The simplest organisms that live in water bodies, soil and air on Earth number up to 15, 000 species. Some of them are the oldest inhabitants of our planet. In the millions of years since the first living organism appeared, most of the simplest have not changed. But they have learned to adapt well to new living conditions and find ways to survive. One of the most obvious ways for these organisms to exist has become parasitism, including in the human body.
Parasitism
It is a kind of complex relationship between two beings when one parasite uses another organism as a habitat or food resource.
The organism in which the parasite lives is called the host. It can be permanent when the parasite passes through the entire cycle of its development in it, and intermediate when the pathogenic organism spends in it only a certain stage of the life cycle.
Parasitism among protozoa is a type of interaction that involves not only living and parasitizing at the expense of another, but also threatening the life of the host, as many species of parasites cause severe forms of disease in humans, livestock and crops.
The simplest human parasites have chosen almost all 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 reduction of the effectiveness of the healing process.
Ways to enter the body:
- through the hands and mouth;
- through the skin;
- contact;
- mother-to-child transmission;
- with insect bites, animals;
A comprehensive science that studies the phenomenon of parasitism, the biology of parasites and the field of their distribution, diagnosis, methods of treatment 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 and household items, public places. Protozoan infections are called protozoal or protozoan infections.
Which 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 inhabit the human body.
Depending on the habitat, the simplest species can be endogenous (living in the human body) or exogenous (having chosen the skin for residence). Sometimes, as they develop, parasites move through the body, choosing the habitat most suitable for a particular stage of development.
The microscopic size and the presence of a primitive structure allow the simplest parasites to survive successfully and reproduce in the most difficult conditions. All members of this species are characterized by a structure consisting of a cell filled with cytoplasm with intracellular fluid, in which all metabolic processes take place with the participation of organelles (structures that perform various functions to maintain vital activity)
The functions of movement can be performed by designated flags, cilia and pseudopodia. The main process (food) is done in several ways:
- ingestion by the mouth of the cell;
- go around with pseudopods (pseudopods);
- absorption from the membrane surface.
Adverse conditions can become a signal for the formation of cysts resistant to the external environment of the membranes. They are necessary for the passage of the simplest human parasites from one host to another and can keep a prisoner inside the parasite for up to several years.
The reproductive cyst is characterized by the formation of a thin temporary shell, which is needed for protozoa for a short period of division.
Important!The simplest human parasites are the causes of protozoal infections: giardiasis, trichomoniasis, sleeping sickness, amoebic dysentery, malaria.
Types of protozoan parasites
In the way of reproduction and movement, the nature of nutrition has 4 main classes of the simplest human parasites:
Flagellate
For example, lamblia, leishmaniasis, Trichomonas, trypanosomes. They have an elongated oval or pear-shaped body. They can have from 1 to 8 flagella with thin cytoplasmic growths consisting 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 simply dividing two daughter cells. Flagella can live in colonies of up to 10, 000 individuals.
Sporozoans
For example, Plasmodium falciparum, Gondia toxoplasma. Representatives of this type of protozoa are characterized by a very complex path of development: from the carrier in human blood, then in the liver, where the parasite multiplies and affects red blood cells. Reproductive toxins cause disease in the human host. For the next cycle of development, the pathogens must re-enter the body of the host, where the maturation of male and female cells and the formation of spores occurs. After maturation, the spores are destroyed and the parasite re-enters the body of the host. The cycle repeats.
Infusoria
For example, balantidia. Eyelashes are characterized by movement with the help of eyelashes. There are two nuclei in the cell of the body: the large nucleus controls all vital processes, the small one is assigned the main role in the sexual side of the existence of protozoa. Reproduction is done by dividing the cell in half, for most members of the species this happens daily, for some several times a day. The food is driven into a special cavity (cell mouth) by the movement of the cilia, inside the cell it is processed by the digestive vacuole, and the undigested remains are removed outside.
Sarcode
For example, the amoeba is dysentery. It does not have a permanent shape, it forms many pseudo-legs, with the help of which it moves and grabs food. Multiplied by simple division. It can exist in several forms: tissue, luminal, precystic. The tissue form lives only in the intestines of a sick person. Other forms can also be found in the host's 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 the most protected tissues of the human body and in the absence of adverse effects to become a source of serious and sometimesdifficult to diagnose pathological conditions.
What diseases are caused by protozoan parasites
The parasitic lifestyle of the simplest microorganisms, in addition to the above factors, is facilitated by their ability to breathe anaerobically, although many of them can use dissolved oxygen.
Diseases caused by protozoan parasites include:
Malaria
The main symptoms are attacks of fever, 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 exacerbation. Depending on the type of pathogen, 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 is quinine, a medicine made from the bark of the chinchon tree. Despite the creation of synthetic analogues, deaths from infection occur in areas without access to modern medical care.
Amoebiasis (dysenteric amoebiasis)
It is caused by the simplest parasitic amoeba of the dysentery class sarcoids. The infection can be intestinal or extraintestinal (development in the liver). 7-10 days after infection, the first symptoms appear: abdominal pain, weakness, low temperature (up to + 37, 5 ° C). About 10% may develop severe diarrhea with traces of blood and mucus. Every third infected person develops a 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. Outbreaks appear to be exacerbated in countries with hot climates.
Giardiasis
The disease is caused by the simplest of the class of flagellar lamblia. These parasites have 4 pairs of flagella and a suction disk with which they attach to the inside of the small intestine. When infected, symptoms appear: pain and swelling in the upper abdomen, grunting and nausea, impaired bowel function, skin lesions (atopic dermatitis), abnormalities in the functioning of the gallbladder, general weakness and loss of strength, poor appetite andsleep. Giardiasis is widespread in hot climates in Asia, Africa and Latin America.
Leishmaniasis
The disease is caused by the parasite leishmaniasis of the flagella class. The main symptoms of cutaneous and mucocutaneous leishmaniasis are skin lesions in the form of ulcers. In the mucocutaneous form, swelling and deformity may occur. If the airways are affected, in rare cases this can be fatal. The visceral form is characterized by an 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 parasite Trichomonas from the class of flagella. The affected 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 excretion, symptoms of prostatitis may occur.
Balantidiase
The causative agent is a parasite of the class of cilia balantidia. Typical symptoms are abdominal pain, diarrhea and the lining of the tongue. In acute cases of the disease are possible fever, signs of general intoxication. The infection can also be chronic, with periodic periods of remission and exacerbation. In complex cases, intestinal perforation and peritonitis are possible.
Toxoplasmosis
The disease is caused by the parasite Toxoplasma of Gondia, a sporozoic parasite. Typical symptoms of the disease are damage to the eyes, nervous system, heart muscle, enlarged lymph nodes, liver and spleen. It occurs mainly in a chronic form. Often the primary infection is very easy, under the guise of common ARVI. Then the immunity appears forever and further infection is impossible. The greatest danger is to the fetus during pregnancy: if the child survives, then with severe damage to the nervous system and eyes.
Sleeping sickness
The disease is caused by the simplest parasite of the flagella class, the Gambian or Rhodesian trypanosome. The characteristic signs of the first stage are fever, headache and joint pain. After 7-20 days, the second phase of the disease begins: disturbances in the perception of the surrounding world, disturbances in the coordination of movements, numbness and sleep disturbance begin. Outbreaks of the disease are localized in certain regions of tropical Africa, the habitat of the main vector of infection with the tsetse fly;
Chagas disease
The causative agent is a parasite of the class of flagellate trypanosomes. 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 may begin to develop secondary symptoms in 30-40%: enlargement of the ventricles of the heart, dilation of the esophagus, enlargement of the colon. The second stage of the disease can last 10-30 years after infection. The infection is most common 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
The 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, methods of human infection are limited to the four most common:
- Contact and household. This route of infection becomes accessible to the simplest organisms in violation of the rules of hygiene and personal hygiene. After all, most microorganisms, when they pass from the body of one host to the body of another, can form cysts and remain in that state until they enter a favorable environment, in other words, inside a person. The infection can occur at any time: when shaking hands, using other people's household items (towel, linen, plates), washing hands with dirty water (in a pond);
- Fecal-oral (giardiasis). In this case, the infection occurs when the parasite leaves the intestines with feces or vomits. If the rules of hygiene 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 be a source of infection, and for children, dirty hands after playing in the sandbox or with pets;
- Through contaminated food (toxoplasmosis). The meat of most animals, especially wild animals, may contain cysts of protozoan parasites, which enter the human body when insufficiently treated. Infection is also possible through dairy products that have not passed sanitary control, and raw fish without sufficient heat treatment;
- Transmitted (malaria, sleeping sickness). The infection occurs by transmitting the pathogen through the saliva of the carrier when bitten. The disease is transmitted from infected insects directly to a sensitive 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 the infected mother through the placenta to the fetus;
- Chemocontact, when the blood infected with parasites enters the patient's body (during medical procedures, drug injections, during sexual intercourse);
- Sexually transmitted infections occur only through sexual contact.
Prevention
Prevention of infection with protozoan parasites includes, above all, compliance with all rules of sanitation and hygiene. The exclusion of the possibility of parasite infestation can be achieved by reasonably following a number of recommendations:
- The heat treatment of meat, dairy and fish products is sufficient (observing the thermal regime according to the technology). Particular attention is paid to products that have not passed sanitary control;
- Carefully wash fruits, vegetables, berries and herbs, preferably with boiling water. If heat treatment is not possible, especially for feeding children, it is better to remove the skin;
- Regular medical examinations, especially if there is a suspicion of infection with protozoan parasites;
- Attachment to a sexual partner and refusal to use drugs;
- Specific measures can be taken to prevent infection from insect bites: the use of drugs, the destruction of mosquitoes, gnats and repellents, the elimination of transgenic mosquitoes (resistant to malaria), the creation of a vaccine.
Important!Of great importance for the prevention of all infections, including the simplest human parasites, is the level of resistance of the organism. After all, if a cyst gets into unfavorable conditions where there is a lack of food or the immune cells constantly attack a foreign object, then the parasite will either die or leave the host's body.
There are a number of foods that are natural immunostimulants (garlic, ginger, broccoli, carrots, green tea), which, when consumed in a balanced way, can be of invaluable help to the body to boost immunity.
In addition, some products have a negative effect on the growth and reproduction of the simplest, especially those that have settled in the digestive tract: rice and barley porridge, dried fruits, baked apples, vegetable oil, stewed vegetables. In the treatment of parasites it is necessary to limit or completely exclude products that provoke fermentation processes: pasta and sugar.
Currently, the pharmaceutical industry offers very expensive antiparasitic drugs. However, their effective use can be achieved only in combination with preventive measures and adherence to a specific 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 methods under the supervision of a doctor, the parasites will have a very small chance.
Conclusion
At the beginning of the 21st century, it can be noted that humanity has achieved a lot in the development of parasitology. The announcement of a new discovery of a particular drug is always welcomed by 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 such as malaria, sleeping sickness, leishmaniasis and many others are widespread. And people are waiting and hoping that everyone has a chance to live without disease.
Parasitic diseases are relevant today, they require social interaction in all spheres of human life, aimed at improving medical care for the population, compliance with the rules and norms of personal and public hygiene, preventive measures and sanitary-educational work, seweragenatural foci 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 bases and methods for monitoring of infectious and parasitic infections;
- study of the biological characteristics and variability of the causes of the main 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.