The world health organization (who) reports that more than 4.5 billion people are infected with parasites. A parasite is an ancient representative of the natural world. According to recent reports, the parasites have existed on Earth even before the appearance of man: some holes on the skulls of tyrannosaurs, probably the result of infection by their parasites Trichomonas type that can leave scars on the bone tissues.
A variety of types of parasites that can exist along with the man and at his expense, raises some diagnostic and therapeutic difficulties.
Parasite (from the Greek para, about, and siton, food; παράσιτος, a parasite living at the expense of others) is a living organism that lives in (endoparasite) or on (ectoparasite) another organism. The parasite can be fixed, obligate, undergoes a complete life cycle, staying in a host (another organism), and to use it only on certain stages, the so-called temporary or facultative parasitism. Some parasites throughout the life cycle of the hosts, starting development in one body and ending in another. This means some parasitic organisms coexist with the host only in a certain period, changing owners or existing independently in the rest of the time, others start and end their life cycle in one body.
The phenomenon of parasitism observed on all levels of life. There are intracellular parasites, the simplest forms of multicellular parasites, parasites of plants, parasites that live inside or on the outer part of multicellular organisms.
The purpose of the introduction of the parasite is to obtain nutrients, security, obtaining the necessary development environment. Parasitic organisms can degrade the quality of life of the owner, to cause irritation, affect the dysfunction, ruin the fabric and also excrete toxins, contributing to the development of diseases. It is believed that the parasites evolyutsioniruet in the direction of decreasing harm to the host organism, thereby extending the opportunity to be at his expense.
In a separate category highlighted parasitoid: this is usually with two wings or Hymenoptera insects lay eggs in the bodies of animals or insects, providing the larvae with food. With the birth of the larvae of the host die, becoming food for new parasitoid. The activity of the parasitoid is characterized by a combination of parasitism and predation.
To this parasitoid include, for example, the emerald wasp stings causes partial paralysis and subordinate behavior of a cockroach. Then the wasp lays eggs in the body of the insect and carries it into the hole. The hatching larvae eat the cockroach. Some insects-parasitoid so to hone skills in parasitism that colonize the host and affect its behavior for a long period. The caterpillars of several species of organisms-the owners of the parasitoid Glyptapanteles (wasp-rider) protect hatched larvae from enemies, while acting as food for them.
Classic parasitism is a special case of symbiosis, the coexistence of two organisms. Such joint residence may be useful to the host and the parasite is harmful to one of the participants or process to happen without much influence. Between different forms of cohabitation, including parasitism, it is sometimes difficult to draw a clear line. For example, some forms of helminths reduce the sensitivity of the human body to allergens, at the same time causing harm and affecting conditionally positively on the health of the owner. Is also known as hirudotherapy, the use of leeches for medical purposes – an ancient form of treatment for various diseases, are used as one of the methods of alternative medicine in the modern world.
Unable to parasitize the bacteria, insects, plants, birds... for Example, cuckoo refers to a type of "nest or egg of a parasite", as it puts eggs in the nests of other birds. The same behaviour have some other types of birds and fish and insects. Certain varieties of plants, such as broomrape, are root parasites that grow on the roots of crops and which are powered at the expense of other plants. Famous chaga mushroom, used in medicine, parasite, growing on the trunk of a birch.
The numerous types of parasites – protozoa, helminths and insects. These parasites in the human body and on its surface are the most common.
Parasites in the human body can be quite varied: the simplest life forms, viruses, fungi, worms, bacteria. In accordance with the classification of viruses (intracellular parasites) and bacteria also belong to parasitic species, however, often speaking about parasites in the human body, referring to protozoa and helminths.
A long history of coexistence of man with helminths is confirmed by archaeologists: the earliest finds of helminth eggs in the feces of 5 date back to 900 BC. The written evidence has come down to us from Ancient Egypt: papyrus 3000 BC recorded data about the round worms, pinworms, tapeworm.
Hippocrates and Aristotle also paid attention to the presence of parasites in fish, raw meat, tracing the development cycle, for example, the pork tapeworm. The first mention of malaria belongs to the Emperor of China Qin-Shi-Huandi, who described the symptoms in 2 year 700 BC.
On the surface of the body and external organs of humans can be parasites, they are called parasites (Ectoparasite). Ectotrophic parasites – multicellular organisms, the most well-known blood-sucking insects (lice of different species, ticks), some species of leeches also belong to the Ectotrophic form of temporary parasites, which are found person.
The damage from the parasites in the human body can be quite diverse. The parasites, their eggs and waste products can carry out mechanical impact, clog capillaries, vessels, ducts of glands. Some are able to chew through the intestinal wall, damaging tissue. The most negative effect on health, causing violation of certain functions of the body in varying degrees.
For protozoal parasites include the simplest forms of life. Counted 17 species of protozoa that can cause disease in humans. They include such exotic for Russia species as Trypanosoma brucei, portable infected tsetse fly. Trypanosoma brucei causes sleeping sickness or African trypanosomiasis, characterized by confusion, sleep disorders. The disease is mostly found in the tropics of Africa, the Congo basin and Russia is very rare. Amoebiasis which is caused by dysentery amoeba, is the second death master human parasitic disease in the world, it affects every tenth inhabitant of the Earth. The most common is amoebiasis in areas with tropical climate and poor sanitary conditions.
Malaria is also caused by a parasite carried by infected mosquitoes. According to statistics, every year fall ill with malaria to 250 million people.
The most common in the world three types of protozoan parasites – the gout (disease giardiasis), Toxoplasma gondii (toxoplasmosis) and Trichomonas (trichomoniasis).
Giardiasis was first described by Dr. D. F. Lampler, which identified Giardia as the causative agent. In accordance with statistics from the world Health Organization, annually infection lamblia undergo about 200 million people on Earth. While sick with giardiasis long-about 500 million people.
In Russia, data show that on 100 thousand population clinical signs of illness in 90 people, but if to distinguish among ill children up to 14 years, among 100 thousand children giardiasis is diagnosed in 350. Thus, in Russia Giardiasis are more prone to children, the most frequently – ages 1 to 4 years.
Giardia has two forms: a movable, or vegetative, and form cysts. Infection occurs by ingestion of cysts that can persist in the environment (soil) up to 3 weeks, and in water up to 5.
Infection occurs most often in young children after licking dirty hands, along with household items, as well as in the use of vegetables, fruits, berries, not subjected to heat treatment. Extended also getting Giardia in the body along with the infected cysts water.
While in the body, moving from Giardia forms cysts in the vegetative and multiply in the small intestine, causing irritation. Special symptoms of giardiasis usually is not evident, limiting such signs, as a violation of stool (diarrhea, constipation), biliary dyskinesia, pain in the upper part of the bellies and the navel, nausea, atopic dermatitis, General malaise. Sometimes there is a lag in weight and height of the child.
When you move from small intestine to large intestine Giardia losing a favorable environment for breeding, again transformirovalsya into cysts and are released into the environment together with feces.
Treatment of giardiasis consists of a regenerative therapy for gastro-intestinal tract, funds from parasites of this species and enhance the immune system. Prevention of infection is good personal hygiene, handling products and before eating, drinking raw water exclusively in disinfected form.
The simplest single-celled parasite Toxoplasma gondii, which causes toxoplasmosis, responsible for the emergence of the myth that a woman during pregnancy not allowed to touch the cats – the baby will be born ugly.
Toxoplasma gondii parasite do that as a temporary host uses felines. Its reproduction is possible only in the intestine of these animals, and most of the groceries are cats. Toxoplasma eggs are excreted in the feces of an infected animal, and can get inside the body of other Pets and farm animals or humans through contact with feces, infected soil, eating raw meat. Toxoplasma gondii belongs to the kind of intracellular parasite, these eubacteria are one of the smallest parasites on Earth.
Cats are the primary host for Toxoplasma, an organism where the parasite spends most of its life cycle. In the bodies of other warm-blooded animals, including man, Toxoplasma gondii spend a short time.
Studies have shown that Toxoplasma gondii can affect the behavior of the infected animal. Thus, rodents with toxoplasmosis feel a little fear before cats: the parasite controls the behavior of rats and mice, "pushing" to the master transmission of Toxoplasma in the body where it can multiply.
The parasite multiplies in the tissues of heart, liver, eyes, brain. According to the world Health Organization (who), every third person is sick or ill with toxoplasmosis.
The disease occurs in several forms. In normal immune disease is easily tolerated is manifested by increase in cervical and axillary lymph nodes, periodic low grade fever, muscle aches, General malaise. A mild form of toxoplasmosis spontaneously without requiring specific treatment.
Chronic toxoplasmosis is accompanied by a change in the structure of the eye. The acute form is manifested in a rash, sudden deterioration of health that lead to exhaustion, can result in encephalitis brain. As a rule, to the development of acute toxoplasmosis are those with severe immunodeficiency.
Infection with toxoplasmosis during pregnancy leads to transmission of infectious agents through the placental barrier of the fetus. Toxoplasma in this case cause congenital toxoplasmosis in newborns, which leads to blindness, disorders of the Central nervous system, jaundice, abnormalities of skull bones, mental retardation. Congenital toxoplasmosis in children can occur immediately, symptoms may occur months or years after birth.
The man who was sick with toxoplasmosis develops immunity, defined by the presence of antibodies in the blood. If a pregnant woman has no history of the disease toxoplasmosis during pregnancy she is advised to eliminate contact with cat faeces and avoid places of possible accumulation of rodents.