Helminths: what are the dangerous parasitic worms for humans

According to the WHO, one in two people on the planet is infected with helminths every year. Many people think that parasitic worms are not very harmful to health. However, not everything is so simple: helminths can infect important internal organs - heart, lungs, brain.

Helminths: who are they?

Helminths are parasitic worms that can choose the body of a person, an animal, a plant as a host. There are three classes of helminths in total:

  • tapeworms.This class includes about 3, 5 thousand types of helminths. The length of the parasitic worms varies from a few mm to 10-15 meters;
  • flukes.Parasites got their name from the presence of suckers, with the help of which they receive nutrients. The human body can infect about 4 dozen species of flukes. As a rule, the length of the worms does not exceed 5 cm;
  • round worms.This class of helminths has more than 24 thousand species. Nematodes are spindle-shaped. Usually their length is no more than 0. 5 meters.

You can get infected with helminths in various ways. However, most of the time parasitic invasion occurs for the following reasons:

  1. Poor hand hygiene.
  2. Unwashed vegetables, fruits; undercooked or undercooked meat, fish - the use of such products increases the risk of parasite infestation many times over.
  3. Keep open food out of the refrigerator. Insects are able to transfer helminth eggs to foods that are stored without packaging.
  4. Contact with pets.
causes of parasite infection of the body

The main symptoms of the presence of parasites in the body:

  • nausea, vomiting, diarrhea;
  • weight loss;
  • allergic rashes;
  • swelling;
  • itching in the anus;
  • grinding your teeth in a dream.

What helminths are most common in Russia? Consider the most common types of parasitic worms and the diseases they cause.

Tapeworms

The body of the tapeworm consists of members, the total number of which varies from 3 to 5000. The main fixing element of the helminth is the head, additional ones are suckers, hooks.

The most common causes of tapeworms are:

  • diphyllobothriasis;
  • teniarinhoses;
  • teniasis.
tapeworm, a parasite of the human body

Diphyllobothriasis

The causative agent of the disease is a large tapeworm affecting the human intestine. The development of worm eggs occurs in fresh water. The scheme of the tapeworm entering the human body is as follows:

  • The worm's eggs are swallowed by crustaceans living in the basin.
  • Infected crustaceans are eaten by fish.
  • A person becomes infected with a parasite by eating fish that has undergone insufficient heat treatment.

The symptomatology of the disease develops 1, 5 months after infection. The main sign of the pathology is the presence of whitish fragments of helminths in the feces.

By attaching itself to the intestinal mucosa, the tapeworm absorbs a large amount of vitamin B12. For this reason, people with diphyllobothriasis often develop anemia. In addition, tapeworms can cause an increase in the liver, spleen, intestinal obstruction.

Teniarinhoz

The causative agent of the disease is the bovine tapeworm, which lives predominantly in the human small intestine. During its development cycle, the helminth replaces two hosts: the intermediate is cattle, the main one is man. Bovine tapeworms can live in the body for 20 years, multiplying and causing damage to health.

Typically, people develop teniarine after eating undercooked or undercooked beef.

The disease often proceeds without pronounced symptoms and is detected by chance when a person sees elements of helminths in his feces. In some people, in addition to the main signs of helminth infection, pain syndrome on the right side of the anterior abdominal wall may occur.

Adult helminths are able to penetrate the appendix, pancreatic duct, biliary tract, causing acute inflammatory processes in them. With multiple parasitic infestations, intestinal obstruction can develop.

bovine tapeworm parasite

Teniosi

The causative agent of the disease is the pig tapeworm, which initially affects the human small intestine. Human infection occurs through the consumption of raw or improperly cooked pork.

The parasite can penetrate various organs and tissues, causing pain in the abdomen, back, limbs. The pathology is more favorable when the worm is localized in the subcutaneous adipose tissue and in the skeletal muscle tissue. When worms penetrate the eye muscles, they cause a decrease in visual acuity, lacrimation and photophobia. The defeat of the pig chain of the brain can be fatal.

Suckers

The flukes are leaf-shaped and have a high ability to reproduce in different periods of the life cycle. Reproduction of worms is possible not only sexually with fertilization, but also without it. In addition to suckers, worms have many hooks and thorns, thanks to which they reliably attach themselves to the mucous membranes of organs.

kind of fluke parasite

Common diseases caused by flukes:

  • fascioliasis;
  • opisthorchiasis;
  • paragonimiasis.

Fascioliasis

Fascioliasis occurs when the liver or gallbladder is damaged by the liver fluke. Basically, infection occurs when eating vegetables, for which water was used from open reservoirs.

In addition to the standard signs of parasitic infection, a person may experience asthma attacks, which are accompanied by shortness of breath, flushing of the face, dilated pupils, and rapid heartbeat. If an adult has caused obstruction of the bile ducts, obstructive jaundice develops. Signs of pathology:

  • cramping pains in the right hypochondrium;
  • yellowing of the skin;
  • temperature;
  • colorless stools.

Opisthorchiasis

The causative agent of the disease is feline fluke. The name of the parasite is due to the fact that, in addition to humans, it often infects cats and other mammals that eat fish.

parasitic feline fluke

As a rule, the feline fluke affects the liver and pancreas, causing inflammation in the organs. Symptoms are varied and depend on the number of parasites. The patient may experience:

  • symptoms of intoxication;
  • temperature;
  • urticaria;
  • itchy skin;
  • pain in muscles, joints, right hypochondrium.

In some cases, helminths cause an increase in lymph nodes, the development of jaundice. The chronic form of the pathology often leads to hepatitis, liver cirrhosis.

Paragonimiasis

The culprit of the disease is a pulmonary fluke, which enters the human body with infected crustaceans.

First, the parasite enters the human intestine, then into the abdominal cavity. The end point of his journey is lung tissue. In addition, the worm is able to penetrate the brain and affect the central nervous system.

parasitic lung fluke

Specific signs of parasitic invasion of the lungs:

  • chest pain;
  • cough with phlegm, which may contain pus and blood;
  • temperature.

In some cases, helminths cause a violation of the ventilation function of the lungs and gas exchange when breathing.

Round worms

Due to their structure, nematodes (roundworms) are able to survive even in extreme conditions. Their body is covered with a three-layered musculocutaneous sac, which reliably protects parasites from external influences.

type of parasitic nematodes

Common diseases caused by roundworms:

  • ascariasis;
  • enterobiasis;
  • trichinosis.

Ascariasis

The development of the disease provokes ascaris, which is initially fixed in the small intestine. The average length of adults is 40 cm. The larvae of the parasite can enter the human digestive system with unwashed fruits and vegetables, contaminated water. Also, poorly washed hands before eating are often the cause of ascariasis.

During the penetration of the larvae into the human body, a subfebrile temperature, allergic rashes and a cough with release of clear sputum can be observed. Signs of the intestinal stage of ascariasis (diarrhea, abdominal pain) are observed only in the presence of several parasites. As a rule, living in the intestines of a worm is asymptomatic.

Complications with multiple parasitic infestations:

  • blockage of the bile duct;
  • purulent inflammatory processes in the gallbladder, liver;
  • inflammation of the appendix;
  • intestinal blockage.

Enterobiasis

The provocateurs of the disease are pinworms - small worms up to 1 cm long. Helminths penetrate the human digestive system in the same way as roundworms.

parasites of human pinworms

Currently, enterobiasis is the most common parasitic pathology in the world. Basically, the disease is diagnosed in children under the age of 10.

Symptoms, as in previous cases, only develop with multiple parasitic infestations. Children often have diarrhea, mucus in the stool, difficult and painful digestion, itching in the anus and nausea. With a severe course of the disease, cramps in the limbs can occur. In addition, pinworms are able to penetrate the genitals, causing acute inflammation in them.

Trichinosis

This disease causes Trichinella, one of the smallest parasitic worms. The length of the parasite rarely exceeds 4 mm. In the larval stage, worms can infect skeletal muscles. The exception is the myocardium, the muscle tissue of the heart. Adults parasitize the small intestine.

As a rule, human infection occurs when eating half-cooked pork. At the same time, for the development of the disease, it is enough to consume only 30 g of meat affected by parasites.

The pathology manifests itself with the standard symptoms of parasitic invasion. In an advanced stage, swelling of the eyelids, face, arms and legs, pain in the lower back, chewing muscles may occur. Possible complications are total or partial loss of mobility, paralysis of the airways.

How to avoid helminth infestation?

To reduce the risk of becoming infected with parasitic worms, it is important to follow these guidelines:

  1. Wash your hands thoroughly before eating, after visiting the street, public places.
  2. Observe the correct technology for cooking meat, fish. Heat treatment of meat and fish products should take at least 20 minutes.
  3. Do not eat dried or dried fish.
  4. Deworming of pets.
  5. Get regular checkups, even if you don't have any pathological signs. The most common diagnostic methods are macroscopic and microscopic examination of feces. The first method allows you to detect adults, the second - eggs and worm larvae.