infected when they bite a sick animal or person. That is, if a mosquito that has bitten an infected person bites a healthy person, infection will occur.

The carriers of the simplest microorganisms (Leishmania braziliensis) are called reservoirs. Any vertebrates can be a reservoir, for example, animals - canines (foxes, jackals, dogs), rodents (gerbils, gophers).

Moreover, in the reservoirs of Leishmania they are in an immature flagellated form, then in the throat of a mosquito they pass into an active mobile form. When a mosquito stings a person, mature Leishmania protozoa enter the wound, invade the body and parasitize cells, affecting the skin or internal organs.

Infected mosquitoes remain infectious throughout their lives and can transmit disease to a large number of people and animals.

Infection routes
Infection routes
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Varieties

There are many subspecies of leishmaniasis, depending on the region of distribution. There are three main clinical types:

  • Cutaneous. Also, the disease is called tropical ulcer, rubber ulcer, Aleppo ulcer, Mexican leishmaniasis, Delhi ulcer. In southern European countries, Africa and Asia, cutaneous manifestations are provoked by the species major and tropica Leishmania. Leishmania braziliensis is common in America and Mexico. Often the fact of infection is recorded among residents of Afghanistan or Iraq. Tourists in Israel and South America are exposed to disease.
  • Mucocutaneous. Causes subspecies braziliensis and other types of Leishmania. Parasites invade the lymph nodes.
  • Leishmaniasis of internal organs. Also called kalk-azar, dumdum fever. The causative agent is donovani, infantum / chagasi. This species is found in India, America, Africa, the Mediterranean countries, Central Asia and even China.

Leishmania braziliensis symptoms

The first time after infection, leishmaniasis can go unnoticed, the incubation period, when there are no symptoms, lasts from 3 months to 1 year. It is possible to notice only a boil that occurs at the site of an insect bite. Further, the disease develops depending on the variety. Let's consider them below.

Visceral leishmaniasis

Symptoms of this type occur 3 to 5 months after infection. More often, the disease manifests itself gradually: weakness, general malaise occurs, appetite disappears. Then a fever develops, the temperature rises to 39 - 40 degrees, the fever can subside and reappear. Lymph nodes are enlarged.

But the first sign that appears almost immediately after the bite is a scaly papule.

Varieties
Varieties
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Over time, liver damage becomes critical, up to ascites (effusion in the abdominal cavity). The bone marrow is affected.

More often children are exposed to this form. Due to the enlargement of internal organs, an enlarged abdomen is characteristic.

Cutaneous leishmaniasis

The symptomatology of this variety begins with the primary focus of the lesion - leishmanioma.

It is a specific granuloma on the skin, made up of epithelial cells (connective tissue), plasma cells (which produce antibodies) and lymphocytes (cells of the immune system).

Necrosis (death) of tissues is also possible. Here the incubation period is shorter - from 10 to 40 days. The primary lesion begins to grow rapidly, reaching 1.5 cm.

After a few days, an ulcer with a thin crust appears. Then the crust falls off, exposing the pink bottom of the ulcer.

First, serous fluid is present in the ulcer, then pus appears. After a couple of days, the bottom of the ulcer dries up, the pus goes away, and scarring occurs.

The skin type of the disease is divided into several subspecies:

  1. Consistent form. Many small lesions appear next to the primary granuloma, which go through the stages described above.
  2. Tuberculoid form. Bumps appear around the scar of the primary lesion and even on the scar itself, which increase and merge with each other. Sometimes the bumps break open and turn into ulcers.
  3. Diffuse-infiltrative form. It is characterized by thickening of the skin and infiltrates (accumulation of cells with an admixture of blood and lymph). A significant portion of the skin may be affected. Over time, the infiltrate resolves on its own. With this type, ulcers appear extremely rarely.
  4. Diffuse form. In this form, the disease occurs in people with reduced immunity, for example, HIV-positive. Characterized by the extensive spread of ulcers throughout the body, and this process is chronic.

Mucosal leishmaniasis

This form also occurs in the presence of primary specific granulomas of the skin. First, there are extensive ulcers on the body, often on the arms and legs.

Then the mucous membranes of the nose, cheeks, larynx, pharynx are affected. There necrosis (tissue dies off) and ulcers appear. The lesions destroy the cartilage tissue, so face deformation is possible.

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