Reproductive organs of a female human roundworm. What are roundworms? Skin-muscle sac of human roundworm

Many parents are very worried about their children and want to understand: toxocara - what is it? Every person should know about this in order to learn how to maintain their health and the well-being of their child, and to prevent the disease.

Most often they can become infected:

1. Children preschool age who often play with soil, sand, dogs, cats, or put them in their mouths dirty hands, items, since 80% of domestic yard sandboxes are contaminated with Toxocara eggs.
2. Professionals who, on duty, work with animals, products, and soil. Dog handlers, sellers, veterinarians, drivers, utility workers, and dog breeders are at risk.
3. Owners of personal plots, land plots, dachas, vegetable gardens.
4. Lovers of hunting with dogs.

Put correct diagnosis with this disease it is not easy, since it is difficult to detect invasive worm larvae migrating in the body.

Toxocara carriers are stray cats and dogs. Immature larvae of helminths of these domestic animals, once in the human body, cause significant harm, which has devastating consequences. People with toxocariasis are not sources of infection for other people, since immature larvae in their bodies do not develop into mature nematodes.

If an infection occurs with this terrible disease, they are affected the most important organs person.

You need to apply for medical care and get treatment from a doctor. It is important to engage in ongoing prevention of this disease, avoiding the possibility of infection with Toxocara.

Life cycle of roundworms: from egg to mature helminth

When it enters the intestine, the roundworm larva sheds its egg membranes. This process is called molting. By secreting its own enzymes, the immature roundworm dissolves the egg shell and comes out at the right moment.

Intestinal stage

From the entry of an immature egg into the human body until the first laying of eggs, 75-100 days pass. Although experience shows that immature larvae appear in feces after two months.

Atypical cyclical life of roundworms

Types of trematodes, symptoms and treatment of infestation

These worms can reach a length of 2 millimeters to 1.5 meters. Worms can grow to large sizes in the bodies of livestock, fish, and humans. They are mostly leaf-shaped or round in shape. Schistosomes differ in their shape, which are characterized by an oval or elongated body.

The class of trematodes includes more than 7300 various types flukes, of which human body can affect about 40 species.

Based on their habitat, they are conventionally divided into 4 groups:

• affecting the liver;
• localized in the lungs;
• blood;
• leading their life activities in the small intestine.

All flukes have a similar development cycle.

Life cycle

The life cycle of trematodes is as follows:

Only 12 species of trematodes are dangerous to humans, as they are pathogenic agents varying degrees. Trematodes in humans are divided into 2 groups.

Schistosomes

Can affect the human body the following types schistosome:

• Mansoni;
• hematobium;
• Japanese;
• intercalatum.

Schistosoma Mansoni can be infected in the Middle East, the African continent, South America, and the Caribbean. Hematobium is common in Africa and the Middle East. The Japanese schistosome lives in China, East Asia, and the Philippines. Intercalatum is localized exclusively on the African continent.

Other trematodes

Paragonimus Westermani, a pulmonary fluke, is capable of spreading eggs along with human saliva.

Among the main flukes that are not related to schistosomes are:

• Fasciolopsis Buski, the source of which is plants contaminated with helminth eggs. This worm mainly spreads in Asia and India;
• heterophyosis - can be infected in Asia, Eastern Europe, the Middle East, and also in Egypt. The carriers are fish;
• Metagonimus Yokogawa - common in Siberia, its carriers are trout and carp;
• gastrodiscoidosis Hominus - can be contracted in India, Vietnam, and the Philippines through consumption of contaminated plants;

• development allergic reactions in the form of hives and itching sensations;
• development of dyskinesia bile ducts;
• appearance pain in the abdominal region;

• increased volume of the liver and spleen;
• regular occurrence of headaches and migraines;
• development of blood eosinophilia.

Typically, primary symptoms appear 3-4 months later - after incubation period. During this time, the helminth reaches a sexually mature state and begins to actively reproduce. It is worth considering that adult worms are capable of mechanical damage soft fabrics, and also internal organs.

In some cases, trematodes in the human body cause:

• blockage of the choleretic ducts;
• development of microabscesses;

• the appearance of micronecrosis of organs.

Pathology in advanced cases is accompanied by thickening of the walls of the bile ducts and adenomatous proliferation of epithelial tissue. Such processes can lead to angiocholitis and atopic cholecystitis.

Treatment

Treatment for fluke depends on its type. General principles therapy consists of:

• pathogenetic treatment;
• anthelmintic treatment;
• therapy that improves immunity.

Symptoms of intoxication are eliminated with the help of pathogenetic therapy. Also, as part of such measures, it is necessary to take antihistamines. If you were hit digestive system, then during this period a diet, hepatoprotectors, and choleretic medications are prescribed.

The most commonly used anthelmintic medications are:

• Praziquantel - for the treatment of schistosomiasis, clonorchiasis, paragonimiasis, opisthorchiasis;
• Triclabendazole, Albendazole – for the treatment of liver fluke, giant fluke;
• intestinal schistosomiasis is treated with Oxamniquine;
• genitourinary schistosomiasis – Metrifonate.

If a person develops symptoms of trematodosis, he should consult a doctor as soon as possible, and then begin the prescribed treatment. This is due to the fact that this pathology treated faster and more effectively at the initial stage.

Have you even read anything about medicines designed to defeat the infection? And this is not surprising, because worms are deadly to humans - they can reproduce very quickly and live for a long time, and the diseases they cause are difficult, with frequent relapses.

Bad mood, lack of appetite, insomnia, dysfunction immune system, intestinal dysbiosis and abdominal pain... Surely you know these symptoms firsthand.

Species

Routes of infection

By adhering to basic hygiene, you can reduce the risk of infection with worms.

They usually become infected when basic rules of personal hygiene are not followed. Invasion is also possible when drinking unboiled water from contaminated sources. Flies and other insects carry eggs on their legs. When they land on food or a table, they transmit helminth eggs. Often the carriers are domestic animals - cats, dogs. The route of transmission of roundworm eggs to humans is oral.

The structure of the roundworm's body

A female roundworm can lay more than 200 thousand eggs in just one day.

The reproductive organs are very well adapted for maximum reproduction of offspring. Helminths have a special type of relationship, thanks to which one individual reproduces once a day, laying several hundred thousand eggs. The female has 2 ovaries and 2 uteri, and the male is endowed with a long testis. Eggs laid by females are released along with feces and a new one begins. life cycle human roundworm. Reproduction of roundworms depends on the characteristics human body.

Development life cycle

Once in the intestine, the roundworm egg shell dissolves and the immature larval form of the worm enters the intestine. Then, by boring through the intestinal walls, the roundworm larva penetrates the blood and migrates along with the bloodstream. In the intestines, roundworm worms reach sexual maturity and begin producing eggs. Together with feces, the eggs are released into the external environment and the life cycle begins all over again.

Symptoms of ascariasis in humans

In most cases, ascariasis first causes a feeling chronic fatigue.

Blood test for antibodies When starting a diagnosis, it is necessary to take into account that it is much more difficult to detect larvae at the stage of migration. Differential analysis will be very important in such cases. After the research, the difference between ascariasis and other helminth infections will be obvious. Several types of research are carried out:

• hematological;
• immunological;
• X-ray.

The helminth Ascaris lumbricoides is one of the largest dioecious worms. An adult male can reach 25 cm in length, and the female is even larger - up to 40 cm. The body color ranges from pink to yellow-white. The male has a curved tail. Adult worms live in small intestine, feed on the contents of the intestine and its mucous membrane. IN intestinal tract Ascaris curls into a spiral and is held against the walls. Only dead individuals are removed with feces. The helminth goes through developmental stages, including the imago ( adult stage), larva and egg.

The life cycle of roundworm consists of several stages, including mandatory place its passage:

• Adult. Lives, feeds and reproduces in the human small intestine. A female can lay up to a quarter of a million eggs per day (some of them unfertilized). The eggs are released.
• Egg. Oval or round shape. Can't see it with the eye. Feces colors. The eggs develop in the soil. This requires certain conditions: high humidity, heat, oxygen. If the regime is followed, they are initiated. The egg becomes infectious after the larva formed in it molts. It takes 10-15 days to ripen.
• Larva. Microscopic in size, not visible to the eye. It exits the egg into the intestine, pierces the membrane and enters the intestinal veins. From there through the portal vein to the liver. Here she goes through her 1st molt. Through the veins in the liver, it migrates through the inferior vena cava into the right atrium. From there it migrates to the lungs, where it undergoes the 2nd moult. It reaches small vessels near the alveoli and enters their space. With the help of the bronchial epithelium, it is expelled into the pharynx. Then it is swallowed and again ends up in the intestines, where it undergoes the 3rd molt. Only after such a route is it able to turn into an adult. The migration period is about 2 weeks. Here, after 2 weeks, she undergoes another, 4th molt, and turns into an adult.

The full development cycle (until a new egg) takes about 3 months. The individual lives no more than 1 year.

During the migration period, some larvae can pass through the pulmonary artery, vein, left ventricle of the heart, then they enter big circle blood circulation and end up in any organ. There they are surrounded by a capsule and die.

Sometimes unusual movements of adult helminths are observed. They can exit the esophagus and go down the trachea, causing asphyxia.

Clinic

Clinical manifestations are varied. Ascariasis sometimes does not make itself felt; a person does not even suspect that he is infected. It can occur with symptoms of pneumonia, myocarditis, hepatitis, pancreatitis and inflammation of other organs.

In the intestinal (late) stage of the disease, symptoms are associated with the presence of adult roundworms in the small intestine. Complaints from the intestinal tract are observed:

• nausea and vomiting;
• gas formation;
• pain in the upper abdomen;
• unstable stool;
• weight loss.

On late stage The disease manifests other symptoms: sleep disturbance, nervousness, fatigue, weakness, convulsions.

Complications

The main danger is complications of ascariasis. People with poor health, young children and pregnant women are at particular risk. In a weakened body, roundworms multiply very actively. The most frequent complications are:

The following forms of this disease in humans are distinguished:

• Skin. Manifests itself in the form of allergic skin rashes with itching and swelling.
• Visceral. It appears after the penetration of a large number of larvae. It is expressed by the appearance of fever, dry night cough, shortness of breath, abdominal pain, nausea, vomiting, flatulence, diarrhea, and enlarged liver.
• Neurological. It is a consequence of the penetration of larvae into the brain. Distracted attention, hyperactivity, and difficulty reading are observed.
• Ocular. Usually one eye is affected. Strabismus, keratitis, neuritis are observed optic nerve, decreased vision.

Read about the treatment of roundworms medications and folk methods;

How do roundworms differ from flatworms?

Roundworms: characteristics

Worms, having penetrated the human body, settle in the intestines. In the external environment, they can be found on the fur of infected animals, on unwashed vegetables and fruits, as well as in meat.

Types of roundworms

Flatworms: characteristics

These worms have the following characteristics:

Flukes and tapeworms pose a danger to humans. The liver fluke, which affects and destroys the liver, causes harm to the body.

No less dangerous is the cat fluke, which causes the development of opistrochiasis. The pulmonary fluke settles in respiratory tract. You can become infected by eating crayfish and crab meat.

Comparing the characteristics of both classes, it becomes clear how they may differ flatworms from roundworms.

To avoid infection, it is necessary to observe the rules of personal hygiene, thoroughly wash vegetables and fruits, and thoroughly process and boil meat.

It is also important to have an idea about external structure helminths and what their differences are.

Have you even read anything about medicines designed to defeat the infection? And this is not surprising, because worms are deadly to humans - they can reproduce very quickly and live for a long time, and the diseases they cause are difficult, with frequent relapses.

Bad mood, lack of appetite, insomnia, immune system dysfunction, intestinal dysbiosis and abdominal pain... Surely you know these symptoms firsthand.

This type of animal combines spindle-shaped worms: their body is round in cross-section, pointed at both ends and is not divided into segments. Their length is usually a few millimeters, rarely reaching a meter. They all look alike. This is one of the types that have achieved the greatest success in the animal kingdom!

Roundworms are a group of worms that have an elongated, non-segmented body, round in cross section, a primary cavity filled with liquid (in which internal organs are located) and not associated with external environment. In their body they have a through intestinal tube that ends in the anus.

External structure

The body of roundworms is gradually narrowed towards the anterior and posterior ends, almost round in cross section, non-segmented. The outside of the body is covered with a cuticle; underneath it lies a layer of epithelial cells. Below are the muscles - four longitudinal single-layer ribbons. This structure allows roundworms crawl, bending the body. The cuticle, epithelial cells and muscles form the skin-muscle sac (body wall). Between it and the intestine is the primary body cavity. It is filled with liquid, which, due to pressure, maintains a constant body shape, promotes the distribution of nutrients throughout the animal’s body, and the movement of decay products to the excretory organs.

These animals were the first to learn to burrow into soil or other substrate rich in food, such as plant tissue. Thus, they found not only a new habitat with its food supplies, but also shelter from predators - large eyelash worms.

With such a life, the mouth of roundworms is located strictly at the front end of the body. Pressure inside the hydroskeleton makes it difficult to swallow food. Therefore, their muscular pharynx acts like a pump with valves: it sucks in food and then forcefully pushes it into the intestine.

The external similarity of roundworms is due to the fact that, despite their widespread distribution, they all live in a similar environment - in a nutrient substrate. In the bottom silt and soil, this “soup” is made up of the remains of organisms, along with bacteria and protozoa, and in plants and animals - the nutrients of their bodies. The main difficulty in these conditions is caustic chemicals. But the cuticle reliably protects from them. Some species can even survive in vinegar.

Internal structure of the body of a roundworm

Digestive system

The mouth opening is located at the anterior end of the body and is surrounded by lips. The anterior part of the intestine, the pharynx, has dense muscular walls. Free-living nematodes feed on bacteria, algae, and organic debris - detritus. Some have cuticle outgrowths in the throat - peculiar teeth. With their help, nematodes pierce the integument of animals and plants.

Body cavity

Previously, nutrients were distributed throughout the body by a branched intestine. Now that the intestine has turned into a straight tube, this function has been taken over by the body cavity - the fluid-filled space between the skin-muscular sac and the intestine.

The liquid is not cells; it would leak out if it were not packaged in an impenetrable elastic cover. This cover is formed by a layer of ectoderm cells and covered with cuticle - a durable film. The cuticle not only protects against mechanical damage and toxic substances, but also restrains the pressure of the cavity fluid.

As a result, the body cavity, surrounded by a cuticle and filled with liquid, acquires the elasticity of an inflated ball and forms a hydroskeleton. It is the hydroskeleton that gives roundworms their characteristic shape and serves as a support for muscles. Their muscles are only longitudinal. They are located inside the cavity, along the walls of the body. By contracting alternately the dorsal and abdominal muscles, the worm bends and moves forward, lying on one side.

Gas exchange and metabolism

Excretory system

The excretory system consists of two lateral blindly closed channels. They open outward with an excretory opening on the ventral side of the front of the body. The walls of the canals are formed by one or several very long cells (their length can reach 40 cm). Harmful substances formed in the body enter the cavity fluid, then into the channels of the excretory system and are eliminated.

Nervous system

The nervous system of nematodes is represented by longitudinal nerve trunks connected by annular bridges. Nerves extend from them to the muscles and sensory organs.

Sense organs

Reproduction

Nematodes are dioecious animals. The genital organs have the shape of tubes: in females they are paired, in males they are unpaired. Females have paired ovaries and oviducts, one uterus and a genital opening that opens on the ventral side of the body.

The male has one filamentous testis, gradually turning into a larger vas deferens. It flows into the hindgut just before the anus. The male has retractable cuticular needles, with the help of which he introduces sperm into the female’s genital opening.

Every day, one female human roundworm is capable of producing 200,000 eggs. The eggs are covered with a dense shell that protects them from the effects of adverse factors (drying, etc.). The crushing of the egg and the development of the larva lasts about a month and can only occur in a humid environment with a sufficient amount of oxygen.

Development cycle of the human roundworm

Human infection occurs when eggs containing larvae are ingested in contaminated water or food. Eggs can be found on poorly washed berries (especially strawberries) or vegetables from areas where human excrement is used to fertilize.

In the human intestine, the shell of eggs is destroyed, the emerging larvae drill through the intestinal wall, enter the bloodstream and reach the heart, and then through pulmonary artery- into the lungs. In the lungs, the larvae molt twice, invade the alveoli, move along the trachea into the pharynx, and from here, together with sputum and saliva, enter the intestines for the second time. Only after such migration the larvae reach small intestines sexually mature form. The entire development cycle occurs in one host.

Figure: Human roundworm (male below)

Skin-muscle sac of human roundworm

The body of the roundworm is dressed on the outside with thick multilayer shell, under which there is a layer of muscles fused with it. These muscles are only longitudinal, so the roundworm can bend its body, but is not able to extend or shorten it.

Body cavity of a human roundworm

Figure: dissected human roundworm

Under the skin-muscle sac there is a body cavity. It does not have its own walls, that is, it is simply a space filled with liquid in which the digestive and reproductive organs are located. The fluid in the body cavity is under pressure, so the body of the roundworm is dense, constantly maintaining its shape. In addition, this liquid serves as an intermediary in the distribution of nutrients and in the removal of unnecessary processed substances.

Digestive organs of the human roundworm.

At the front end of the roundworm's body there is a mouth surrounded by three lips. From the mouth, through a muscular pharynx, which sucks food, food passes into the intestines - a thin straight tube. Undigested leftovers food is removed through anal, or anus, located at the posterior end of the roundworm's body.

Reproduction and development of the human roundworm

Roundworms are dioecious. The female has two ovaries, the males have one testis in the form of long thin convoluted tubes. The roundworm is extremely prolific: the female lays hundreds of thousands (up to 200,000) eggs every day, covered with a very dense shell. Eggs from the human intestine fall into the soil, where sufficient moisture and air access contribute to their development. After 2-3 weeks, larvae develop inside the eggs.
Eggs with larvae, together with poorly washed vegetables or with insufficiently clean hands, can get into a person’s mouth, and from there into the intestines. Here the larvae emerge from the eggs and burrow into the intestinal walls, and from there they enter the blood vessels. Together with the blood flow, they are carried into the lungs. Here the larvae penetrate through the walls of the alveoli (pulmonary vesicles) into the bronchi, trachea and oral cavity. Then, with phlegm or saliva, they return to the intestines, where they grow into adult worms. This journey of larvae through the human body lasts 1-2 weeks.

Harm of human roundworm

Although roundworms do not feed on human blood or intestinal cells, they poison the body with toxic secretions, causing intestinal disorders and headaches. When larvae burrow through the walls of the lung, they can cause pulmonary diseases. The main control measures are prevention and compliance with hygiene rules. If you become ill, you should consult a doctor.