Types of worms in humans and methods of infection with them

Worms are representatives of the lower worms that live in the human body. A disease associated with human infection with various types of worms is called helminthiasis. This disease is not rare and affects certain segments of the population. Children are susceptible to pinworm disease, hunters - trichinella, fishermen and fans of Japanese cuisine (raw fish in the form of sushi) suffer from diphyllobothriasis.

Many diseases, paradoxically, can occur in the human body due to helminthiasis. Today, the theory on the link between cancer and parasitic infections is one of the most relevant. In the presence of helminthiasis, symptoms do not always appear and if, nevertheless, patients with this disease experience unpleasant and uncomfortable sensations, they are perceived as signs of other diseases. The patient has been treated for years for pancreatitis, gastritis or colitis, without realizing that the cause of his illness is helminthiasis.

How does the infection occur?

Worms cause a lot of problems for humans

Helminth infection occurs as follows:

  • By unwashed hands
  • In contact with the ground
  • After insect bites
  • Because of dirty hands
  • By eating raw meat and fish
  • After eating unwashed fruits and vegetables
  • After contact with an animal
  • After contact with infected people

Mature parasite eggs can be found in soil, water, and food (raw and lightly cooked meat or fish). Rare cases of illness occur due to insect bites. The mechanism of infection with helminthiasis is oral-fecal. A person swallows parasite eggs with food and water. Contact and household methods of infection also occur. This happens when, after contact with earth or sand, the hands have not been washed thoroughly.

Vegetables and berries growing in the ground and not sufficiently washed are also a source of worm infection. Children who play with yard animals and pets are at risk of contracting worms. Animals that roam freely on the streets can bring helminth eggs into the house. Flies and other insects, after contact with animal feces, landing on food, can easily transfer helminth eggs. Surprisingly, person-to-person infection is also possible. It happens like this: a female pinworm can come out of the intestines and lay eggs directly on underwear, causing severe itching. A person, after scratching an itchy area, may come into contact with other toiletries and household items. These items fall into the hands of other family members, after which they become infected.

Water infection is also possible. Many parasite eggs easily fall into open reservoirs and wells. Drinking unboiled well water is extremely dangerous.

Types of helminthiasis

Helminthiases differ in the method of penetration into the human body:

  1. Biohelminths
  2. Geohelminths
  3. Contagious

Biohelminths are transmitted to humans through contact with animals. Soil-transmitted helminths can be infected through soil. Contagious ones occur due to contact with an infected person. The disease manifests itself differently depending on the method of infection, the number of worms and the degree of their adaptation in any human organ.

Stages of helminthiasis

Adult and helminth egg

The most destructive effect on the body is caused not by adults, but by their larvae. Adult individuals have already chosen a comfortable place in the human body, and the larva travels through the organs and leaves behind its lesions. The most common habitat for parasites is the gastrointestinal tract. Different types of parasites prefer different habitats. So, roundworms are found in the small intestine and pinworms take up residence in the large intestine and lower parts of the small intestine. Depending on the habitat of the parasites, helminthic infections are:

  • Translucent
  • Fabric

The luminals are located in the lumens of the genitals, and the tissues are located within the tissues. Depending on their growth, parasites can change habitat, moving from the luminal form to the tissue form. Helminthiases develop in two stages:

  1. Spicy
  2. Chronic

The acute phase lasts from a week to a month and the chronic phase continues until recovery. The acute phase begins with the introduction of the egg and continues as the parasite matures and grows. The disease manifests itself as allergic reactions to a foreign organism. In the chronic stage of the disease, various reactions of the body occur. During this period, the parasite moves throughout the body in search of shelter. The disease is accompanied by disturbances in the functioning of organs and systems of the human body. Integrated into the human body's immune system, parasites consume the substances necessary for their growth and development. This leads to metabolic disorders, digestive system disorders and difficulty absorbing vitamins and minerals.

In addition to this damage, parasites release their waste products into the human body, poisoning the body, leading to intestinal disorders, decreased immunity and the development of bacterial infections. Parasites contribute to the risk of developing cancer. This occurs due to the negative impact on the immune system and stimulation of cell division. Often a patient is examined by many specialists who discover many diseases in him. And in this case, all specialists can be replaced by a single doctor, a parasitologist.

Classification of helminths

Roundworms are quite common in the human gut.

Types of worms in humans:

  1. Flatworms
  2. Roundworms

Flatworms include:

  • Trematodes (opisthorchiasis, schistosomes, paragonimus)
  • Cestodes (large tapeworm, pork tapeworm, echinococcus, alveococcus)
  • Roundworms or nematodes:
    • Pinworm
    • Roundworm
    • Hookworm
    • Trichinella

This classification of helminths is presented in the medical literature. To successfully solve a problem such as helminthiasis, it is necessary to know in depth the features of the structure and life cycle of parasites.


Another name for trematodes is fluke. These parasites are shaped like flat or lanceolate leaves with two suckers. One suction cup is located in the mouth, and the second, which serves for fixation, is in the peritoneum. All representatives of flukes enter the body through an intermediate host. Most of these parasites are hermaphrodites.


This is a fluke - a worm up to 1. 3 cm long with two suckers. Opisthorchiasis is a hermaphrodite that parasitizes the liver, gallbladder and pancreas of humans and certain carnivorous animals (foxes, dogs, cats). Opisthorchiasis eggs pass out of the human or animal body in the stool. When these eggs enter a body of water, they are swallowed by freshwater molluscs, within which the larvae hatch and develop. The process of development and maturation of the larvae lasts two months. Then the larvae emerge from the mollusk and penetrate the skin of the carp. After six weeks, the larvae become fully-fledged mature parasites. Opisthorchiasis enters the body of an animal or person after eating contaminated fish. This worm can live up to 20 years in a living organism. Symptoms of opisthorchiasis:

  1. Allergy
  2. Weakness
  3. Headache
  4. Dizziness
  5. Depression
  6. Loss of consciousness

Damage caused to the body by opisthorchiasis:

  • Poisoning by parasitic waste
  • Damage to liver tissue
  • Damage to the gallbladder
  • impaired flow of bile
  • Inflammation of the pancreas
  • Secretory dysfunction
  • Decreased gastric motility
  • Thickening of the walls of certain organs, leading to the appearance of tumors.

The chronic course of the disease is characterized by:

  • Heaviness after eating
  • Pain
  • Vomiting
  • Nausea

Prevention of infection: To avoid infection with opisthorchiasis, you should not eat raw fish. The larvae die during heat treatment of products. Dried fish can only be eaten if it has been previously salted. Additionally, the larvae die when the fish is frozen for a long time.


Garlic is an effective anthelmintic

These parasites are of different sexes, similar to needles with a length of 0. 4 to 2. 6 cm. Females are longer than males and larger, producing 3, 000 eggs per day. The mode of reproduction is the same as that of the previous type of parasite, through freshwater molluscs. The larva enters the human body through the skin and mucous membranes while swimming in a body of fresh water. It can also enter the body of a person who accidentally swallows water while swimming. After a day of penetration, the larva transforms into an adult and enters the peripheral veins, through which it is sent to the lungs and venous vessels. There, the schistosome reaches sexual maturity.

Schistosoma lays its eggs in the intestines, mucous membranes and bladder. The eggs are then excreted from the human body in urine or stool and begin development again. Schistosoma lives in the human body for several decades, causing damage and infecting new individuals. The problems that arise when infected with schistosome are caused to the human body not by adults, but by their eggs. Only half of the eggs are excreted from the body, the rest accumulates in the organs. The eggs of this parasite have spines that damage a person's internal organs, often causing ulcers in the infected person. Patients with schistosomiasis have the following symptoms:

  • Appetite disorder
  • Anemia
  • Enlarged liver
  • Modified spleen
  • Decreased intestinal motility
  • Stomach ache
  • Constipation
  • Diarrhea
  • Weightloss
  • Intestinal bleeding
  • Pain during urination
  • Allergies
  • Weakness

When the genitourinary system is infected, patients experience:

  1. Menstrual irregularities and miscarriages in women
  2. Impotence and incomplete ejaculation in men

If eggs enter the central nervous system:

  • Acute cerebral schistosomiasis
  • Chronic brain damage
  • The death

Infected children experience stunted growth and development and a reduction in academic performance. Prevention of the disease includes avoiding swimming and walking barefoot in tropical waters.


Preventing worm infection - washing your hands

Paragonim is a 1 cm long lung fluke with an ovoid body and red spines. This parasite multiplies in the lungs of animals and enters the human body by eating crayfish and freshwater crabs. The parasite affects the respiratory system. Patients with paragonimiasis are characterized by allergic reactions and decreased immunity. Symptoms:

  • Temperature increase
  • Cough
  • Production of sputum from the lungs when coughing
  • Dyspnea
  • In severe cases, blood and parasite eggs are present in the sputum
  • Wheezing can be clearly heard in the patient's lungs

Prevention: Avoid eating raw crayfish and crabs.


Representatives of cestodes are tapeworms of different lengths. Some parasites reach gigantic sizes. On the heads of these parasites are suction cups, hooks or slits. Parasites need these devices to adhere to the intestinal walls. Cestodes affect the entire human body, they are more dangerous for children, who quickly develop anemia.


These parasites reach a length of 5 cm and are the causative agents of Echinococcus disease. The multi-chambered representative of this type of worm is the causative agent of a disease such as alveococcosis. The disease is transmitted by livestock and domestic animals. When caring for these animals, parasite eggs fall from their fur onto people's hands. When parasites enter the human intestine, they bite the mucous membrane. As the parasite matures, it develops 4 sections, the last of which is filled with eggs. These sections break off and spread throughout the body, infecting it. The fourth section disperses the eggs throughout the body.

The patient's infected organ, for example the liver, enlarges. Suppuration may form. An enlarged organ can even rupture the abdominal cavity. And this can lead to serious sepsis of the body and even death. Symptoms:

  • Weakness
  • Dizziness
  • Allergic reactions to parasite waste.

Echinococcus affects:

  1. Brain
  2. Spinal cord
  3. Eyes
  4. Thyroid gland
  5. Liver
  6. Lungs
  7. Uterus

This parasite can cause the formation of tumors, particularly malignant ones. The most unpleasant thing is that treatment of this disease is possible only through surgery. Prevention: personal hygiene in contact with animals.


These worms with elongated, round or cylindrical bodies most often parasitize the bodies of children. These roundworms include pinworms, roundworms and hookworms.


Giardia are also parasites!

They are small white worms. The length of the female is 1 cm, that of the male is 0. 5 cm. These parasites have a pointed tail, which is why they are called pinworms. The habitat of pinworms is the human intestine. The front end of the parasite has a suction cup with the help of which the pinworm enters the intestines, and the sharp end hangs into the lumen and damages the walls. This disease is called enterobiasis. You can become infected from a person through dirty hands. The disease is observed in preschool children attending kindergarten. A symptom of pinworm infection is itching near the anus. Most often, the itching is felt at night, when the female lays eggs, secreting a special substance. Symptoms:

  1. Itch
  2. Diarrhea
  3. Stomach ache
  4. Headache
  5. Lack of appetite

Prevention: hand washing.


These worms are the biggest. The length of the female can reach 0. 5 m, and she lays 200, 000 eggs per year, regardless of the male. The mechanism of infection is fecal-oral. Ascaris eggs enter the human body with unwashed fruits and vegetables, through dirty hands. The larva, entering the intestine, is selected in the shell and penetrates the intestinal walls, while migrating through the intestinal veins to the liver, through the hepatic veins to the heart, through the pulmonary arteries to the bronchi, then into the trachea and into the mouth. Some of the larvae die in the open air, the rest are swallowed. Symptoms:

  • Nausea
  • To vomit
  • Jaundice
  • Pancreatitis
  • Common acute respiratory infections
  • Bronchitis
  • Pneumonia


  • Hand washing
  • Wash vegetables and fruits
  • Maintain personal hygiene
  • Protect food from flies, cockroaches and other carriers.

In conclusion, we can say that the cause of the disease is not always bacteria and viruses that have entered the body. Parasites can cause enormous damage to human health. If unclear symptoms appear, the possibility of a parasite entering the body should not be excluded; the patient should consult a parasitologist.