The human ascarid

Human roundworm is a parasite that affects people of any age, mainly children, with the localization of the pathological process in the intestine and corresponding symptoms. This parasite is a representative of Nematodes - a class of roundworms. It is necessary to know some features of the life cycle of this worm in order to predict complications and conduct effective treatment.

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Structural features of the human roundworm

All types of worms are divided into classes, which correspond to the features of their structure, digestion and life cycle. Ascaris is a heterosexual organism, which has differences in structure between males and females. These parasites have an elongated, rounded shape. The female is significant in size - about forty centimeters long, while the male is twice as small - twenty to twenty-five centimeters. The male also has a pointed area at the end of his body, which allows him to be identified.

The outer layer of the roundworm is made up of hypodermis - this is similar in structure to epithelial cells, of which there are a significant number - ten layers, which play a protective role and prevent damage to the individual itself and digestion by intestinal enzymes. Under the hypodermis is a layer of muscle fibers that allow the roundworm to move actively. Further under the muscle fibers is a cavity filled with liquid. This structure allows the worms to maintain a constant body shape and elasticity.

The parasite's digestive system is represented by the oral cavity, which is surrounded by lips. Next comes the pharynx, represented by several layers of muscles - this structure helps to move food by contracting transverse muscle fibers. After the pharynx, food enters the intestine, which looks like a closed bag - there, digestion of food and final absorption of nutrients occurs. The human roundworm lives in the small intestine and feeds on nutrients that come there in the form of food. Therefore, all food products that enter the human intestine are a substrate for the worm's nutrition. Most predominantly, worms prefer sweet foods.

The excretory system of the roundworm is represented by two lateral canals that run along the body and correspond to the length of the roundworm's body. Harmful undigested substances after the intestines enter the cavity filled with liquid, and then into these canals. Near the initial end of the roundworm's body, excretory openings open, which correspond to the excretory organs.

The nervous system of the human roundworm is represented by nerve tubes, which are located on the sides of the body, they have connecting elements. This is how the innervation of the sense organs and other internal organs occurs. The sensory organs are very poorly developed - they are represented by bristles, which are the organs of touch.

The species of human roundworm that causes ascariasis is Ascaris lumbricoides, and there may be differences only in the length of the individual between males and females.

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Life cycle of the human roundworm

Ascaris has a very long life cycle, the peculiarity of which is the change of location of the individual in the human body. The routes of infection with worms from the class Nematoda are the fecal-oral route. The human ascaris belongs to geohelminths, because one of its development cycles is in the ground. Thus, infection occurs during the ingestion of ascaris eggs. The routes of infection can be the following:

1. dirty hands – children are at greater risk because they constantly play in the sandbox and eggs can be retained under their fingernails;
2. dirty, unwashed vegetables and fruits – during ripening, eggs from the ground can fall onto vegetables and berries;
3. after animals that have roundworm eggs on their fur – they can be carriers;
4. with unboiled water, which contains ascaris eggs;
5. food is not cooked properly, which does not kill the eggs or larvae of the roundworm.

The life cycle of the human roundworm has its own characteristics. The development of the human roundworm occurs without a change of hosts, so the final host of the human roundworm is only a person. The eggs of the roundworm enter the small intestine of a person through the mouth. Then the parasite goes through the stages of development in the form of a young larva, an adult larva and an adult worm. After the egg enters the intestine, the young larva emerges there, which hooks into the intestinal wall. Thus, the young larva penetrates the wall into the veins and enters the bloodstream. There, the young larva feeds on blood serum and then on erythrocytes, which allows it to grow to a significant size. In this case, the young larva turns into an adult, which migrates with the blood flow through the portal vein system to the liver, and through the inferior vena cava system to the right sections of the heart and lungs. Oxygen is necessary for the roundworm to grow, so it is sensitive, migrating specifically to the lungs, which are filled with oxygen. The further cycle of the roundworm is such that with a strong cough, the young larva gets into the throat, from where it is re-infected, and the roundworm gets into the intestines again. The adult worm lives in the intestines and feeds on the products that get there. The total duration of the cycle of one individual from the moment of entry to exit is about one year, but due to the fact that roundworms reproduce all the time during migration, the duration of such life cycles can be years.

Reproduction of the human roundworm is very complex, because the parasites are of different sexes. At the same time, the males have a cloaca, into which ejaculation occurs. The female has a complex reproductive system, which is represented by a spermatheca, vagina, uterus, ovaries and oviducts. Fertilization occurs in the spermatheca, after the male attaches to the female with special clamps. The female secretes a huge number of eggs, which can be excreted with human feces, and some of them are simply preserved and activated under favorable conditions.

Diagnosis and differential diagnosis of human roundworm

Diagnosis of human roundworm should be aimed at timely detection of the parasite and the fastest possible treatment, since the roundworm has the ability to migrate, causing complications.

Diagnostics should begin with a thorough anamnesis. Ascaris, being in the human body for a long time, contributes to the development of symptoms of intoxication, as well as dyspeptic disorders. Therefore, this disease will be accompanied by complaints of poor appetite, rumbling in the stomach, weight loss, nausea in the morning. If it concerns children, then it is clear that the child is thin, small, pale. Characteristic signs of ascariasis, like any other helminthiasis, are grinding of teeth at night during sleep. If such symptoms are observed for at least the last few months, then you should think about helminthiasis.

Symptoms of intoxication are also observed, which are caused by the constant persistence of the parasite. Ascaris feeds on what is in the intestines, and at the same time, the products of the helminth's vital activity enter the intestinal cavity, which is absorbed and contributes to the development of intoxication.

For timely detection and accurate confirmation of the diagnosis of roundworm parasitism, it is necessary to identify the pathogen. The simplest diagnostic method is a coprological examination of feces and detection of helminth eggs in feces. However, there are some peculiarities of such an examination. Stool analysis should be done on an empty stomach. Helminth eggs may not be excreted constantly, therefore, for diagnostics, as a rule, three repeated tests are carried out. If eggs specific to roundworm are found in one of the tests, then the diagnosis can be confirmed. Considering that accurate detection of eggs in feces is not always possible, there is a need for additional methods. Light microscopy is used, in which feces are stained with a special luminescent paint and, if eggs are present, they glow under a microscope. It is also possible to determine the presence of eggs and antigenic material in feces using a polymerase chain reaction (the method is based on the identification of the specific genome of roundworms). After treatment, a repeated stool test is always carried out to determine its effectiveness.

To determine the extent of the changes, a blood test is also performed. A general blood test will reveal changes in the form of eosinophilia, and there may also be anemia caused by the parasite feeding on red blood cells.

If human roundworm larvae enter the liver and lungs during migration, then non-specific symptoms with impaired intrahepatic bile outflow may occur. In this case, an informative method for identifying the cause of this pathology is an ultrasound examination. Ultrasound reveals anechoic foci in the liver that have clear edges and a rounded shape. Such changes can also be determined in the lungs, which allows one to suspect the presence of roundworm larvae.

Many of the helminths can cause similar symptoms to those caused by roundworms, so differential diagnostics must be performed. First of all, it is necessary to differentiate between ascariasis and bovine tapeworm.

The beef tapeworm is a parasite that is a representative of the Flatworms. This worm reaches a length of four to ten meters and is armed with suckers.

A comparative description of the bovine tapeworm and the human roundworm is necessary because they have similar symptoms - this is an intoxication syndrome and dyspeptic disorders with loss of weight and appetite. But there are also differences. First of all, the bovine tapeworm is a biohelminth. Therefore, the bovine tapeworm, unlike the roundworm, has an intermediate host - cattle. Unlike the human roundworm, infection with the bovine tapeworm occurs when eating poorly cooked cattle meat, which contains the larva of this parasite. Therefore, in the anamnesis, when parasitizing the bovine tapeworm, there is data on eating cattle meat. Another feature of the tapeworm is that its life cycle in the human body is not characterized by migration, and when it enters the intestine, it simply lives in the lumen and grows to a significant size. In this case, intoxication and disruption of nutrient absorption also occur. To detect and identify the type of pathogen, it is necessary to detect eggs, which is specific evidence.

Although the principles of treatment for different types of helminthiasis are similar, there are differences, so it is necessary to accurately differentiate the pathogen.

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Treatment and prevention of human roundworm infestation

Treatment of any helminthic invasion should be carried out only in combination with other means that prepare the gastrointestinal tract for deworming. Therefore, it is necessary to start with a diet that cleanses the intestines. It is necessary to completely limit sweet, starchy foods for the duration of treatment. It is necessary to eat porridge and cooked vegetables that stimulate intestinal peristalsis. After this, it is advisable to undergo a course of laxative therapy. To do this, it is necessary to undergo a single course with the use of laxatives. It is better to take herbal preparations with a laxative effect. These include "Senadexin" - a laxative based on senna leaves - a plant with a laxative effect. After such a course of cleansing therapy, they proceed to the treatment of the helminthic invasion itself. Anthelmintic drugs are used.

1. Pyrantel is an antihelminthic drug that acts against human roundworm by depolarizing the membranes of the worms' muscle cells, which contributes to the death of mature forms of roundworms. The drug is available in tablet and suspension form. The dosage for children is 250 milligrams under six years of age, and 500 milligrams for those over six years of age. For adults, the recommended dose for treating roundworms is one gram, i.e. four tablets per dose. Side effects from the digestive system in the form of diarrhea, abdominal pain, nausea, as well as changes in nervous activity in the form of dizziness, drowsiness, increased excitability, paresthesia are possible.
2. Vormil is an antihelminthic drug, the main active ingredient of which is albendazole. The mechanism of action of the drug is to disrupt the metabolism of ascaris cells. The advantage of this drug is that albendazole acts on both the intestinal form, that is, on the adult, and on the larvae and eggs. The drug is available in the form of chewable tablets and suspension. The dosage of the drug is one tablet at a dose of 400 milligrams once a day, the course of treatment is three days. Possible side effects of the drug in the form of drowsiness, dizziness, decreased performance, as well as dyspeptic phenomena.

Prevention of infection with human roundworm can be specific and non-specific. Specific prevention is taking anthelmintic drugs that are active against roundworms for prophylactic purposes. To do this, it is necessary to take anthelmintic drugs twice a year; for children, half the doses of therapeutic drugs can be recommended. Any anthelmintic drugs can be used - mebendazole, albendazole, Pyrantel.

Non-specific prevention should be used by all people, especially children. Before eating, it is necessary to wash your hands, fruits and vegetables should also be washed before eating. As for water and food, it is better for children not to drink water raw, and food should be sufficiently cooked. For good digestion and reducing the possibility of ascaris invasion, proper nutrition is necessary, which increases local immunity and the anthelmintic capabilities of the intestine.

The human roundworm is a geohelminth that parasitizes the human body in the small intestine. The danger of this worm is that it affects the intestinal mucosa, which reduces the absorption and assimilation of nutrients - this leads to weight loss and symptoms of intoxication. Considering that roundworms are very difficult to treat, since there are many immature forms in the body, it is necessary to carry out prevention of helminth infection.