Parasites are organisms that exist and provide for their needs at the expense of the host and that cause diseases and pathological conditions in themselves.
Parasitic invasion has long been known and, despite advances in medicine, is common among humans and animals today. Almost everyone, at least once in his or her life (especially in childhood), suffers from a parasitic disease.
A large number of chronic diseases of various organs and systems, including allergic reactions and autoimmune processes, which can be triggered by parasites, are associated with the widespread spread of parasites.
Among the parasites, there are many types - they can be microscopic and reach a length of 10-14 m. They are united by their lifestyle, as well as the following characteristics:
- High ability to reproduce.
- Constantly improving the mechanism of distribution and adaptation to life in the body of the host, human or animal.
What are parasites?
- The simplest parasites are unicellular organisms.
- Helminths are multicellular parasites, including worms:
- flatworms (liver, cat and other flukes);
- ringworm (pinworm, roundworm, whipworm, etc. );
- tapeworms (beef, pork and tapeworms, tapeworms, etc. ).
- Arthropoda are parasites belonging to ectoparasites, characterized by external chitinous skeletons, segmented bodies and limbs.
Terrible simplicity and unattractive appearance
Many single-celled organisms cause diseases that affect both humans and animals. The simplest parasites include: amoeba, leishmania, giardia, plasmodia, toxoplasma. Among them, the most common causative agent that causes parasitic invasion is Giardia. The doctor's opinion about this unicell is still double. Some consider Giardia completely harmless, others blame them for many, if not all diseases of the host organism.
There are also protozoa that, once in the body, do not cause the invasion of moist parasites, but life -threatening diseases such as malaria, leishmaniasis.
The definition of fleas, ticks and ticks as ectoparasites of animals and humans is due to the fact that they are on the surface of the skin. If the pathogen is not infected with any disease and does not tolerate it, then it can cause discomfort to the patient simply by its presence on the body. By themselves, they do not cause significant harm to the body.
Next, we will talk about helminths, as there is much controversy about the timely detection in the body and treatment of this particular group of parasites, interest in helminthic invasion is driven by advertising that encourages people to seek and find symptoms and diseases that may not exist.
One parasite, one host?
Parasites can have one or more hosts. In the latter case, one of them is intermediate - an animal or a person in his body an intermediate phase of parasitic development occurs, associated with asexual reproduction. For most parasitic species, the presence of an intermediate host is essential for survival.
Macroorganisms in which the final phase of parasite development occurs - the stage of sexual reproduction, called the end.
Biohelminths, in order to go through the full cycle of their development, have to visit multi -species organisms, and some helminths do not undergo any changes in the body of the intermediate host - these are called geohelminths.
How can you get sick?
Infections can occur in a variety of ways. This can be the intake of parasitic breeding material (cysts, eggs, larvae) as a result of eating contaminated food or water, as well as as a result of violation of hygiene measures - from dirty hands, in close contact with pets. (children often experience this). Less commonly, you can get parasitic diseases by inhaling eggs or pest cysts with dust. Among helminths there are those whose larvae can penetrate into the body of an animal or a person directly through the skin, such as tapeworms, the causative agent of ankylostomiasis, which can be infected by walking barefoot.
The spread of parasitic infections is facilitated by both climatic and social factors, which include poor levels of hygiene and sanitation education of the population, violations in the hygienic processing of certain products, as well as dietary habits. For example, where the consumption of meat of domestic or wild animals that do not pass sanitary and veterinary controls is widespread, high levels of trichinosis disease remain.
Habitat in the host body
Parasites affect almost all organs and tissues. It all depends on what conditions are needed for survival at a certain stage of the life cycle. Depending on the localization, helminthiases are divided into tissue (extraintestinal) and luminal (intestinal).
The first includes trichinosis, toxocariasis, echinococcosis. At the same time, in the host body, the parasite is introduced into the internal organs, and this form will be called visceral. And also for most pathogens, specific damage to specific organ systems or separate target organs is characteristic.
For example, Toxocara geohelminths, the causative agent of toxocariasis, affect the organs of vision, especially among school-age children. At the same time, there is no significant change in the general condition, there is only a decrease in acuity and partial loss of the visual field, strabismus may develop. Such manifestations usually develop over several months. An important feature is that only one eye is always affected. With efficient and careful ophthalmological examination, timely detection and definition of the disease is possible.
Luminous helminthiases include trichuriasis, ascariasis, opisthorchiasis, fascioliasis and others. These helminths are located in the lumen of the hollow organ.
For most species of helminths, the common habitat is the digestive system, which is one of its departments.
So, whip worms live in the large intestine, ringworms live in the thin top, and pygmy tapeworms live in the bottom.
What determines the nature of disease progression?
- How parasites enter the host body.
- parasite population density.
- The degree of adaptation to the human or animal body.
- The condition of the host organism (strength of immunity, presence of concomitant pathology).
Manifestations of parasitic infestation
At the onset of the disease, the response of macroorganisms is due to the entry of foreign antigens and the response of the immune system to them. In many cases, an unmotivated fever occurs, according to the sick person, which can last more than a week with periodic improvement in the condition. Depending on the localization of the parasite in the body, other symptoms appear, among which there may be loss of appetite, belching, nausea, abdominal pain, stool instability, diarrhea, yellowing of the sclera and skin, discoloration of urine and feces. . When pests are found in the lungs, manifestations resembling bronchopneumonia or bronchial asthma are possible. From the side of the nervous system, seizures, paresis, paralysis are not uncommon.
In the chronic phase of parasite invasion, metabolic disorders often manifest themselves, as the pathogen feeds at the expense of the host and consumes its nutrients. Absorption in the digestive system is often impaired in affected animals or people. The affected organism is depleted, anemia, manifestations of beriberi may appear.
In addition, pathogens poison macroorganisms with products of their vital activity, causing symptoms of intoxication in the host.
Parasitosis may not present with acute symptoms, but has a slow and protracted course, often with long -term compensation. And only when the defenses of the affected organism are depleted, alarming symptoms will appear.
Interaction with affected organisms
Helminths, among other things, have a remarkable effect on the immune system of the host organism, which means that the latter becomes more susceptible to various infections, its recovery will come later and the course of the disease will be more difficult than the healthy ones.
The effects of parasites on children's bodies are very detrimental. Children become nervous, fickle, their sleep is disturbed, they get tired quickly. Delayed physical and mental development. Perhaps the appearance of allergic diseases, the corresponding pathological course worsens.
Despite the serious condition, parasite invasion only leads to death in further cases, because the parasite depends entirely on the host, its death to the pest is most likely fatal, so the organism of the affected animal or person becomes weak. by parasites, but not killed.
Parasite invasion may not manifest itself in any way or manifest itself very brightly. Timely understanding and establishing a correct diagnosis is a task that can be performed only to be with doctors and patients, this disease can be very dangerous.