The simplest human parasites - the species and the diseases they cause

The simplest organisms living in water bodies, the earth and the 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 appearance of the first living organism, most protozoa have hardly changed. But they learned to adapt well to new living conditions and find ways to survive. One of the most obvious ways of existence for these organisms has become parasitism, involved in the human body.

Parasitism

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

The organism in which the parasite lives is called the host. It can be permanent when the parasite goes through the whole cycle of its development in it and intermediate, when the pathogenic organism goes through only a certain stage of the life cycle.

Parasitism between protozoa is a type of interaction that involves not only living and parasitizing at the expense of another, but also poses a risk to the life of the host, as many types of parasites cause severe forms of the disease in humans, livestock and agricultural crops.

The simplest human parasites have selected 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 chronicity of the disease and a decrease in the effectiveness of the treatment process.

Ways of entering the body:

• through the hands and 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 their area of distribution, diagnosis, treatment methods and prevention of parasitic diseases.

The simplest pathogenic parasites that cause various forms of disease are found almost everywhere. These are fresh and salt water, soil, various household items and household items, public places. Protozoal infections are called protozoan or protozoal infections.

What are the simplest human parasites

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

Depending on the habitat, the simplest species can be endogenous (living inside the human body) or exogenous (after choosing the skin as their habitat). Sometimes, as they develop, the parasites move through the body, choosing the most suitable habitat for a particular stage of development.

The microscopic size and presence of a primitive structure allow the simplest parasites to survive and reproduce successfully in the most difficult conditions. All representatives of this species are characterized by a structure consisting of a single cell filled with cytoplasm with intercellular fluid, in which all metabolic processes occur with the participation of organelles (structures that perform various functions to maintain vital activity)

Movement functions can be performed by flagella, cilia and pseudopodia intended for this. The main process (food) is performed in several ways:

• swallowing from the mouth of the cell;
• flow around with pseudopods (pseudopods);
• absorption from the membrane surface.

Unfavorable conditions can become a signal for the formation of cysts that are resistant to the external environment of the membranes. They are necessary for the simplest human parasites to move from one host to another and can hold an inmate inside the parasite for up to several years.

A reproductive cyst is characterized by the formation of a temporary thin shell, which is necessary for a protozoan for a short period of separation.

Important!The simplest human parasites are the causative agents of protozoan infections: giardiasis, trichomoniasis, sleep disorders, amoebic dysentery, malaria.

Types of protozoan parasites

From the way they reproduce and move, to the nature of nutrition, there are 4 main classes of the simplest human parasites:

With flags

For example, lamblia, leishmania, trichomonas, trypanosomes. They have an elongated oval or pear-shaped body. They may have from 1 to 8 flagella with thin cytoplasmic outlets, composed of the finest fibrils. They move forward with a flagellum, as if screwed into the space in front of them. They feed both by absorbing ready-made nutrients and by absorbing them through the membrane. Reproduction occurs in most cases by simple division into two daughter cells. Flagellates can live in colonies of up to 10, 000 individuals.

Sporozoans

For example, malaria plasmodia, Toxoplasma and Gondia. For representatives of this protozoan species, a very complex path of development is characteristic: from the transporter to human blood, then to the liver, where the parasite multiplies and affects red blood cells. Reproductive toxins cause disease in the human host. For the next developmental cycle, pathogens must re-enter the host body, where the maturation of male and female cells and the formation of spores occur. Upon maturation, the spores are destroyed and the parasite re-enters the host body. The cycle repeats.

Ciliates

For example, balantidia. For ciliates, movement with the help of eyelashes is characteristic. There are two nuclei in the cell of the body: the large nucleus controls all the vital processes, for the small one the main role is assigned to the sexual side of the protozoan existence. Reproduction occurs by dividing the cell in half, for most species representatives this happens every day, for some several times a day. Food is pushed into a special cavity (cell mouth) by the movement of the eyelashes, inside the cell is processed by the solvent vacuole, and the dissolved waste is not removed.

Sarkod

For example, the amoeba is dysentery. It does not have a constant shape, it forms many pseudopods, with the help of which it moves and catches food. Multiplies by simple division. It can exist in several forms: tissue, luminal, precast. The tissue form lives only in the intestines of a sick person. The rest of the shapes can also be found on the host body.

Important!The primitive structure, the formation of cysts, the simplest way of reproduction, the microscopic size, all these factors allow the simplest parasites to penetrate into the most protected tissues of the human body and, in the absence of negative effects, become the source ofa number of serious and sometimes difficult pathological conditions to diagnose.

What diseases are caused by protozoan parasites

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

Diseases caused by protozoan parasites include:

Malaria

The main symptoms are fever attacks, joint pain, vomiting, anemia, convulsions. There may be an enlargement of the spleen. Malaria is characterized by a recurrent course of the disease, with periods of rest and worsening. Depending on the type of pathogen, the forms are distinguished: three-day, four-day and tropical. The disease is common in Africa and South Asia. For many centuries, as today, the main medicine for treatment has been quinine, a medicine made from the bark of the cinchona tree. Despite the creation of synthetic analogues, deaths from infection occur in areas without access to modern medical care.

Amoebiasis (amebiasis dysentery)

It is caused by the simplest parasitic amoeba of the class of sarcoid dysentery. The infection can be intestinal and extra-intestinal (development in the liver). 7-10 days after infection, the first symptoms appear: abdominal pain, weakness, low-grade fever (up to + 37. 5 ° C). About 10% may develop severe diarrhea, with traces of blood and mucus. Every third infected person develops fever. It is characterized by an enlarged liver and, in some cases, a liver abscess. If treatment is not started on time, then prolonged diarrhea causes dehydration, weakness and exhaustion of the patient's body. Disease spreads are typical of hot climates.

Giardiasis

The disease is caused by the simplest class of lamblia flagellate. These parasites have 4 pairs of flagella and a suction disc, with which they attach to the inside of the small intestine. When infected, symptoms appear: pain and swelling in the upper abdomen, rumble and nausea, disruption of normal bowel function, skin lesions (atopic dermatitis), abnormal gallbladder function, general weakness and loss of strength, poor appetite and sleep. Giardiasis is prevalent in regions with hot climates in Asia, Africa and Latin America.

Leishmaniasis

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

Trichomoniasis

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

Balantidiasis

The causative agent is a parasite of the balantidia ciliates class. A characteristic symptom is abdominal pain, diarrhea, and lining of the tongue. In acute cases of the disease, an increase in temperature, signs of general intoxication are possible. The infection can also be chronic, with intermittent periods of remission and worsening. In complicated cases, intestinal perforation and peritonitis are possible.

Toxoplasmosis

The disease is caused by the parasite Toxoplasma gondia, a sporozoan parasite. Characteristic symptoms of the disease are damage to the eyes, nervous system, heart muscle, enlarged lymph nodes, liver and spleen. Continues mainly in a chronic form. Often, the primary infection is very mild, under the guise of a common ARVI. After that, immunity appears forever, and further infection is impossible. The greatest risk is to the fetus during pregnancy: if the baby survives, then with severe damage to the nervous system and eyes.

Sleep sickness

The disease is caused by the simplest flagellate class parasite, the Gambian or Rhodesian trypanosome. The characteristic signs in the first stage are fever, headache and joint pain. After 7-20 days, the second stage of the disease begins: disturbances in the perception of the surrounding world begin, interruptions in coordination of movements, numbness and sleep disturbance. Outbreaks appear to be exacerbated during certain parts of tropical Africa.

Chagas disease

The causative agent is a parasite of the flagellate grade of trypanosoma cruzi. The main symptoms are fever, swollen lymph nodes, headache and swelling at the site of the bite. In the initial stage, the signs of the disease may be absent, and after 8-12 weeks, secondary symptoms may begin to appear in 30-40%: an increase in the ventricles of the heart, an enlargement of the esophagus, an enlargement of the colon. The second stage of the disease can last 10-30 years after infection. The infection was most prevalent in Latin America.

Important!Most of the simplest parasites enter the human body if the basic rules of hygiene and personal hygiene are not followed.

Routes of infection

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

1. Contact and family. This route of infection becomes available to the simplest organisms in violation of the rules of hygiene and personal hygiene. After all, most microorganisms, when they pass from one host's body to another's body, can form cysts and stay in that state until they enter a favorable environment, in other words, within a person. Infection can occur at any time: when shaking hands, use other people's household items (towels, linen, dishes), wash hands with contaminated water (in a pond);
2. Fecal-oral (giardiasis). In this case, the infection occurs when the parasite leaves the intestines with feces or vomit. If hygiene rules are not followed, the parasite enters the water, food or hands of the new host and enters the body. Poorly washed vegetables and herbs can also become a source of infection, and for children, dirty hands after playing in the sandbox or with pets;
3. Through contaminated foods (toxoplasmosis). The meat of most animals, especially wild ones, can contain protozoan parasite cysts, which, with insufficient heat treatment, enter the human body. Infection is also possible through dairy products that have not passed sanitary control, and raw fish without adequate heat treatment;
4. Transmissible (malaria, sleep sickness). Infection occurs by transmission of the pathogen through the carrier saliva when bitten. The disease is transmitted by infected insects directly to a susceptible organism.

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

• Transplacental with penetration of protozoan parasites from infected mother through placenta to fetus;
• Hemocontact when parasite-infected blood enters the patient's body (during medical procedures, narcotic injections, during sexual intercourse);
• Sexually transmitted infections occur only through sexual contact.

prevention

Prevention of infection with protozoan parasites involves, first of all, observance of all rules of hygiene and hygiene. The exclusion of the possibility of parasitic infection can be achieved by reasonably following a number of recommendations:

• Thermal treatment of meat, dairy and fish products is sufficient (in accordance with the thermal regime according to the technology). Special attention is paid to products that have not passed the sanitary control;
• Thorough washing of fruits, vegetables, berries and herbs, preferably with boiling water. If heat treatment is impossible, especially for baby food, it is better to remove the skin;
• Regular medical examinations, especially if protozoan parasite infection is suspected;
• Respecting a sexual partner and refusing to use drugs;
• Specific measures can be taken to prevent infection from insect bites: use of medicines, destruction of mosquitoes, mosquito nets and medicines, elimination of transgenic (malaria-resistant) mosquitoes, creation of a vaccine.

Important!Of great importance in preventing any infection, including the simplest human parasites, is the level of resistance of the body. After all, if a cyst enters unfavorable conditions, where it lacks food, or immune cells constantly attack a foreign object, then the parasite will either die or leave the host body.

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

Moreover, some products have a negative effect on the growth and reproduction of protozoa, especially those that are placed in the digestive tract: rice barley porridge, dried fruits, ripe apples, vegetable oil, boiled 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 antiparasitic drugs. However, their effective use can be achieved only in combination with preventive measures and adherence to a certain diet, the composition of which can be consulted by a qualified specialist.

Do not forget about folk remedies, time-tested and many generations. In the case of a combination of all methods and techniques under the supervision of a physician, parasites will have very few options.

cONcluSiON

At the beginning of the 21st century, it can be seen that humanity has achieved a lot in the development of parasitology. The message of a new discovery of a particular medicine is always gladly accepted by the people who need 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 like malaria, sleep disorders, leishmaniasis and many others are rampant. And people expect and hope that everyone has a chance to live without disease.

Parasitic diseases in our time are important, they require social interaction in all spheres of human life, aimed at improving medical care for the population, respecting the rules and norms of personal and public hygiene, carrying out preventive measures and sanitary and educational work. , sewers of natural foci of pathogenic organisms.

At present, in many countries of the world, various scientific studies are being conducted in the field of parasitology:

• development of scientific bases and methods for monitoring infectious and parasitic infections;
• study of the biological characteristics and variability of the causative agents of major diseases caused by protozoan parasites;
• quality control and environmental safety of meat and fish products;
• conducting basic research to study the development of pathogens of parasitic diseases, their genetic variability, ecology.