Dwarf Tapeworm (hymenolepis Nana): Life Cycle, Symptoms And Treatment

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Dwarf Tapeworm (hymenolepis Nana): Life Cycle, Symptoms And Treatment
Dwarf Tapeworm (hymenolepis Nana): Life Cycle, Symptoms And Treatment
Video: Dwarf Tapeworm (hymenolepis Nana): Life Cycle, Symptoms And Treatment
Video: Hymenolepis nana (Dwarf Tapeworm): Parasitology simplified: Dr. Tanmay Mehta 2023, February

Page content

  • How does hymenolepiasis infection occur?
  • The structure of the dwarf tapeworm
  • Life cycle
  • Dwarf tapeworm symptoms
  • Diagnostics
  • Treatment for the parasite

    • Drug therapy
    • Therapy with folk remedies
  • Prevention
  • You can defeat parasites!

Dwarf tapeworm (hymenolepis nana) is characterized by increased parasitic activity in the body of its host. Most often, it attacks people and rodents. Once in the body, the tapeworm begins the process of migrating through the body. And what is equally important, this is accompanied by factors unfavorable for the carrier of the disease, one of which is the production of toxins.

All these processes can harm the body. The person may have problems with the functioning of the digestive system. This is expressed by mechanical damage to the intestinal walls by helminths, as well as intoxication of the body caused by the waste products of parasites.

What to do in such a situation? To get started, we recommend reading this article. This article details the methods of dealing with parasites. We also recommend contacting a specialist. Read the article >>>

Dwarf chains parasitize in the intestines. They also negatively affect the functioning of the organ, damaging its mucous membrane. As a result, such processes can lead to blood loss. Also, these helminths disrupt the metabolism, eating large amounts of vitamins and minerals in the body.

How does hymenolepiasis infection occur?

The dwarf tapeworm has several intermediate hosts and one main one, which is a person. The transmission of hymenolepiasis occurs by the fecal-oral route. The main causes of infection are the following factors:

  • eating contaminated food (the main reason is insufficient heat treatment);
  • non-compliance with the rules of personal hygiene;
  • keeping eggs or larvae on the surface of household items, as well as in ordinary dust or drinking water.
  • eating fruits and vegetables, with some insects (intermediate hosts of the parasite).

The structure of the dwarf tapeworm

Describing the structure of the dwarf tapeworm, parasitologists note that its morphology is no different from the structure of other representatives of the class of tapeworms - intestinal anaerobic parasites of vertebrates.

The structure of the dwarf tapeworm
The structure of the dwarf tapeworm

The body length of an adult, that is, a dwarf tapeworm ready for reproduction, does not exceed 40-50 mm, and its width is 1 mm. The body of the parasite is a strobila - a chain of two to three hundred repeating segments or segments (proglottids). Also in front of each worm there is a scolex (head) and a neck. The scolex of the dwarf tapeworm has four bothria, (slot-like sucker), and between them is a retractable rostellum (proboscis), along the entire upper edge "armed" with about three dozen hooks. Thanks to such "equipment" the tapeworm is easily fixed on the mucous membrane of the small intestine. Here, in the scolex, is the main nerve center (ganglion), from which the sensory and chemoreceptor nerve cords stretch along the entire strobila.

Immediately after the scolex is the worm neck, in the process of growth of which new proglottids are separated. That is, the maturing segments are gradually pushed aside by the younger ones to the end of the chain. Moreover, each segment eats independently and has its own hermaphroditic reproductive system, which works hard. And by the time a mature proglottid reaches the end of the worm's body, it has become a sack filled with eggs. Then the segment simply disconnects from the body of the worm and, having fulfilled its function, is destroyed, freeing the eggs.

The eggs of the dwarf tapeworm (0.03-0.05 mm in diameter) are covered with a thin hyaline membrane on the outside and have a thickened inner membrane. Each egg contains a larval embryo (oncosphere) with hooks up to 0.015-0.018 mm in diameter.

The dwarf tapeworm does not have a digestive system, and ready-made nutrients from the small intestine of the host are simply absorbed by the cells of the worm tegument - a multilayer surface tissue (7-15 microns thick), consisting of syncytium (multinucleated tissue), distal cytoplasm (having plasma membranes), glycocalyx (layer of carbohydrate-containing macromolecules) and the proximal cytoplasm (the inner layer, which contains the nucleus, endoplasmic reticulum, mitochondria, ribosomes, etc.).

The inner layer of the superficial tissue of the dwarf tapeworm strobila is limited by the basal plate, under which are muscle fibers that provide the body with the ability to move. Nature took into account the fact that the nutrition of this type of cestode occurs by endocytolysis, therefore, the release of metabolic products occurs through special cells - protonephridia.

By the way, it was found that complete dependence on the host, in whose intestines this parasite settles, is associated with its inability to synthesize lipids. Moreover, the dwarf tapeworm and other cyclophyllides need lipids not as a source of energy, but exclusively for strobilation - asexual reproduction.

The structure of the dwarf tapeworm
The structure of the dwarf tapeworm

Life cycle

In the majority of cases, the life cycle of a dwarf tapeworm, which lasts about 30-45 days, takes place in one organism.

The causative agent of hymenolepiasis enters the body of a healthy person in the form of eggs, which come out of the intestines of an infected person with feces. Outside the host's organism, eggs with oncospheres retain their viability for a short time, but this time is enough for some of them to be “attached” inside another host. The intermediate host of the dwarf tapeworm is a person in whose intestines the hymenolepis passes an intermediate stage of its development. And the person in whose intestines this worm multiplies is the definitive or final owner of the dwarf tapeworm.

In the human mouth (and then in the intestines), the eggs of the parasite can be found together with food on which flies have sat (mechanical carriers of any helminths), with contaminated water, from unwashed hands, from dishes, in general, from any objects. If the habitat of adult tapeworms is the upper parts of the small intestine, then the eggs may not enter the feces, and then constant self-infection occurs. So the ways of infection with dwarf tapeworm, in the first case, are fecal-oral, and in the second, autoinvasive. Children are especially often infected with hymenolepiasis.

In the intestines of the final host - under the action of digestive enzymes - the hyaline membrane of the cestode eggs dissolves, and the embryo of the larva is free. Then comes the invasive stage of the dwarf tapeworm, during which the oncosphere with its hooks clings to the mucous membrane of the small intestine (to the loose tissue at the base of the intestinal villi) and within a few days a dwarf tapeworm or cysticercoid is formed. For some time, the Finna matures before the appearance of a scolex buried in the body and a body with a tail appendage.

But when the intestinal stage begins, the cysticercoid loses its caudal appendage, straightens the scolex, leaves its "home" place and digs into new intestinal villi in order to receive more nutrients and develop further. Two weeks later, the mature segments of the strobila of the dwarf tapeworm are filled with eggs, and everything begins in a new circle.

Dwarf tapeworm life cycle
Dwarf tapeworm life cycle

Dwarf tapeworm symptoms

Symptoms of the dwarf tapeworm, more precisely, the symptoms of hymenolepiasis, are associated with the fact that both adult worms and their larvae with their suckers and hooks damage a large number of intestinal villi - outgrowths that cover the entire mucous membrane of the walls of the small intestine. This leads to ulceration and necrosis not only of the limb epithelium of the villi, but also damage to the deeper layers of the intestinal walls and intestinal capillary vessels. At the same time, general poor health, abdominal pain (sometimes intense), diarrhea or constipation, mucous-bloody particles in the feces are noted. As a result of violations of the intestinal microflora, the digestion process is also disrupted, which causes nausea, vomiting, heartburn and belching.

Moreover, due to the damage of the parasite to the lymphatic and blood capillaries inside the villi, the flow of proteins, lipids and carbohydrates necessary for the body into the bloodstream is disrupted. And the dwarf tapeworm in a child (in addition to nausea and pain in the abdominal cavity) often leads to dizziness, fainting, loss of appetite and body weight, anemia, decreased activity, and sleep problems.

Parasitic invasion also causes allergic reactions, since the human immune system (in the intestine these are lymphoid follicles and Peyer's patches) cannot but react to a foreign protein as an antigen. As a result, when infected with this helminth, skin rashes, inflammation of the conjunctiva, and an allergic rhinitis can be observed.

Take a parasite test

Symptoms Answer Muscle weakness Yes Not Eructation Yes Not Stomach ache Yes Not Headaches Yes Not Vomiting Yes Not Weight loss Yes Not Epileptic seizures Yes Not Pain in the legs, arms and back Yes Not Diarrhea Yes Not Decreased appetite, intestinal discomfort after eating Yes Not


After the specialist interviews the patient, he prescribes laboratory tests that confirm the infection that caused the tapeworm. The patient will need to donate a stool sample for microscopic examination, in which doctors look for parasite larvae. Most often, the patient is assigned a three-time study with an interval of 5 days. Such measures are due to the fact that the life cycle of the dwarf tapeworm is approximately 1 month, due to which the study allows you to determine the presence of eggs in the body with an accuracy of 90 to 100%.

To significantly increase the likelihood of detecting a helminth, experts prescribe the drug "Fenasal" and laxatives to the patient before testing. "Fenasal" affects the body of the worm and destroys its end segments, releasing a large number of eggs, which are much easier to detect during analysis. Due to this, the information content of the study increases by about 40%.

Given that the eggs of the dwarf tapeworm in the environment are destroyed rather quickly, samples for laboratory research should be delivered to the laboratory as soon as possible after defecation. After a few hours, it is quite problematic to detect the presence of helminth infection, but to examine dry feces is completely ineffectual.

Treatment for the parasite

Drug therapy

Treatment for dwarf tapeworm begins with drug therapy, which is carried out cyclically in two stages for 5-7 days. Such measures are due to the fact that medicines have an effect exclusively on mature worms and are completely harmless to the larvae. Before a course of treatment is prescribed to get rid of the dwarf tapeworm, all systems of the patient's body are prepared.

After the patient's body is prepared, a drug is prescribed that is capable of treating worms. The most commonly used remedy for dwarf tapeworm is called Fenasal. The drug acts on the parasite itself and destroys it, disrupting the metabolic processes inside the worm. The drug treatment regimen is determined by the doctor and has 2 models:

  1. 2 courses, which last 4 days. They take a week break between them. "Fenasal" is consumed 4 times a day every 2 hours, or once a day a few hours before meals for 2 days.
  2. 6 courses lasting 2 days. There is a break of 5 days between courses.

To treat the disease, Praziquantel is also used at any stage, which has an effect on the helminth and weakens it, due to which the dwarf tapeworm is separated from the intestinal wall and excreted from the body with feces. Prescribed to use the drug after a meal 1 time or several times every 5 hours. It is important to note that the drug is contraindicated for use by children under 4 years of age, pregnant and breastfeeding women.

Therapy with folk remedies

Treatment with folk remedies is used as an auxiliary measure in drug therapy. The most common remedy is a decoction of bitter wormwood, for the preparation of which you need to add a spoonful of wormwood to a glass of boiling water, then insist and drink 60 milliliters 3 times a day. They also use a tansy decoction, which is easy to prepare. You should pour a spoonful of tansy with a glass of boiling water, insist and drink before eating 3 times a day.


To avoid the disease caused by parasites, it is important to wash your hands thoroughly with soap and water after going to the toilet, while eating and before preparing food. It is not recommended to put your fingers in your nose and mouth, as the parasite can live on your hands for up to 4 hours. Before eating vegetables and fruits, you should rinse them well under running water. Care should also be taken in places where rat droppings may appear.

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