Worms or helminths are parasites that live, feed, grow and reproduce in the human body, that is, they use it to implement their life cycle. According to various statistics, there are from 300 to 500 species of worms in the world that are dangerous to people. Its prevalence differs from country to country and depends on the level of health culture of the population and the socioeconomic development of the region. But even in enlightened European countries, symptoms of helminthiasis are found in a third of the inhabitants. Worm larvae can enter the human body in different ways, depending on their development cycle. The names of worms in humans, their varieties, as well as methods of infection, symptoms and methods of treating helminthiasis are relevant information for the majority of the world's population.
What types of worms are there?
Over many years of evolution, parasites have ideally adapted to live at the expense of other living beings, without raising suspicions in the immune system for a long time, so the symptoms of worms in humans do not appear immediately, and may be completely absent or lightly expressed.
Worms are able to penetrate the body unnoticed, camouflage themselves, destroy tissues and organs and poison the human body with toxins, living in it for a long time.
Some types of worms are only dangerous to humans, while others are parasites of animals. Their sizes range from microscopic to gigantic (15 or more meters in length). About three dozen parasites are common, including single-celled protozoan creatures. Among all the diversity, there are 3 main groups of helminths depending on the characteristics of their life cycle:
- Contact worms- found only in humans, they have a simple development cycle that does not require more than one host. Typical representatives are pinworms; These are the most common intestinal worms in children. Infection occurs in families, groups of children, public places through dirty hands, household items (toys, books, curtains, etc. ) on which mature eggs of these worms have fallen, as well as through inhalation of dust.
- Group of geohelminths– their eggs must first mature in soil, water or sand. They enter the human body through the mouth with unwashed fruits, vegetables, or herbs (such as roundworms and whipworms) or through the skin (such as hookworms).
- Biohelminths– have a complex life cycle with changing hosts. These worms appear in humans through ingestion of poorly washed vegetables or raw water (echinococcus), meat from animals contaminated with larvae (bovine or pork tapeworm), flattened fish and caviar (broad tapeworm), river fish (worms or liver flukes) or through the bloodstream (filariae).
Types of worms
All types of helminths are divided into 3 classes according to morphological features:
- Class of nematodes (roundworms)– roundworms, pinworms, hookworms, whipworms, trichinella. Roundworms are distinguished by the presence of separate sexes and have different sizes - from 1 cm (female pinworms) to 40 cm (ascaris).
- Class of trematodes (often called flukes)– Siberian worm (cat worm), schistosomes. They are always biohelminths and hermaphrodites, equipped with various suction and fixation devices in organs inside a person.
- Class of cestodes (type of flatworms)- These are long-stranded parasites. These include the broad tapeworm, pork tapeworm and bovine tapeworm - this is the largest worm, capable of growing up to 20 meters in length. Flatworms feed on the entire surface of the body, they are hermaphrodites and biohelminths. Echinococcus is considered the smallest representative of cestodes.
The goal of the worm world is great diversity and exceptional survival. The class of trematodes and cestodes are 100% parasites, but roundworms are heterogeneous, there are several tens of thousands of species, but not everyone likes to parasitize the human body. Most helminths lay eggs that can survive in the external environment for several months, and Trichinella is a viviparous individual.
In the human body, worms live not only in the intestines, some of them prefer to be located in the liver, lung parenchyma, brain, skin, muscle tissue and even in the eyeball.
Worms can be long-lived; for example, a cysticerci can live in the brain for many years; The growth of a hydatid cyst continues for up to 10 years.
About roundworms
Which worms are most common:
- Earthworms- live in the lower parts of the small intestine and throughout the large intestine of humans; females lay eggs around the anus at night, causing a characteristic sign of enterobiasis in humans - itching. The transmission of worms between people occurs through dirty hands (the eggs of these worms are often found under children's fingernails), bedding and household items. The eggs are very light and can be transmitted through the air with dust; remain viable for up to six months. These are the least toxic of the worms. Human feces do not contain them; for diagnosis, it is necessary to take a scraping from the perianal area.
- Ascaris- a large worm with a hook-shaped curved end; a mature individual can reach up to half a meter in length. The eggs mature in the soil and enter the stomach and small intestine with unwashed fruits, vegetables, or herbs. The released larvae gnaw through the intestinal wall, penetrating into the hepatic venous vessels, from there, with the blood flow, they rush to the lungs, the right part of the heart, sometimes to the brain and eyes, and inflammation develops in these organs. When coughing, sputum with larvae enters the mouth and is swallowed again into the gastrointestinal tract, where mature individuals develop, laying eggs after a month. These worms are brown or reddish because they sequester red blood cells. The lifespan of the roundworm is up to 2 years. For diagnosis, feces are tested for worm eggs.
- Whipworm- a worm as thick as a hair, about 5 cm long with a pointed tip, with which it clings to the inner surface of the intestinal wall. The eggs mature in the soil, where they penetrate the intestine, and here the larvae emerge. Whipworms feed on blood and like to remain inside the cecum and appendix, often causing inflammation and anemia. Life expectancy is about 3-4 years. To detect it, you need to test your stool for worm eggs.
- Trichinella- a small round worm that moves among predators and livestock. A person becomes infected by eating meat with larvae, in the intestine, after a few days, a mature individual of Trichinella is formed, which gives rise to live larvae. Through the blood, they can infect the entire body, but prefer skeletal muscles, where they remain for up to 5 years.
About tapeworms and worms
Which types of worms cause the greatest harm to the human body:
- Bull tapeworm (popularly called tapeworm)- is considered the largest human worm (up to 15-20 meters) with a ribbon-shaped body of thousands of individual segments, among which the most mature are in the tail and fall off as the eggs in them mature. These fragments are the size of a human fingernail, fall to the ground, grass and end up on the bodies of cattle. A person becomes infected through beef. The bovine tapeworm can live in a person's small intestine for up to 10 years and feeds on the entire surface of the body. For diagnosis, feces are examined.
- Pork tapeworm– similar to a bull tapeworm, but shorter in length. If a person is infected with larvae, the tapeworm grows in the small intestine; when infested with eggs, the larvae migrate and can infect any organ.
- Wide tapeworm– its type of worm is flat, more than 12 meters long. A person becomes infected by eating poorly salted caviar, dried or undercooked fish. It can settle in the small intestine for decades, constantly releasing mature segments with larvae into the environment.
- Echinococcus- the smallest parasite of the cestode class. Over the course of several years, their larvae form cysts, which can be located in various organs and reach 10 cm or more in diameter. Infection occurs in sick dogs or animals. The course is characterized by a pronounced clinical picture and the risk of complications.
- Feline fluke (liver)- a small worm that enters the human body by consuming undercooked freshwater fish, lives in the lumen of the small intestine, inside the bile and pancreatic ducts, can multiply quickly and live for up to two decades.
Despite the wide variety of species, it is possible to quite accurately determine which worm lives in the human body using modern diagnostic methods and the old proven test - feces for helminth eggs.
Treatment is carried out after confirmation of the diagnosis and prescription from the attending physician.