It is customary to call human parasites all organisms that live at their expense. These are bacteria, fungi, worms. Human parasites are divided into internal and external. The most unpleasant and causing the greatest amount of destruction of the body are helminths, a variety of parasitic worms.
Parasites and the human body
Creatures that parasitize on the human body can be external or internal. The exterior includes:
- Mosquitoes.
- Leeches.
- Lice.
- Microorganisms that cause scabies.
But there are many more creatures that prefer to settle inside the body. These include:
- Bacteria.
- The simplest.
- Helminths.
- Fungal.
The external and internal organization of the parasite belongs to the simplest. Due to the fact that they don't need to evolve to survive, their organization is greatly simplified.
There are many creatures that prefer to settle inside the body. For example, it can be bacteria.
They cannot survive without a host organism, as they are unable to get their own food. But they all multiply, almost without exception, very quickly, especially under suitable conditions. Where they are not immediately guided.
They differ geographically. Some can be found everywhere, no climate is a hindrance to them. Others live exclusively in tropical countries, but on the human body they can easily be carried to any other. In the body, they also settle in different places.
The luminal parasites are satisfied with the hollow parts of the body and those of the tissues live in the tissues.
The development cycles of parasites, mainly helminths, are also varied. Some develop first in the ground (biohelminths), then move onto a living creature. Others must first develop in the body of any other living creature, but not a person. Still others in an already adult state may be transferred to another or reinfected.
It is a mistake to assume that infection can only occur through dirty hands. Some helminth eggs are viable outside the nutrient medium for six months and adhere well to animal hair. Eggs also survive in a dangerous environment for them: if you cook meat or fish incorrectly, a whole brood of worms can settle inside you.
It is worth cooking the meat incorrectly, as a whole brood of worms can settle inside you.
Human endoparasites
Parasites are divided into endoparasites and ectoparasites. Endoparasites - those that live inside, ecto - outside. Endoparasites are able to settle in almost all internal organs and tissues of the body. They are divided according to localization. Endoparasites are:
- Endoparasite of internal organs that connect with the external environment.
They settle precisely in those organs that are connected with the external environment, not vice versa: the parasite organism does not choose to "breathe". These organs include the intestines, lungs, and the human urinary reproductive system. These are amoebas, worms and parasitic flagellates.
- Blood parasites.
They live in human blood. They can live in plasma, white blood cells, erythrocytes. These are trypanosomes, microfilariae or hemosporidia.
- Tissue endoparasites.
Those endoparasites that choose the tissues of the body as their place of residence. Muscle tissue, brain, cartilage, connective tissue. Even in nerve fibers, tissue endoparasite can settle. These are the Finnish tapeworms, trypanosomes, myxosporidia, trichina and others.
Endoparasites can choose the brain as their place of residence.
The definition of the type of parasite based on the place of its localization is rather arbitrary. Many species are able to migrate through various internal organs and travel regularly through the host's body. The reproduction process can take place in one place and organisms will exist and feed directly in another. The place where the parasite creature settles and will be considered the place of its conditional location.
Despite the simplification of many parasitic systems, their life cycle is quite complex.
Some species have to change several hosts during their life, which can belong to different biological species. Others are able to survive within a single species but may require intermediate hosts. In one person they multiply and in another they develop and mature. With such a complex life cycle, their sexual functions have significantly increased. To survive in the body, parasites must multiply quickly and a lot.
Helminths
There are three main types of helminths, also called worms. It:
- Roundworms, are roundworms.
- Cestodes, ribbon-shaped endoparasites.
- Trematodes, also known as flukes.
Geohelminths begin their existence in the earth's soil.
In addition, they can be divided according to the duration of the life cycle and the number of places they cross along the way. There are also three types:
Geohelminths
"Geo" is the earth. These worms begin their existence in the earth's soil, only after the maturation stage are they able to infect a person. They don't need intermediate guests; eggs enter the soil along with human feces. Up to the larval stage, they develop exclusively in the warm season.
Such worms include roundworms, intestinal eels, nekator, whipworms.
The larvae of these parasites can enter the human body through unwashed vegetables or direct contact with the soil.
Biohelminths
These are parasitic worms whose life stages pass through several hosts. There can be two or more intermediate hosts, depending on the type of worm. Some parasites change only one person. Others, before finally entering the human body, use the organisms of other biological beings for development.
You can get infected by pets or through contact with other people, as well as by eating half raw meat. Biohelminths include bovine tapeworm, echinococcus, broad tapeworm, trichina, and others.
Contagious worms
These worms need neither soil nor intermediate hosts. They go through all stages of their life cycle in an organism, located in a very comfortable position. The larvae are excreted directly from the human body, in contact with household surfaces and other people they spread freely.
Helminths can live in different organs and systems of the human body, periodically migrating from one part of the body to another.
The list of diseases caused by helminths is very large. It is possible to determine which parasites live in the body and which treatment can be started only after passing all the necessary tests to establish the type of test.
Round worms
The most common in the human environment are nematodes, also known as roundworms. In total, there are more than 24, 000 nematode species in the world.
The most common human nematodes are roundworms.
They are called round due to their shape, which is revealed if a cross section is made. The most common human nematodes:
- Ascaris.
- Pinworms.
- Trichina.
- Vlasoglava.
Helminth infestation, known as ascariasis, begins with direct contact with worm-infested soil or by eating unwashed fruits and vegetables. Parasites begin to develop in the intestine, then enter the human circulatory system, from where they go to various internal organs, making their way to the oral cavity. A person, without realizing it, again swallows an already adult parasite. They feed on the remains of undigested food. Ascaris waste products are extremely toxic. There is no vaccine for ascariasis; infection can only be prevented by observing the rules of personal hygiene.
Pinworm infection is called enterobiasis. These are small worms (5-10 mm) that attach themselves to the intestinal walls. They feed on blood and intestinal contents. They lay eggs under the skin, exiting the anus while the owner sleeps. Due to itching, a person scratches the anal area, the larvae get under the skin and on the hands, and can easily be transmitted to other people in the home or in public places. There are no painful symptoms in enterobiasis; it is extremely problematic to detect pinworm infection early on.
Trichinella, are also Trichinae, are nematodes that choose an animal or a person as their master.
Trichinella is a parasitic worm that infects the human body, causing the dangerous helminth disease trichinosis.
They begin to develop in the striated muscle area of the body, and then are redirected to the small intestine. In advanced cases of infection, there may be around 15, 000 Trichina eggs per kilogram of muscle tissue. These parasites are capable of causing a deadly disease, named for its source: trichinosis.
Whipworms are so called because of their appearance. The front of their small body is threadlike, with an esophagus located in it.
The back is wider, the rest of the internal organs of the parasite are located in it. The whipworm can be up to 50mm long. It feeds on blood and tissue fluids. Trichocephalosis causes the disease.
Tapeworms
There are about 3, 500 species of tapeworms known worldwide, also called cestodes. These flatworms have no digestive system at all, and the diseases they cause are called cestodosis.
The most common cestodoses:
Cysticercosis
The disease is caused by the larvae of the pig tapeworm, which penetrate through contaminated food, from dirty hands.
The disease affects the skin, bones, internal organs, brain and spinal cord. Most often, parasites are sent to the brain (in 60% of cases of infection). It is diagnosed based on the appearance of rounded formations on the skin. The disease is treated; in case of central nervous system infection, the prognosis can be poor.
Echinococcosis
It is localized in the liver, lungs and many other internal organs. Echinococcus larvae excite the disease. They can develop within a person over the course of several years.
Infection occurs through contact with animals, collecting berries and fruits, drinking contaminated water.
The course of the disease is not too obvious, it can develop over the years and turns out to be detected only by chance.
Alveococcosis
Alveococcosis is caused by the larvae of alveococcal worms. The disease is similar to echinococcosis, but it is more severe. It affects the lungs and kidneys. Without treatment, the disease is very likely to be fatal due to the development of liver failure.
Alveococcosis most often affects the kidneys.
Teniarinhoz
Teniarinhoz is caused by a bovine tapeworm. Parasitic tapeworm in the area of the human small intestine, develops over a period of 2. 5-4 months. The prognosis for treatment is often favorable. Parasites can get into a person with raw or insufficiently heat-treated infected meat.
Tapeworms are very prolific. They have the least remaining sensitivity and no digestive system. Such parasites cannot develop without a host.
Fluke worms
Flukes are flukes. These are flat, body-shaped worms that resemble an oblong tree leaf.
Some species of flukes can be up to one and a half meters in size.
And they end up in the human body most often through fish or other seafood. About 7, 200 species of flukes are known, 40 of which inhabit humans and cause flukes, a serious disease caused by an infection.
The most common flukes:
Liver fluke
Globally distributed, it can exist in animals and humans. The biological life cycle is complex, the parasite changes host.
The most common fluke is the liver fluke.
Schistosoma
Schistosome larvae can penetrate the skin or mucous membranes. The life cycle is complex, they feed on blood. A female is capable of producing about 3000 eggs per day, the fertility of these parasitic worms is very high.
Other liver flukes
They cause opisthorchiasis, a helminth disease that spreads mainly to the liver. They have a toxic effect on the human body.
The digestive system of fluke worms is well developed, and with it the reproductive and excretory system.
The rest of the systems are developing poorly. The flukes feed on blood, skin epithelial cells, and intestinal contents. They can live almost anywhere: from the liver to the conjunctivial sacs of the eyes.
Other types of endoparasites
The rest of the internal parasites are a variety of bacteria that cause dangerous diseases, and with them the simplest microorganisms. The fungus that spreads inside the human body also belongs to the endoparasite section.
Many beneficial and harmful microorganisms live in the human body. Some of them cause quite dangerous diseases that can lead to death. It is not always possible to immediately recognize the presence of parasitic creatures within it, but early detection of the infection offers greater possibilities for a complete cure. If an invasion is suspected, it is recommended to promptly undergo a comprehensive examination by a doctor.