Hepatic Fluke: Structure, Developmental Cycle, Symptoms And Treatment

Table of contents:

Hepatic Fluke: Structure, Developmental Cycle, Symptoms And Treatment
Hepatic Fluke: Structure, Developmental Cycle, Symptoms And Treatment

Video: Hepatic Fluke: Structure, Developmental Cycle, Symptoms And Treatment

Отличия серверных жестких дисков от десктопных
Video: FASCIOLA HEPATICA || LIVER FLUKE || STRUCTURE || LIFE CYCLE || SYMPTOMS || TREATMENT || BY PHANINDRA 2023, February
Anonim

Throughout its life, the human body is a target not only for external pathological agents (viruses and bacteria), but also for internal infections, which for many years, being in the body, undermine its normal functioning. The causative agents of internal infections include parasites that cause various helminthiases. One of the most dangerous pathogens is the hepatic fluke. This helminth causes a chronic disease - fascioliasis, in which the normal functioning of the liver is disrupted and pathological changes in hepatocytes (cells of the liver parenchyma) develop.

Content

  1. What is a liver fluke
  2. Types of liver flukes
  3. Fasciola ordinary or liver fluke (Fasciola hepatica)
  4. Fasciola giant (Fasciola gigantica)
  5. Chinese liver fluke (Clonorchis sinensis)
  6. Development life cycle of the hepatic fluke
  7. How can you get the liver fluke?
  8. Signs of a liver fluke
  9. Diagnostics
  10. Fascioliasis treatment
  11. An overview of the best anthelmintics
  12. Hepatic fluke

What is a liver fluke

Hepatic flukes are flatworms from the class of trematodes (digenetic flukes) that parasitize the liver and bile ducts of humans and animals.

Image
Image

All flukes are divided into three subclasses:

  • monogenetic flukes (Monogenea);
  • digenetic flukes (Digenea);
  • aspidogastrea (Aspidogastrea).

The first class of flukes parasitize cold-blooded animals: fish, amphibians and reptiles. Aspidogastreis parasitize in the body of mollusks, and the form of parasitism can be both external and internal. Helminths of these two species do not need intermediate hosts.

Digenetic flukes have a very complex life cycle and require at least one intermediate host change. Mature individuals lay a huge number of eggs that end up in freshwater bodies. In water, they are swallowed by intermediate hosts. As a rule, crustaceans or freshwater snails serve as intermediate hosts. In their body, the parasite develops to the stage of miracidia (larvae). During this period, the larva of the liver fluke is already invasive (infectious) and is capable of infecting the final host when it enters its body. The final owner of the liver fluke is a person or any warm-blooded animal.

The reproductive organs of the parasite are well developed, but since the hepatic fluke is a hermaphrodite, for its fertilization it secretes both male and female sex cells.

However, the parasite does not have an anus, and all toxic waste products are excreted through its oral cavity.

Types of liver flukes

In humans, several types of hepatic flukes parasitize:

  • common fasciola (Fasciola hepatica);
  • fasciola giant (Fasciola gigantica);
  • Chinese liver fluke (Clonorchis sinensis).

Fasciola ordinary or liver fluke (Fasciola hepatica)

Fasciola ordinary or hepatic fluke reaches a length of 2-3 cm and has a leaf-shaped body. This type of fluke is the causative agent of a helminth infection called fascioliasis. This is a rather formidable disease, expressed by hepatic colic and cholecystitis. Not yet ripe eggs of the hepatic fluke come from the liver to the intestines, and from the intestines together with feces into the environment. For subsequent ripening, the eggs must definitely get into the water. In water, they penetrate the body of an intermediate host (in this case, a freshwater snail). There, the parasite undergoes some metamorphosis and, as a result, a cercaria larva is formed. After the larva has completed the development cycle in the snail's body, it leaves it and swims freely in the water for some time.It then takes the form of a cyst and attaches itself to the surface film of water or aquatic vegetation. In such a favorable environment, it retains its viability for a long time.

Image
Image

The encystised larva enters the human body when drinking water from an infectious reservoir, or when eating vegetables and greens containing fluke larvae. In the intestine of the main host, under the action of certain enzymes, the egg membrane dissolves, releasing the immature worm. The parasite migrates through the intestinal wall, localizing forever in the liver, where it fully matures into a sexually mature individual.

Fasciola giant (Fasciola gigantica)

The length of the giant fasciola reaches 7 cm, and the shape of the body is lingual. The internal structure of these species is almost identical. They have two suction apparatus: abdominal and oral. In some species, there is also a third sucker, which is located at the posterior end of the body. With the help of these suction cups, helminths are fixed on the intestinal walls. Since the hepatic fluke is always localized in a certain place, it does not have a locomotor apparatus. The fluke feeds on blood and tissue juice, which it sucks from liver cells. Fluke eggs are large, with a brown or yellow shell. From their eggs, a larva hatch, attaching itself to an intermediate or final animal, in which a certain cycle of its development must go through.

The excretory and nervous system of the fluke is primitive, like many parasites. She has neither the senses nor the circulatory system. The upper shell of the fluke body protects it from the aggressive effects of enzymes and bile.

Chinese liver fluke (Clonorchis sinensis)

This type of fluke is the causative agent of helminthiasis called clonorchiasis. It is distributed in the East mainly in China, Korea and Japan. An adult worm is 10 to 25 cm long. The life cycle of this species is similar to the liver fluke, but it needs two intermediate hosts. The first intermediate host of the Chinese fluke is a freshwater snail, but of a different species, in contrast to the liver fluke. The second intermediate host is freshwater fish. Upon penetration into the body of the fish, the transformation of cercariae into metacercaria occurs. Man and other animals become infected with this helminth when eating fish that has undergone poor-quality heat treatment.

Image
Image

Development life cycle of the hepatic fluke

The life cycle of the parasite has the following developmental stages:

  1. A new development cycle begins when the fertilized egg is excreted from the body of the main host along with the feces. Further, the egg must necessarily fall into a freshwater reservoir or be on the shore of such a reservoir. After about two weeks, a larva is released from the eggs, which is called miracidia. During this period of development, the larva swims freely in the reservoir, not yet needing nutrients for its growth and development. Thus, it moves through the reservoir in search of a potential intermediate host. They become molluscs or freshwater snails.
  2. Once in the body of a freshwater mollusk, the larva secretes a pungent secret that breaks down the tissues of the mollusk and penetrates into its body. During this period, miracidia turns into a sporocyst, and in it there are two types of cells - embryos:
  3. redia, which penetrate from the sporocyst into the liver of the mollusk and reproduce there, the unique ability of redia is that they are able to reproduce without fertilization, turning into cercariae;
  4. cercariae are the larvae of adult parasites that leave the body of the mollusk and swim in water, attaching to grass, aquatic plants, penetrating into the soil, encapsulating for a comfortable expectation of favorable conditions.
  5. Also, miracidia can continue their development in the body of freshwater fish as a second intermediate host.
  6. Cercaria enters the human or animal body by the oral route (if swallowed). In the intestine, its protective membrane is destroyed, and then its penetration into the liver. Within six months, the helminth develops to an adult, which reproduces and lays eggs. Fluke eggs along with feces are released into the environment, and the parasite's development cycle begins anew.

How can you get the liver fluke?

Many readers are interested in the question, how can a person become infected with a hepatic fluke? It is not at all difficult to become infected with this parasite. The following routes of infection exist:

Image
Image
  1. Orally (if swallowed). In this case, the fluke larvae enter the human intestine, and from there they enter the liver.
  2. When drinking water from unknown bodies of water.
  3. You can become infected by watering farm animals from sources and reservoirs. The hepatic fluke enters the animal's body and is localized in the liver, then the animal's liver gets to the person on the table and the person is already infected.
  4. When swimming in ponds, lakes, as well as in any other bodies of stagnant water.
  5. Using contaminated water to wash vegetables, herbs and fruits.
  6. Infection often occurs as a result of poor personal hygiene, especially while outdoors.
  7. Eating animal liver that has not undergone high-quality heat treatment.
  8. Often cats become the source of infection, because they are carriers of the cat fluke.

Signs of a liver fluke

The symptoms of fascioliasis depend on the stage of the disease. There are two stages of this disease:

  • migration (acute early);
  • chronic (late).

The migratory stage is the period during which the larvae migrate through the body. It lasts 4-6 weeks. The acute period of this stage is the penetration of the larvae through the fibrous membrane from the intestine into the liver. Sometimes the maturation of larvae occurs in places atypical for these helminths: the pancreas, subcutaneous tissues, and the brain. Penetrating from these organs into the liver, the larvae damage their integrity, which is fraught with serious consequences.

Image
Image

The main symptoms of the acute stage are:

  • severe allergies;
  • fever;
  • joint and muscle pain;
  • stool disorder: constipation or diarrhea;
  • enlarged liver;
  • nausea and vomiting;
  • breathing disorders;
  • damage to the respiratory system;
  • pain in the liver;
  • headaches;
  • asthenia;
  • loss of appetite;
  • insomnia;
  • erosion on the intestinal walls.

The migration stage lasts 1–2 months. If adequate treatment is not carried out, then the parasites continue their destructive effect in the body, and the disease becomes chronic.

The chronic stage of the disease is manifested by the following symptoms:

  • pain in the liver;
  • loss of appetite;
  • heartburn;
  • weight loss;
  • upset stool;
  • flatulence;
  • asthenia;
  • headaches and dizziness;
  • hepatitis;
  • cholecystitis.

Disorders from the nervous system are also observed:

  • hand tremor;
  • irritability;
  • nervousness;
  • aggressiveness;
  • depression.

Waste products released by parasites, entering the bloodstream, cause severe intoxication and allergization of the body.

With an advanced form of fascioliasis, conditions are possible that threaten with serious complications and even death.

Image
Image

With the development of this form, the following complications are possible:

  • bile peritonitis;
  • obstruction of the biliary tract;
  • oncological diseases of the liver, pancreas, gallbladder;
  • abscesses;
  • lesions of the nervous, cardiovascular, endocrine systems.

Infection with the hepatic fluke is especially dangerous during pregnancy. Helminth is able to penetrate the placenta and populate the organs of the fetus, which further provokes disturbances in the physical and mental development of the child.

Diagnostics

To diagnose the hepatic fluke, the following research methods are used:

  • general blood analysis;
  • stool analysis;
  • analysis of the duodenal contents of the liver;
  • ultrasound examination (ultrasound).

A general blood test will help to identify the acute stage of the disease, since during this period there is an increase in the number of leukocytes in the blood, and in the chronic stage of fascioliasis, their level is normalized.

Image
Image

Stool analysis is informative 3-4 months after infection, when adults begin to lay eggs. The disease is diagnosed when parasite eggs are found in the feces.

Analysis of the duodenal liver juice is able to show the presence of fluke eggs in the duodenal juice. This study is also carried out 3-4 months after infection.

Ultrasound of internal organs allows you to identify flukes in different organs of the abdominal cavity.

With positive test results, it is important to begin adequate treatment as soon as possible. To do this, you should visit a doctor - parasitologist.

Fascioliasis treatment

As a rule, the treatment of this parasitosis is carried out in a hospital. Anthelmintic treatment includes 3 stages:

  1. The first stage is preparatory. During this period, symptoms of general intoxication are removed, liver function is normalized, stagnation in the bile ducts is eliminated. For this, patients are prescribed sorbents, choleretic drugs and hepatoprotectors. Preparatory therapy lasts one week.
  2. The second stage is directly anthelmintic therapy. For the destruction of parasites, pharmacological antihelminthic drugs of a wide spectrum of action are used. Anthelmintic drugs are highly toxic, so they cannot be taken without a doctor's prescription. Such drugs are taken in a certain dose and with a strictly established scheme.
  3. The recovery stage is necessary to eliminate the consequences caused by the destructive action of helminths. In this regard, the intake of enzymes, sorbents, choleretic drugs, hepatoprotectors, vitamin and mineral complexes is provided.
Image
Image

Throughout the course of treatment, you must adhere to a certain diet - "Table number 5". Diet "Table 5" refers to the category of therapeutic, sparing diets, for diseases of the liver and dyskinesia of the biliary tract (impaired motility of the gallbladder and its ducts). The diet provides for the rational use of carbohydrates and proteins, with some restrictions on fats. The following foods are excluded from the diet:

  • containing purines (organ meats, fatty fish and seafood, and yeast);
  • containing extractives;
  • foods containing essential oils (garlic, onions);
  • foods containing cholesterol;
  • oxalic acid;
  • fats oxidized during frying.

The use of the following foods rich in fiber, pectins and lipotropic substances is encouraged:

  • vegetables and herbs;
  • fruits (especially apples, rich in pectins);
  • berries:
  • cereals;
  • lean meat and fish;
  • low-fat cottage cheese;
  • soy products;
  • egg white.

They also follow the plentiful drinking regime. All dishes from the above products are boiled or baked, in rare cases they are stewed. Food is consumed only warm or slightly hot.

An overview of the best anthelmintics

Since anthelmintic drugs have a high degree of toxicity, it is strictly forbidden to prescribe a medicine to yourself and self-medicate. For the treatment of fascioliasis, the following antihelminthic drugs are taken:

Image
Image
  • Triclabendazole. A broad-spectrum drug, the active ingredient triclabendazole reliably destroys tapeworms and flukes at any stage of development. The recommended dose is 10mg per 1 body weight. The tablets are taken twice a day at intervals of 12 hours. It is prescribed for children from 6 years of age. The price category is quite high.
  • Praziquantel. The drug is intended for the destruction of trematodes. It is taken three times 1 time per day. Sometimes a two-day reception is possible. The permissible dose is 0.25 mg per 1 kg of body weight. Contraindicated in children under 4 years of age.
  • Biltricide. The active substance is praziquantel. The drug effectively destroys hepatic flukes. The course of treatment 3 times a day for 1-3 days, depending on the intensity of the helminthic invasion. Assign 25 mg per 1 kg of body weight.

In the past, the drug Chloxil was used quite actively. It is currently out of production, but it is still found in some pharmacies. The drug is taken according to the scheme: the medicine dissolved in milk is taken 1 time a day, one hour after a meal, for 2 days. The drug is highly toxic, which contributes to the development of serious side effects.

Contraindications to the use of anthelmintic drugs are:

  • renal and hepatic impairment;
  • hypersensitivity to the substances that make up the drug;
  • pregnancy and lactation.

After taking the drug, the following side effects may occur:

  • dizziness;
  • weakness;
  • an allergic rash in the form of urticaria;
  • diarrhea;
  • nausea and vomiting;
  • decreased concentration of attention.

Hepatic fluke

To prevent the disease, it is recommended to follow the basic preventive measures:

  • thoroughly wash vegetables, herbs and fruits under running water, do not forget to pour boiling water over them;
  • disinfect or boil water before drinking;
  • buy meat and fish from reliable suppliers;
  • subject meat and fish to high-quality heat treatment;
  • do not eat raw fish, be careful with oriental dishes (sushi);
  • carefully use dried, smoked and dried fish;
  • deworming pets.
Image
Image

It should be remembered that in its advanced form fascioliasis is a threat to human life. After the course of treatment, it is necessary to undergo a re-examination to exclude reinfection (re-infection).

Popular by topic