Not everyone knows the dangers of helminths in the body, the types of worms and how they infect people.Some parasites can live in the human body without any problems.Up to 90% of adults and children do not even suspect that they are infected with worms.Helminths are of great medical importance because they can be transmitted from person to person and lead to dysfunction of internal organs.
The most common types of helminths
Worms in humans are parasitic worms that live in organs and live at the expense of their host.There are several hundred species of them.In some countries, laboratory tests can only detect part of it.The following types of worms are distinguished:
- nematodes (roundworms);
- cestodes (tapeworms);
- Trematodes (leeches).
There are lumen and tissue parasites.The first are characterized by the fact that they live in the lumen of a hollow organ (intestine, bile ducts).Human tissue worms live in the thickness of tissue.There are worms that belong to two groups at once.These are roundworms.Adults live in the lumen of the small intestine and larvae can infect the lungs and liver.
The classification of helminths includes the division of worms not only by habitat, but also by features of the life cycle.To fully develop, some parasites require intermediate hosts (molluscs, fish, animals) in which the larvae mature.Such worms belong to the group of biohelminths.Some parasitic worms need to be exposed to the external environment (water or soil).This is how geohelminths develop.
Contact types of helminthiasis are identified separately.These include hymenolepiasis and enterobiasis.Infection with pinworms and dwarf tapeworms is possible through contact with a sick person.There are intestinal and extraintestinal worms.The first group includes pinworms, roundworms, tapeworms and whipworms.Other parasites (Fasciola, leeches, echinococci, trichinae, alveococci) affect other organs.
Helminths from the group of nematodes
Different types of helminths are known.The most common are roundworms (nematodes).They belong to the type of protocavitary worms.Human nematodes are arranged as follows:
- have a body that is not divided into segments;
- in different sizes;
- threadlike or fusiform;
- have a skin-muscle bag and a cuticle;
- have a digestive system in the form of a through tube;
- dioecious;
- capable of laying eggs.
Most often, the presence of these worms in humans is manifested by gastrointestinal disorders.The most common nematodes that parasitize the human body are pinworms, roundworms, hookworms (hookworms and hookworms) and whipworms.According to WHO, more than 1 billion people suffer from enterobiasis.Young children are more likely to become ill.
A person can become infected with pinworms anywhere.This is due to the wide distribution of the eggs of these helminths.Transmission factors include toys, household items, pens, pencils, unwashed food, dirty hands, bus railings and telephones.Of all helminth species, pinworms are the most frequently detected.
These parasites reach 1 cm in length and have a thin body with a sharp end.They are attached to the intestines.Small children who attend kindergarten are more likely to become ill.Pinworms live in the human body for 1-2 months.A person can become infected not only with enterobiasis, but also with ascariasis.These diseases are often diagnosed at the same time.Roundworms are larger (20-40 cm).
These are geohelminths whose eggs develop and remain in the ground for a long time.The method of infection is oral.This happens through contact with the soil, drinking untreated water, or eating vegetables and fruits contaminated with feces.Worms such as whipworms are very often detected.This is the causative agent of trichuriasis.They have a thin body that resembles hair.The parasite's back is thickened.
These helminths reach a size of 55 cm.They parasitize the colon.Up to 30% of the population is infected with hookworms.These are geohelminths that are particularly widespread in countries with warm climates.They are also called crooked heads.These worms are only parasitic on humans.Their body length reaches 14 mm.Hookworms can live up to 15 years and hookworms can live up to 8 years.
Representative of tapeworms
Doctors often have to deal with tapeworms.They are called cestodes.The peculiarity of this type of worm is that its body is divided into segments.This group includes various tapeworms (dwarf, bovine and pork tapeworms) as well as the broadband worm.The pathogen causing hymenolepiasis is often detected in children under 14 years of age.This is a dwarf tapeworm.
This type of helminth has the following distinctive features:
- up to 5 cm tall;
- parasitizes mainly in the intestines;
- has a head (scolex), neck, body (strobilus), 4 suckers and hooks;
- divided into segments;
- develops completely in the human body.
Along with pinworms, the dwarf tapeworm is one of the contact worms.Parasite eggs can be spread by insects (flies).There are species of cestodes that reach 20 m or more.A prominent representative is the broadband worm.This is the causative agent of diphyllobothriasis.This worm belongs to the group of biohelminths.
To complete its life cycle and become an adult, it must invade the body of intermediate hosts (fish and crustaceans).The peculiarity of this parasite is that its long stay in the human body leads to persistent anemia due to a lack of vitamin B12.Diphyllobothriasis most often affects people who love fish.These parasites infect people who live and fish near freshwater bodies.The broad-spectrum worm can live in the human intestine for 20 years or longer.Animals (cats, dogs, bears) can also act as definitive hosts.
An infection with worms called echinococci often occurs.They live in the human body in the form of larvae.Humans are intermediate hosts and at the same time a dead end in the development of helminths.Infection occurs through consumption of meat from contaminated game or domestic animals, as well as unwashed vegetables and fruits.Echinococci are unilocular and multilocular.
The latter are called alveococci.These cestodes are most commonly located in the liver and lungs and form cysts.These are vesicles with a liquid substance and scolexes (heads) of the parasite.Massive liver damage can result in tissue compression.If the cyst membrane ruptures, there is a risk of shock.There are other types of helminths from the cestode group: bovine and pork tapeworms.They are the causative agents of taeniasis and teniarynchosis.
Worms from the group of trematodes
Only doctors know what worms are.Leeches (leeches) are very common.These include schistosomes, fasciolas and cat flukes.These types of helminths have the following characteristics:
- small size;
- equipped with suction cups;
- leaf-shaped or round (except schistosomes).
The following groups of leeches are distinguished:
- Blood;
- hepatic;
- pulmonary;
- Colon.
These parasites most commonly attack organs other than the intestines.Infection with worms such as schistosomes can cause damage to the urinary tract (kidneys, bladder), liver, and other organs.More than 300 million people are infected with schistosomes.These are small (up to 2 cm) parasites with an elongated body.Men get sick more often than women.
Schistosomes affect veins, kidneys, bladder, ureters and abdominal organs.They feed on blood.Schistosomes are biohelminths.They develop in the bodies of freshwater mollusks.Their peculiarity is the ability to actively leave the vessels and be excreted into the environment with metabolic products (urine and feces).Schistosomiasis causes cystitis, anemia, lymphadenopathy, and damage to the liver, kidneys, and genitals.
The rare types of parasites in the human body include Fasciola (liver and giant leeches).Some individuals reach 10 cm in size.People become infected through diseased herbivores through the food route, by eating salads and vegetables that grow near standing water.Raw water can also be a transmission factor.
Fasciolas are hermaphrodites.They affect the biliary tract and lead to the development of cholestasis and liver fibrosis.In severe cases, hepatitis or cholecystitis occurs.One of the endemic human helminths is the cat leech.It causes opisthorchiasis.The reason is the consumption of infected fish.
Meat-borne worms
Not everyone knows what types of worms are transmitted through meat.This group includes worms such as beef and pork tapeworms, echinococci and trichinella.A pathology such as trichinosis can have serious consequences.This is a disease caused by small roundworms.Trichinella enter the human body through food.
The following products are dangerous:
- kebabs;
- game (bear meat, wild boar);
- Pork;
- homemade sausage;
- homemade lard;
- steaks and medium-cooked meats;
- Bacon;
- brisket;
- Ham
It is not recommended to eat meat from walruses, seals and nutria.Those at risk include hunters, tourists, ranchers and people who cook meat poorly or undercooked.Trichinosis is characterized by a severe allergic reaction, edema syndrome and muscle damage.In severe situations, death is possible.
Meat is a factor in the transmission of beef and pork tapeworms.People become infected by eating pork or beef that contains the helminth.This is an intermediate form (larval form) of the development of the parasite.Adult pork tapeworms reach a length of 4 m, and bull tapeworms - 20 m.
The following risk factors for infection with taeniasis and taeniarinhoz are identified:
- lack of veterinary supervision;
- poor heat treatment of meat;
- livestock breeding (cows, pigs);
- unsanitary conditions;
- Infection with cysticerci of water.
Most often only one adult tapeworm lives in the intestines of sick people.Nevertheless, the parasite can cause indigestion and intestinal obstruction.The presence of these helminths in humans can be detected by stool examination.A distinctive feature of the beef tapeworm is that its segments crawl out and can actively move during defecation.
Herbivores themselves become infected by eating grass contaminated with the feces of sick animals.Cysticerci are formed in the bodies of farm animals (pigs and cows).They are easy to spot when buying and cutting meat.They are round in shape and yellow in color.A person infected with beef tapeworm does not pose a threat to others.
Helminths are transmitted by fish
There are different types of worms that can be infected by eating undercooked or undercooked fish.The human body needs different products.Millions of people around the world consume freshwater fish, caviar and milk.You are at risk of developing diphyllobothriasis and opisthorchiasis.
In some regions, tapeworms and cat flukes are endemic helminths.The reason is active fishing and infection of fish.Up to 75% of the population is infected with opisthorchiasis.These parasites also affect animals (cats, foxes, dogs).Infection occurs when eating semi-raw fish (carp, bream, roach, fish) infected with parasite larvae.
Risk factors include rapid frying of infected raw materials, consumption of lightly salted, dried or raw fish, caviar and kebabs.The mechanism of infection is nutritional.The cat leech belongs to the group of leeches.This helminth is no longer than 2 cm.These worms cause bile stasis, inflammation of the pancreas, hepatitis and dyskinesia.
If left untreated, the likelihood of developing cancer and liver cirrhosis increases.Fish can cause diphyllobothriasis.This is a cestodose caused by the broad tapeworm.Infection with these worms occurs when infected fish are consumed from freshwater bodies.The most dangerous are ruffe, pike, perch, zander and burbot.These are all predatory fish.The second intermediate host of the tapeworm is crustaceans.
These helminths live in the small intestines of humans and some animals that feed on fish containing tapeworm larvae.In contrast to the pathogen that causes opisthorchiasis, this helminth attacks the intestine and leads to atrophy of the mucous layer.Anemia often develops.Diphylbothriasis mainly affects adults.The risk group includes people whose family includes fishermen and lovers of dried and lightly salted fish.
Worms that infect the skin
There are helminths that affect the skin and soft tissue.Guinea worm (the causative agent of dracunculiasis) belongs to this group.This is a nematode with a size of up to 120 cm.It affects the subcutaneous tissue and the intermuscular tissue.A person becomes infected by drinking dirty water or swimming.Parasites invade the intestines and then the subcutaneous tissue.
When the helminth becomes sexually mature, it secretes special substances that attack the skin.An ulcerative defect forms at this point through which the parasite removes the larvae.This happens upon contact with water.Such patients experience severe itching.Guinea worm is more common in tropical countries.The intermediate hosts are cyclops (freshwater crabs).
There are worms that can penetrate human skin on their own when they come into contact with water.This also includes intestinal acne.The main mechanism of infection is percutaneous.The larvae of the parasite damage the skin and enter the blood.Risk factors for infection include walking on the ground with bare feet, swimming in dirty ponds, and performing agricultural work.
How to get rid of different types of helminths
A doctor should treat patients after conducting laboratory and instrumental studies.The antihelminthic drug is selected depending on the type of worms.
Many drugs kill various types of helminths and remove them from the body.Doctors almost always prescribe broad-spectrum drugs, since even after identifying parasite eggs in the stool, it is very difficult to determine their type.
If an infectious person (with hymenolepidosis or enterobiasis) lives in the same apartment with another person, examination and treatment of these people is necessary.
For each anthelmintic there are not only indications, but also contraindications.
Drug treatment alone is not enough.Some types of parasitic worms require surgery.In cases of echinococcosis, cysts are removed.Surgery is also required if there are parasites in the heart and brain.Some helminths require sanitary and hygienic measures.
They are carried out after treatment and while taking medication.To get rid of pinworms, you need to change, wash and iron your underwear daily, wear tight swimming trunks, wash the floors and wipe all household items.
Therefore, there are a large number of different parasitic worms that live in the human body.