The simplest organisms that live in the Earth's water, soil and air bodies number 15, 000 species. Some of them are the oldest inhabitants of our planet. Over the millions of years that have passed since the first living organism appeared, most protozoa have barely changed. But they learned to adapt well to new living conditions and find ways to survive. One of the most obvious forms of existence for these organisms became parasitism, including in the human body.
Parasitism
This is a kind of complex relationship between two creatures, 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 goes through the entire cycle of its development in it and intermediate, when the pathogenic organism only passes a certain stage of the life cycle in it.
Parasitism among protozoa is a type of interaction that involves not only living and parasitizing at someone else's expense, but also representing a danger to the host's life, since many types of parasites cause serious forms of disease in humans, domestic animals and agricultural crops.
The simplest human parasites have chosen almost every organ and system in the human body, they develop very 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.
Ways of entry into the body:
- by 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 the area of their 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. Protozoan infections are called protozoan or protozoan 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 inhabit the human body.
According to the habitat, the simplest species can be endogenous (they live inside the human body) or exogenous (having chosen the skin as a place of residence). Sometimes, as they develop, the parasites move around the body, choosing the most suitable habitat for a particular stage of development.
The microscopic size and the presence of a primitive structure allow the simplest parasites to survive and reproduce successfully under the most difficult conditions. All representatives of this species are characterized by a structure consisting of a single cell filled with cytoplasm with intracellular 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 pseudopods designed for this. The main process (food) is carried out in several ways:
- swallow through the cell's mouth;
- flow with pseudopods (pseudopods);
- absorption by the membrane surface.
Unfavorable conditions can become a signal for the formation of cysts resistant to the external environment of the membranes. They are needed for the simplest human parasites to move from one host to another and can keep a prisoner inside the parasite for several years.
A reproductive cyst is characterized by the formation of a thin temporary shell necessary for a protozoan for a short period of division.
Important!The simplest human parasites are the causative agents of protozoan infections: giardiasis, trichomoniasis, sleeping sickness, amoebic dysentery, malaria.
Types of protozoan parasites
By the way of reproduction and movement, the nature of nutrition, there are 4 main classes of the simplest human parasites:
flagellate
For example lamblia, leishmania, trichomonas, trypanosomes. They have an elongated oval or pear-shaped body. They may have 1 to 8 thin cytoplasmic bulge flagella, consisting of the finest fibrils. They advance with a scourge, as if tangled up in the space in front of them. They feed by absorbing ready-made nutrients and 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.
Sporozoa
For example, malaria plasmodia, Toxoplasma of Gondia. For representatives of this species of protozoa, a very complex developmental path is characteristic: from the carrier to human blood, then to the liver, where the parasite multiplies and reaches red blood cells. Reproductive toxins cause disease in the human host. For the next developmental cycle, pathogens must re-enter the host's body, where male and female cells mature and spores form. After maturation, the spores are destroyed and the parasite re-enters the host's body. The cycle repeats.
Affiliates
For example, balantidia. For ciliates, movement with the help of the lashes 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 in the sexual side of protozoan existence. Reproduction occurs by dividing the cell in half, for most representatives of the species this happens daily, sometimes several times a day. Food is carried to a special cavity (mouth of the cell) by the movement of the cilia, inside the cell it is processed by the digestive vacuole and undigested waste is removed outside.
sarcode
For example, amoeba is dysentery. It does not have a constant form, it forms many pseudopods, with the help of which it moves and grabs food. It multiplies by simple division. It can exist in various forms: tissue, luminal, prehistoric. The tissue form only lives in the intestines of a sick person. The other forms can also be found in the host's body.
Important!The primitive structure, the formation of cysts, the simplest form 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, become the source of a number of serious and sometimes difficult-to-diagnose pathological conditions.
What diseases are caused by protozoan parasites
The parasitic lifestyle of simpler 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 attacks of fever, joint pain, vomiting, anemia, seizures. There may be an enlarged spleen. Malaria is characterized by a recurrent course of the disease, with periods of rest and exacerbation. Depending on the type of pathogen, the forms are different: three days, four days and tropical. The disease is common in Africa and South Asia. For many centuries, as today, the main remedy for treatment was 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.
Amebiasis (dysentery amoebiasis)
It is caused by the simplest parasitic amoeba of the dysentery sarcoid class. The infection can be intestinal and extraintestinal (developing in the liver). 7 to 10 days after infection, the first symptoms appear: abdominal pain, weakness, low-grade fever (up to +37, 5°C). About 10% can 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, prolonged diarrhea causes dehydration, weakness and exhaustion of the patient's body. Disease outbreaks are typical of countries with hot climates.
Giardiasis
The disease is caused by the simplest of the flagellate lamblia class. These parasites have 4 pairs of flagella and a suction disk, with which they attach themselves to the interior of the small intestine. When infected, symptoms appear: pain and swelling in the upper abdomen, snoring and nausea, disturbance of the normal functioning of the intestines, skin lesions (atopic dermatitis), abnormalities in the functioning of the gallbladder, general weakness and loss of strength, weak appetite and sleep. Giardiasis is common in hot climate regions in Asia, Africa and Latin America.
leishmaniasis
The disease is caused by a Leishmania parasite of the flagellate class. The main symptoms of cutaneous and mucocutaneous leishmaniasis are cutaneous lesions in the form of ulcers. In the mucocutaneous form, edema and deformation may occur. If the respiratory tract is involved, in rare cases it 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 in tropical and subtropical climates.
Trichomoniasis
The disease is caused by the parasite Trichomonas of the flagellate class. The genitourinary system is affected. The main symptoms in women are itching and burning, hyperemia of the external genital organs, presence of discharge with an unpleasant odor, sometimes there may be discomfort during sexual intercourse and urination. In men, in most cases, the disease is asymptomatic, sometimes painful urination and drying, symptoms of prostatitis may appear.
balantidiasis
The causative agent is a parasite of the balantidia class of ciliates. A characteristic symptom is abdominal pain, diarrhea and tongue lining. In acute cases of the disease, temperature rise, 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 can occur.
toxoplasmosis
The disease is caused by the Toxoplasma de Gondia parasite, a sporozoan parasite. The characteristic symptoms of the disease are damage to the eyes, nervous system, heart muscles, enlarged lymph nodes, liver and spleen. It mostly occurs chronically. Often, the primary infection is very easy, disguised as a common ARVI. After that, immunity appears forever and it is impossible to continue the infection. The greatest danger is for the fetus during pregnancy: if the child survives, it will suffer serious 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: disturbances in the perception of the surrounding world, disturbances in the coordination of movements, numbness and sleep disturbances begin. The disease outbreaks are located in certain regions of tropical Africa, habitat of the main vector of the tsetse fly infection;
Chagas disease
The causative agent is a parasite of the trypanosoma cruzi flagellate class. The primary symptoms are fever, swollen lymph nodes, headache and swelling at the bite site. In the early stage, signs of the disease may be absent, and after 8-12 weeks, secondary symptoms may start to develop in 30-40%: an enlargement of the heart ventricles, an expansion of the esophagus, an enlargement of the bowel thick. The second stage of the disease can last from 10 to 30 years after infection. The infection was more widespread in Latin America.
Important!Most of the simplest parasites enter the human body if basic sanitation and personal hygiene rules are not followed.
Infection routes
The penetration of any microorganism into the human body can occur through penetration through the skin or through natural openings. For most parasitic protozoa found in the environment, human infection methods are limited to the four most common:
- Contact and family. This route of infection becomes accessible to the simplest organisms, violating the rules of sanitation and personal hygiene. 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 entering a favorable environment, that is, inside a person. Infection can occur at any time: shaking hands, using other people's household items (towel, bed linen, dishes), washing hands with dirty water (in a lake);
- Fecal-oral (giardiasis). In this case, the infection occurs when the parasite leaves the intestine 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, get their hands dirty after playing in the litter box or with pets;
- Through contaminated food (toxoplasmosis). The meat of most animals, especially wild ones, can contain cysts of protozoan parasites, which, with insufficient heat treatment, enter the human body. Infection is also possible through dairy products that have not gone through sanitary control and raw fish without sufficient heat treatment;
- Communicable (malaria, sleeping sickness). Infection occurs by transmission of the pathogen through the carrier's saliva when bitten. The disease is transmitted by infected insects directly to a susceptible organism.
In addition to the main methods of infection, infection can occur in a number of other ways, which are much less common:
- Transplacental, with the penetration of parasitic protozoa 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 only occurs through sexual contact.
Prevention
The prevention of infection by protozoan parasites includes, first and foremost, compliance with all sanitation and hygiene rules. The exclusion of the possibility of infection by parasites can be reasonably achieved by following a series of recommendations:
- The heat treatment of meat, dairy and fish is sufficient (according to the thermal regime according to the technology). Special attention is given to products that have not gone through sanitary control;
- Carefully wash 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 protozoan parasite infection is suspected;
- Adherence to a sexual partner and refusal to use drugs;
- In the prevention of infection by insect bites, specific measures can be applied: use of medication, destruction of mosquitoes, mosquito nets and repellents, elimination of transgenic mosquitoes (resistant to malaria), creation of a vaccine.
Important!Of great importance in preventing any infection, including the simplest human parasites, is the body's level of resistance. After all, if a cyst enters into unfavorable conditions, where it lacks nutrition or immune system cells constantly attack a foreign object, the parasite will either die or leave the host's body.
There are several 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.
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 fruit, baked apples, vegetable oil, cooked vegetables. In the treatment of parasites, it is necessary to limit or completely exclude the products that cause fermentation processes: roasts and sugar.
Currently, the pharmaceutical industry offers many expensive antiparasitic drugs. However, its effective use can only be achieved in combination with preventive measures and adherence to a certain diet, the composition of which can be consulted by a qualified specialist.
Don't forget the time-tested, generational folk remedies. In case of a combination of all methods and methods under the supervision of a doctor, the parasites will have very little chance.
Conclusion
At the beginning of the 21st century, it is noted that humanity has achieved a lot in the development of parasitology. The message about a new discovery of a particular drug is always gladly accepted 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 like malaria, sleeping sickness, leishmaniasis and many others are rampant. And people hope and hope that everyone has the chance to live disease free.
Parasitic diseases in our time are relevant, they require social interaction in all spheres of human life, aiming at improving medical care to the population, observing the norms and standards of personal and public hygiene, carrying out preventive measures and sanitary and educational works, sanitation of natural foci of pathogenic organisms.
At the moment, in many countries of the world, several scientific studies are being carried out in the field of parasitology:
- development of scientific foundations and methods for monitoring infectious and parasitic infections;
- study of the biological characteristics and variability of the causative agents of the main diseases caused by parasitic protozoa;
- quality control and environmental safety of meat and fish products;
- conducting fundamental research to study the development of parasitic disease pathogens, their genetic variability, ecology.