The simplest human parasites - types and diseases that cause them

The simplest organisms that live in the water, soil and air of the earth number up to 15, 000 species. Some of them are the oldest inhabitants of our planet. In the millions of years that have passed since the first living organism appeared, most protozoa have changed little. But they learned to adapt well to new living conditions and to find ways to survive. One of the most obvious modes of existence of these organisms is parasitism, also in the human body.

parasitism

This is a kind of complex relationship between two living things when a parasite uses another organism as a habitat or a source of food.

The organism in which the parasite lives is called the host. It can be permanent if the parasite goes through the entire development cycle in it, and intermediate if the pathogenic organism only spends a certain phase of the life cycle in it.

Parasitism among protozoa is a type of interaction that not only involves living and parasitizing at the expense of others, but also poses a threat to the life of the host, since many types of parasites have serious forms of disease in humans, farm animals and agricultural crops.

The simplest human parasites have chosen almost all the organs and systems of the human body, they develop quite actively and sometimes live in it for years. This symbiosis leads to the chronicity of the disease and a decrease in the effectiveness of the treatment process.

Routes of entry into the body:

• through the hands and the mouth;
• through the skin;
• Contact;
• Transmission from mother to fetus;
• with insect bites, animals;

A comprehensive science that studies the phenomenon of parasitism, the biology of parasites and the range of their distribution, diagnostics, methods of treatment and prevention of parasitic diseases.

The simplest pathogenic parasites that cause various forms of disease can be found almost everywhere. These are fresh and salt water, earth, various household items and household items, public places. Protozoal infections are known as protozoal or protozoal infections.

What are the simplest human parasites?

The human body, like the body of a more or less large animal, is a very attractive object for parasitic life patterns. In addition to protozoa, multicellular parasites (helminths) can also colonize the human body.

Depending on the habitat, the simplest species can be endogenous (living in the human body) or exogenous (depending on the choice of the skin as the place of residence). Sometimes parasites move around the body during their development and choose the habitat that is most suitable for a particular stage of development.

Microscopic size and the presence of a primitive structure allow the simplest parasites to successfully survive and multiply in the most difficult conditions. All representatives of this type are distinguished by a structure consisting of a single cell filled with cytoplasm with intracellular fluid, in which all metabolic processes with the participation of organelles (structures that perform various functions for maintaining vital activity) take place.

The movement functions can be taken over by the flagella, cilia and pseudopodia provided for this purpose. The main process (food) is carried out in several ways:

• Swallowing through the cell mouth;
• flow around with pseudopods (pseudopods);
• Absorption through the membrane surface.

Adverse conditions can signal the formation of cysts that are resistant to the external environment of the membranes. They are necessary for the simplest of human parasites to travel from one host to another and can keep a captive in the parasite for up to several years.

A reproductive cyst is characterized by the formation of a thin temporary covering, which is necessary for a protozoon to divide for a short time.

Important!The simplest human parasites are the causative agents of protozoal infections: giardiasis, trichomoniasis, sleeping sickness, amoebic dysentery, malaria.

Types of protozoal parasites

In terms of reproduction and exercise, the nature of diet, there are 4 main classes of the simplest human parasites:

Scourges

For example Lamblia, Leishmania, Trichomonas, Trypanosomes. They have an elongated oval or pear-shaped body. They can have 1 to 8 flagella of thin cytoplasmic outgrowths made up of the finest fibrils. They move forward with a flagellum, as if screwing their way into the space in front of them. They feed themselves both by absorbing finished nutrients and by absorbing them through the membrane. In most cases, reproduction takes place by simply dividing into two daughter cells. Flagellates can live in colonies of up to 10, 000 individuals.

Sporozoa

For example malaria plasmodia, toxoplasma from Gondia. A very complex development path is characteristic of representatives of this species of protozoa: from the carrier to the human blood, then to the liver, where the parasite multiplies and attacks the red blood cells. Reproductive toxins cause disease in the human host. For the next development cycle, pathogens must re-enter the host's body, where the maturation of male and female cells and the formation of spores take place. After ripening, the spores are destroyed and the parasite re-enters the host's body. The cycle repeats itself.

Ciliates

For example balantidia. For ciliates, the movement with the help of cilia is characteristic. There are two nuclei in the body cell: the large nucleus controls all vital processes, the small one is assigned the main role on the sexual side of the existence of protozoa. The reproduction takes place by halving the cell, with most representatives of the species this happens daily, sometimes several times a day. Food is driven into a special cavity (cell mouth) by the movement of the cilia, processed inside the cell by the digestive vacuole and undigested residues are transported to the outside.

Sarcode

The amoeba, for example, is dysentery. It does not have a constant shape, forms many pseudopodia, with the help of which it moves and grabs food. It is multiplied by simple division. It can come in different forms: tissue, luminal, precystic. The tissue form only lives in the intestine of a sick person. The rest of the forms are also in the host's body.

Important!The primitive structure, the formation of cysts, the easiest mode of reproduction, the microscopic size, all these factors allow the simplest parasites to invade the most protected tissues of the human body and without adverse effects to the source of a. to become a series of serious and sometimes difficult to diagnose pathological conditions.

What diseases are caused by protozoal parasites?

The parasitic lifestyle of the simplest microorganisms, in addition to the factors listed above, is also facilitated by their ability to breathe anaerobically, although many can use dissolved oxygen.

Diseases caused by protozoal parasites include:

malaria

The main symptoms are fever attacks, joint pain, vomiting, anemia, convulsions. The spleen can become enlarged. Malaria is characterized by a recurring course of the disease with periods of rest and exacerbations. Depending on the type of pathogen, a distinction is made between forms: three-day, four-day and tropical. The disease is common in Africa and South Asia. For many centuries, as it is today, the main remedy has been quinine, a medicine extracted from the bark of the cinchona tree. Despite the production of synthetic analogs, deaths from infections occur in areas without access to modern medical care.

Amebiasis (dysentery amebiasis)

It is caused by the simplest parasite amoeba of the dysentery class, the sarcodes. The infection can occur intestinally and extraintestinally (development in the liver). The first symptoms appear 7-10 days after infection: abdominal pain, weakness, slight fever (up to + 37. 5 ° C). About 10% can develop severe diarrhea with traces of blood and mucus. Every third person infected develops a fever. It is characterized by an enlarged liver and, in some cases, a liver abscess. If treatment is not started on time, persistent diarrhea leads to dehydration, weakness, and exhaustion of the patient's body. Outbreaks of the disease are typical of countries with hot climates.

Giardiasis

The disease is caused by the simplest class of flagellate lamblia. These parasites have 4 pairs of flagella and a suction disc that they use to lodge inside the small intestine. Symptoms of infection include: pain and bloating in the upper abdomen, growling and nausea, disruption of normal bowel function, skin lesions (atopic dermatitis), gallbladder dysfunction, general weakness and loss of strength, poor appetite and sleep. Giardiasis is widespread in regions with hot climates in Asia, Africa, and Latin America.

Leishmaniasis

The disease is caused by a flagellate class of leishmania parasite. The main symptoms of cutaneous and mucocutaneous leishmaniasis are lesions of the skin in the form of ulcers. With a mucocutaneous form, edema and deformations can occur. In rare cases, if the respiratory tract is affected, it can be fatal. The visceral form is characterized by enlarged liver and spleen, fever, and anemia. The disease is common in 88 countries, mainly with tropical and subtropical climates.

Trichomoniasis

The disease is caused by the flagellate parasite Trichomonas. The genitourinary system is affected. The main symptoms in women are itching and burning, hyperemia of the external genital organs, discharge with an unpleasant smell, sometimes there may be discomfort during intercourse and urination. In men, the disease is asymptomatic in most cases, sometimes painful urination and discharge may appear, symptoms of prostatitis may appear.

Balantidiasis

The pathogen is a parasite from the class of the ciliates Balantidia. A characteristic symptom is abdominal pain, diarrhea and the lining of the tongue. In acute cases of the disease, a rise in temperature, signs of general intoxication are possible. The infection can also be chronic, with intermittent periods of remission and exacerbation. In complicated cases, intestinal perforation and peritonitis are possible.

Toxoplasmosis

The disease is caused by the toxoplasma parasite of Gondia, a sporozoal parasite. The characteristic symptoms of the disease are damage to the eyes, nervous system, heart muscles, enlargement of the lymph nodes, liver and spleen. It is mainly chronic. Often times, primary infection is very easy under the guise of a common ARVI. After that, immunity appears forever, and further infection is impossible. The greatest danger to the fetus is during pregnancy: if the child survives, it will cause severe damage to the nervous system and eyes.

Sleeping sickness

The disease is caused by the simplest parasite of the flagellate class, the Gambian or Rhodesian trypanosome. The characteristic signs in the first stage are fever, headache and joint pain. After 7-20 days, the second phase of the disease begins: disorders in the perception of the environment begin, disorders in movement coordination, numbness and sleep disorders. Outbreaks of the disease are localized in certain regions of tropical Africa, the habitat of the main vector of tsetse fly infection;

Chagas disease

The pathogen is a parasite from the class of the flagellates Trypanosoma cruzi. The main symptoms are fever, swollen lymph nodes, headache, and swelling at the bite site. In the initial stage, signs of the disease may be absent, and after 8-12 weeks, secondary symptoms may develop in 30-40%: an increase in the ventricles of the heart, an enlargement of the esophagus, an enlargement of the large intestine. The second stage of the disease can persist for 10-30 years after infection. The infection was most widespread in Latin America.

Important!Most of the simplest parasites get into the human body if the basic rules of hygiene and personal hygiene are not observed.

Routes of infection

The penetration of microorganisms into the human body can occur through penetration through the skin or natural openings. For most of the protozoal parasites found in the environment, methods of human infection are limited to the four most common:

1. Contact and household. This route of infection is available to the simplest organisms in violation of hygiene and hygiene regulations. After all, most microorganisms, when passing from the body of one host to the body of another, can form cysts and remain in this state until they get into a favorable environment, that is, inside a person. An infection can occur at any time: when shaking hands, when using other household items (towels, bed linen, dishes), when washing hands with dirty water (in a pond);
2. Fecal-oral (giardiasis). In this case, infection occurs when the parasite leaves the intestines with feces or vomit. If the hygiene rules are not observed, the parasite will end up in the water, food or hands of the new host and get into the body. Badly washed vegetables and herbs can also become a source of infection, and children can get dirty hands after playing in the sandpit or with pets;
3. Through contaminated food (toxoplasmosis). The meat of most animals, especially wild animals, can contain cysts of protozoal parasites that enter the human body if insufficiently heat-treated. Infection is also possible from dairy products that have failed hygiene control and raw fish without adequate heat treatment;
4. Communicable (malaria, sleeping sickness). The infection takes place through the transmission of the pathogen through the saliva of the carrier with the bite. The disease is transmitted directly to a susceptible organism by infected insects.

In addition to the main methods of infection, infection can occur in several more ways, which are much less common:

• Transplacental with the penetration of protozoal parasites from the infected mother through the placenta to the fetus;
• Hemocontact, when blood infected with parasites enters the patient's body (during medical procedures, narcotic injections, during sexual intercourse);
• Sexual infection occurs only through sexual contact.

prevention

Preventing an infection with protozoal parasites primarily includes compliance with all hygiene and hygiene regulations. The exclusion of the possibility of parasite infection can be achieved by judiciously following a number of recommendations:

• Heat treatment of meat, dairy and fish products is sufficient (in accordance with the thermal regime according to the technology). Particular attention is paid to products that have not passed the hygiene control;
• Thorough washing of fruits, vegetables, berries and herbs, preferably with boiling water. If heat treatment is impossible, especially for feeding children, it is better to remove the skin;
• Regular medical examinations, especially if an infection with protozoal parasites is suspected;
• Sticking to a sexual partner and refusing to use drugs;
• Specific measures can be taken to prevent infection from insect bites: the use of medication, the destruction of mosquitoes, mosquito nets and repellants, the elimination of transgenic (malaria-resistant) mosquitoes, the production of a vaccine.

Important!Of great importance in preventing infections, including the simplest of human parasites, is the body's resilience. If a cyst gets into an unfavorable condition, if it lacks food or if immune cells constantly attack a foreign body, the parasite either dies or leaves the host's body.

There are a number of foods that are natural immune stimulants (garlic, ginger, broccoli, carrots, green tea) that, when taken in a balanced way, can provide invaluable help to the body in strengthening immunity.

In addition, some products have a negative effect on the growth and reproduction of protozoa, especially those that have settled in the digestive tract: rice and barley porridge, dried fruits, baked apples, vegetable oil, steamed vegetables. When treating parasites, it is necessary to limit or completely exclude products that provoke fermentation processes: baked goods and sugar.

Currently, the pharmaceutical industry offers many expensive anti-parasitic drugs. However, their effective use can only be achieved in combination with preventive measures and compliance with a certain diet, the composition of which can be consulted by a qualified specialist.

Do not forget about the tried and tested folk remedies and many generations. With a combination of all methods and under medical supervision, parasites hardly stand a chance.

diploma

At the beginning of the 21st century, it should be noted that mankind has achieved a lot in the development of parasitology. News of a new discovery of a particular drug is always welcomed by people in need of help and treatment today.

The simplest human parasites are still a serious problem in many countries where the level of development of medicine and society as a whole leaves much to be desired. There are many other places on our planet where diseases such as malaria, sleeping sickness, leishmaniasis and many others are widespread. And people wait and hope that everyone has a chance to live without disease.

Parasitic diseases in our time are relevant, they require social interaction in all areas of human life, aimed at improving medical care for the population, observing the rules and norms of personal and public hygiene, preventive measures and sanitary and educational work, hygienethe natural herd of pathogenic organisms.

Various scientific studies in the field of parasitology are currently being carried out in many countries around the world:

• Development of scientific principles and methods for monitoring infectious and parasitic infections;
• Study of the biological properties and variability of the causative agents of the main diseases caused by protozoal parasites;
• Quality control and environmental safety of meat and fish products;
• Carrying out basic research to research the development of pathogens causing parasitic diseases, their genetic variability, ecology.