Leishmania is a variety of protozoan parasites (protists) that lead to the development of leishmaniasis in humans. About 12 million people from countries with humid and warm climatic conditions are exposed to this disease every year. The distribution area of parasites and their carriers is a tropical and subtropical climate, for example, Afghanistan, Saudi Arabia, Peru, Brazil, Syria, Iran, as well as Ethiopia, Sudan, Nepal and India.
The structure of Leishmania
What are the features of pathogens? Leishmania disease has two main morphological forms - amastigotes and promastigotes, which have a distinctive structure and different features of the development and distribution cycle. Amastigota is the initial stage of development of the microorganism. Such a Leishmanic form of infection at the initial stage of its development has a rounded shape. Microorganisms are easily detected under a microscope when examining biological material taken from a patient in a laboratory. For this, doctors take epithelial cells. Most often, it is the amastigote that can be seen in the photo of Leishmania, as in the picture below.
Promastigota is a leptomonas form of the microorganism. The structure of Leishmania is characterized by flagella ensuring its mobility. Such a fusiform form of the microorganism is rather difficult to determine during a laboratory examination, since it is found only in the body of an insect carrier of the disease or in an artificial environment.
The main varieties of parasites
Doctors distinguish about 30 main types of protozoan parasites of this type, but the following types of Leishmania are among the most common and negatively affecting the human body:
- Leishmania tropica (divided into two subspecies) - Leishmania tropica major (a form distributed in the countries of the New World) and Leishmania tropica minor (a form that occurs most often in the territory of the Old World);
- Leishmania class Leishmania donovani (second name - Leishmania infantum);
- Leishmania mexicana;
- Leishmania braziliensis and other varieties of parasites that spread across different climatic regions of the planet.
Leishmania donovania is the causative agent of visceral leishmaniasis, and the form of the tropic (minor or major) leads to the appearance of skin disease. The morphology of each individual species is similar.
Parasite life
The life cycle of Leishmania can be very different. For example, the obligate form of microorganisms, which cannot exist separately from the organism of its owner, is able to multiply freely only in the cells of the carrier, parasitizing. The life cycle of Leishmania presupposes successively several carriers - a mosquito, as well as mammals (this group also includes the person himself).
The parasite first enters the digestive tract of a female mosquito after it has bitten a sick mammal. Together with blood, microorganisms remain inside the body of the insect and begin to multiply actively in the upper intestine. After a week of active development and growth, microorganisms block the digestive tract of the mosquito. As a result of this, the insect has to burp the contents of the tract during the bite. Together with the intestinal contents, Leishmania penetrate the human body and begin to multiply and develop already in a new carrier. This is exactly how the vicious circle of penetration of parasites into the organism of carriers goes.
Invasive stage and parasite viability
At the time of a person’s bite by a diseased insect, promastigotes penetrate into the blood of a future host - an invasive progression stage in which parasites are initially absorbed by human granulocytic leukocytes. Within neutrophils, invasions cease to develop for some time. After the breakdown of neutrophils, the human immune system is activated, in which Leishmania is absorbed by macrophages. Inside the macrophage, as well as individual reticulo-endothelial cells, the main life cycle of Leishmania takes place, in which the morphology of microorganisms changes to the shape of the amastigote. The process of rapid multiplication of the infection begins.
The overall viability of parasites inside macrophages is provided by a parasitophore vacuole, in which microorganisms feed on its contents and preserve the life cycle for the next day. At the end of the life cycle of Leishmania, an infiltrate is formed on the lesion site, which includes macrophages, plasma, and lymphoid cells.
Diseases and signs of their development
The presence of parasites leads to the appearance in humans of a disease such as leishmaniasis. The disease is further divided into three main types:
- cutaneous - tropical leishmania acts as an infection;
- mucocutaneous - the causative agent is Leishmania Brazilyleneis;
- visceral - occurs when the microorganism donovani spreads in the body of a mammal.
The skin form of Leishmania actively develops and multiplies in open areas of the human body. The main sign of such a disease is the formation on the human body after 3-5 weeks after infection of irregularly shaped papules, which after change to ulcerated areas with uneven borders and sharp edges.
The duration of the development of the disease in the body
The disease, depending on the state of immunity of the carrier, can last a different period of time - from several weeks to several months. If the immune system suffers greatly and is not able to actively resist microorganisms, then relapses can occur. After eliminating the papule, the skin area is restored, but an apparently unpleasant scar remains on it. Mucocutaneous leishmaniasis resulting from Leishmania braziliensis not only spreads to open areas of the body, but also affects the mucous membranes (most often the upper respiratory tract).
The visceral form of Leishmania affects, as a rule, the internal organs of a person. The most affected are the liver, spleen and large intestine. The disease leads to complications, which include an increase in the size of the organ and compaction of its tissues.
Symptoms of lesion
Diagnosis of Leishmania is carried out based on the clinical picture:
- the incubation period, which can last only a few weeks or 3-10 months;
- the patient’s condition is significantly complicated by prolonged fever, an increase and decrease in body temperature, a feeling of heat and chills of the limbs;
- problems with intestinal absorption function, dyspeptic disorders, anemia (a condition characteristic of visceral leishmania);
- if Leishmania is of skin type, then a characteristic rash appears on the human body, after some time it turns into noticeable scars.
Often with poor immune defense, the disease is complicated and goes away against a purulent infection of the skin and mucous membranes, severe bleeding, as well as sepsis. Severe forms of Leishmania disease in some cases lead to the death of the patient. However, a fatal outcome occurs very rarely and only if the patient has been ignoring treatment for a long time.
How is the treatment carried out?
In the treatment of a disease, various combinations of drugs are used to combat parasites - antiseptic agents and antibiotics, which are important for stopping the spread of pathogens at the site of infection. Also, special medicines with antimony in the composition and immunomodulating drugs are used.
Who is affected?
A direct relationship between gender, age or social status of a person with lesions of leishmaniasis has not been established. But the poor are most affected by this disease, who cannot afford to eat healthy foods with a lot of nutrients and minerals. The body of such people does not have sufficient immunity and vitality to carry out a normal fight against a developing infection.
If the human immune system is strong and resistant to disease, then the cure usually occurs faster. With good body protection and proper treatment, the prognosis of doctors is favorable.
Leishmania Prevention
To prevent the onset of the epidemic, it is important to carry out comprehensive prevention, which will consist in actively observing basic sanitary and epidemiological standards and conducting quarantine studies on the deratization and disinfection of people's places of residence.
Preventive measures include restrictions on communication with infected people, the use of special repellents and other means to deter harmful insects that transmit the disease, as well as the creation of mechanical barriers from mosquitoes that penetrate a person’s home through open windows.
Caution
According to statistics, more than one billion people are carriers of unpleasant parasites. Some people do not even know that they are infected with dangerous microorganisms. To detect the presence of parasites in the body with the non-dermatological form of Leishmania can only be one characteristic feature - the presence of an unpleasant odor from the oral cavity. To do this, ask your loved ones if it smells from your mouth (before you clean your mouth). If so, then the likelihood of the presence of parasites in the body reaches 99 percent.
- Defeat with leishmaniasis provokes a person's severe mental disorders, fatigue, frequent mood swings. In the future, more dangerous diseases begin.
- In men, parasites provoke the development of the following conditions: prostatitis, adenoma, cystitis, sand and stones in the kidneys and bladder, as well as impotence at an early age.
- In women: ovarian inflammation and pain. Female carriers suffer from fibroma, fibroids, fibrocystic mastopathy, inflammation in the adrenal glands and kidneys, as well as diseases of the cardiovascular system.
If you have such a disease, you should not immediately rush to the pharmacy and buy expensive drugs that, according to pharmacists, will help eliminate the danger. Many medicines do not bring any effect, and at the same time cause serious harm to the human body. At the first sign of damage, it is important to immediately consult a doctor and begin treatment.
What is the danger?
Mosquitoes, as well as mosquitoes, cause Leishmania. After a female mosquito, infected with parasites, bit a person, the incubation period in the carrier’s body continues for a month. With cutaneous leishmania, the patient begins an active process of destruction of the skin. After healing, unpleasant and highly noticeable scars remain on the skin. Such an infection is dangerous in that it can lead to the onset of tuberculous cutaneous leishmaniasis, which will provoke a fatal outcome.
The spread of infection on the skin and mucous membranes can lead to severe deformation of the affected tissues and cartilage, which will lead to the formation of polyps. Most often, the disease spreads to the respiratory system: trachea, nasopharynx, larynx.
The most dangerous is visceral leishmaniasis in humans. The disease can persist in a latent form for a long time, so the patient will not even know about the presence of a lesion. An infection of this type affects the internal organs of a person to a greater extent, namely the spleen and liver.
A large accumulation of insect vectors is observed in the urban area near garbage dumps and in damp basements of houses. Under natural conditions, mosquitoes live nearby with burrows, caves, bird nests and wildlife dens.