Worms of enormous size, which affect only the human body. They grow in us, develop, passing through a number of specific stages. In doing so, they absorb the nutrients of our body, destroying our blood. This disease, about which many of us have heard, but did not betray this information of particular importance. After all, this is one of the most common helminthic invasions affecting a person, whose name is ascariasis.

Ascariasis: General Information

This type of nematode is not capable of partogenesis. Reproduction occurs only when sexually mature individuals of both sexes are present in the body of the carrier. Manifestations of ascariasis, which infected people most often complain about, occur at the stage of migration of mature individuals and their larvae in the host organism.

Most often, these manifestations are associated with impaired normal functioning of the gastrointestinal tract. The life expectancy of roundworm is 1-2 years. The death of an individual occurs as a result of natural gerontological changes.

An adult female is able to lay up to 200,000 eggs, up to 0.05-0.07 mm in size, having a round or oval shape during the reproductive period. At first, masonry lacks the ability to invade. It appears only after a certain period (usually about 10-14 days), provided that the eggs, all this time, will be in a favorable environment, which for them is wet soil with a temperature of about 25 degrees Celsius, where they fall after the act of defecation .

Below are the stages of the process that the embryo undergoes before it turns into a larva:

1. Morula.
2. Gastrula.
3. Tadpole.

Important! For the normal development of ascaris eggs, soil moisture should be at least 6-8%. Another important condition is a constant flow of oxygen, in the absence of which the development phase does not occur, but the viability of the egg is maintained.

The classic scheme of the life cycle ascaris

Only two weeks later, after being in a moist and warm earth, roundworm eggs turn into larvae, which, once ingested by the next carrier along with contaminated food or water, can already cause invasion. For the need for preliminary development of eggs to the larvae stage, which can occur only in the soil cover, roundworms received an alternative name: geohelminths.

Life cycle human roundworm   is divided into two main stages:

1. Stage of migration.
2. Intestinal stage.

The main places of their localization is consistently the liver, heart and lungs.

Oxygen is needed by the larvae to complete the maturation stage. Unlike adults, this gas cannot harm them. In the alveolar cells of the lung tissue, the molting process is completely completed, and the final transformation of the larva into young ascaris occurs, which, with sputum that coughs off, enters oral cavity   carrier and returns to the gastrointestinal tract, by swallowing mucus, which makes, subjected to invasion, man.

The key point characterizing this period is the final transformation of the larvae and young ascarids into an adult. During the intestinal stage, the worms grow to their maximum size.

For males, these figures are about 25 cm, for females about 40 cm in length. At the same time, their width reaches 3 and 5 mm, respectively. Further, for 1.5-2 years, roundworms continue their life cyclemating and constantly laying eggs inside the intestinal space. The whole process, from getting the Ascaris larvae into the human body and ending with the first clutch of sexually mature individuals, takes an average of 80-100 days.

In most cases, this is due to the ingestion of food contaminated with the larvae and drinking water that has not undergone proper sanitation!

Harm of ascarid invasion

The risk of complications increases many times with repeated invasions. In this case, the development of roundworm again goes through its entire cycle, during which the larvae fall into various organs and systems of the human body. Most of the complications are caused by the enhanced migration of ascaris larvae, as well as the excessive motor activity of adults, which some drugs may trigger.

The development cycle, which is characteristic of human roundworm, in some cases may differ from its classical course. The migration phase is not always replaced by the intestinal phase. A large percentage of the larvae migrating through the body of the carrier may linger in the tissues of the liver, and will be destroyed there by its protective cells.

The adult human ascaris has a length: the female is twenty to forty centimeters, the male is fifteen to twenty five. Reproduction in these helminths is only sexual. Breeding organs look like tubules. Fertilization is internal. At the time of fertilization, females and males are woven into a ball, which can seriously harm the body and cause an obstruction in the intestine.

The female roundworm lays daily more than two hundred thousand eggs, which are displayed with feces. Eggs are so well protected that they can not kill substances from the outside world, except for direct sunlight. And embryos are protected even from them. This type of worms was also named geohelminths, since one of the stages of the human roundworm cycle occurs in the soil. They are resistant to temperature effects, eggs can lie in the ground for more than twelve years.

Sources of infection

The main source of infection with ascariasis is the soil. You can become infected through dirty hands, unwashed or insufficiently boiled vegetables, unwashed berries and fruits. Flies from street needles also tolerate ascariasis. From person to person, the disease is not transmitted. Some more sources:

1. Water that has a connection with the discharge of sewage. Therefore you should not drink water coming from the tap.
2. Infected with ascariasis, above all, kids who take everything in their mouths. You need to watch out for children, especially in nature.
3. There are cases when ascaris eggs ripen in the human body itself.

The development cycle of human roundworm

  As mentioned above, eggs are excreted with human feces. They can be preserved in an anabiotic state for more than twelve years. It is difficult to chemically affect the eggs, however, they are completely destroyed when the temperature rises to 100 degrees, in other words, by boiling.

In order for the development of human ascaris to continue, the egg must become infectious, that is, the germ must begin to develop in it. Stimulates this process oxygen. Therefore, the egg must fall into the environment. If conditions are favorable, it begins to grow. At temperatures above twenty degrees an egg develops in two weeks. But this process can stretch over several months, or even years. Eggs can die only in arid climates, for example, if they are in sand or dry soil. Frost they are not afraid.

Inside the matured roundworm egg there is a fully formed larva, a reduced copy of an adult helminth. Life cycle, it begins, breaking through the shell and getting into the intestine. Next, the larva goes a long way until it is completely formed. The process scheme is approximately as follows:

1. The larva first penetrates the intestinal mucosa, then, with the help of a sharp end, into the blood vessels.
2. In Vienna she gets into the liver, then into the heart, then into the lungs.
3. In the form of sputum, the larvae are harvested by humans. And since we often swallow up phlegm, they again enter the intestines. Having gone through this whole cycle of ascaris, the human becomes an individual capable of reproduction.

The total cycle time is approximately two weeks. Migration of larvae is a mandatory point of maturation. After about two months, new helminth eggs begin to appear in the feces and can be detected using analyzes. The migration period has a number of dangers, both for roundworm and for man. Helminths can die from bile in the liver, can be spit out with sputum, however, they can also get stuck in the arteries and the heart. This can cause negative consequences for a person, sometimes even death.

Diagnosis of Ascariasis

  It is rather difficult to identify ascaris because of a multi-stage migration cycle. A specialist needs approximately two weeks to accurately understand whether worms are left in the body or not. The analytical base for the determination of these helminths is quite extensive.

  ➡ Classical feces analysis for the presence of helminth eggs.   As is known, females secrete a huge number of eggs, which are easily detected under a microscope. Eggs are elliptical, about fifty to seventy micrometers in size.

  ➡ Blood test.   The migration period of the larvae is associated with close contact with immune system. In the course of movement along the pulmonary artery, immunity creates special anti-ascaric leukocytes, which can be determined by blood analysis.

  ➡ Sputum analysis. Informative, of course, only at the lung stage of the disease.

  ➡ Urine analysis.   Ascaris vital products are volatile fatty acids. An increase in their coefficient in the urine may indicate the presence of helminth in the body.

  ➡ X-ray.    Applied to detect characteristic changes in the intestines and lungs, as well as to exclude pneumonia and intestinal obstruction.

  😳 In adults:

In the late stage of the disease, people experience discomfort in the small intestine. Ascariasis can be determined by the following symptoms:

• vomiting and nausea;
• reluctance to eat;
• bloating and flatulence;
• upset stool (diarrhea gives way to constipation);
• abdominal pain (usually near the navel);
• body weight decreases.

Often, frequent headaches, increased tiredness, insomnia, dizziness are added to the symptoms. Sleep becomes either very restless or absent altogether. Very rarely does the fear of the light develop.

  😳 In children:

  Scientists have discovered an interesting feature that babies do not suffer from ascariasis. This is due to special immune substances   from mother's milk, which impede the development of larvae.

At risk are children aged three to ten years. This is due to their age characteristics (they actively explore the world and often taste). Immunity to ascariasis in children of this age is absent, as well as formed hygienic skills.

In children, symptoms are stronger than in adults at the stage of migration. Children at this time begin to develop pneumonia, their temperature rises sharply and decreases.

The rest of the symptomatic course of the disease in children is similar to the symptoms in adults.

Treatment of ascariasis

Read more about the medical and drug treatment process. folk remedies   read articles: "" and ""

On the globe, there are organisms with a wide variety of development cycles. In mammals, to which a person belongs, this is the intrauterine development from the fertilized egg to the birth of a baby. In birds - laying and hatching eggs. But there are much more exotic options. One example is the development cycle of human roundworm.

In case of ascariasis, the presence and vital activity of helminths causes serious damage to human health. Ascaris pursue humanity from ancient times, in all countries and climatic zones ranging from the driest deserts to the permafrost regions.

In this article, we will consider the life cycle of human ascaris, which is without intermediate carriers, since adults live exclusively inside the human body. The structure of these worms. And the ways in which they infect a person.

Structure and features

Knowing the enemy, as they say "in the face," you can fight and win much more effectively with him. Therefore, we will first briefly examine other nuances, and then the life cycle diagram of these worms will be considered.

There are three stages in the life cycle of the roundworm:

1. The stage of the egg.
2. Larva.
3. Mature individual.

Roundworms are bisexual helminths, that is, there are both female and male individuals. Females are larger, can be 25–40 cm in length, and 4–6 mm in width. Males are smaller, 15–25 cm long, and 2–4 mm wide. External differences between males and females are not limited by size. The shape of the tail of the males has the form of a hook hook, and in females it looks like a cone.

The reproductive system of male Ascaris includes:

• testes - sex glands;
• sperm and ejaculatory channels;
• a pair of sticks, reaching a length of 1.5–2 mm.

Females have:

• two ovaries;
• two womb;
• one vagina.

The development cycle requires extraordinary fertility from it. Thus, an adult female can have 25-27 million eggs in her body. different stages   ripening, and postpone every day to 250 thousand pieces.

The body of a live worm has a spindle shape and a pinkish tint. Dead individual becomes whitish-yellow. Mature roundworm easily die from an excess of oxygen, if they leave the intestine in an open environment.

The digestive system in both sexes is identical and extremely simple:

• oral cavity;
• long cylindrical esophagus;
• intestinal tube;
• anus.

Fertilized eggs can be either oval or spherical, with a diameter of 40 to 70 microns. Ascaris eggs consist of a germ cell surrounded by a multi-layered protective membrane - a protein membrane with a rough, hilly structure. The eggs in the female body are transparent, and once in the human intestine during deposition, they darken, acquiring a brown tint. Sometimes ascaris eggs lack an outer shell. This makes them similar to plant cells and makes it very difficult to identify.

Larvae develop from germ cells inside the eggs. Being under a protective sheath, they look like a coiled worm. Having hatched from an egg, they unfold in length up to 0.2 millimeter with a hooked process.

Egg Development Stage

We begin to consider the development of human roundworm from the stage of eggs.

The eggs laid by the female in the intestine of the carrier, along with the feces, are eliminated from the body. The female lays eggs even in the absence of a male, but without fertilization, they will not be able to develop, and, therefore, will be non-infectious.

Fertilized eggs must somehow get into the soil, where the following conditions must exist for their further maturation:

1. The ideal soil types for ascaris are clayey or silty. Sandy or sandy soils are less suitable due to the more intense warming up by the sun, and the rapid loss of moisture.
2. The ambient temperature should be in the range of 12 to 36 ° C, the ideal value is 24 ° C. At lower temperatures, the development of eggs stops, and they die only if they cool below -20 ° C, and then only if it is cold. will last 20 days. In heat from 36 to 50 ° C, eggs cannot develop, but they do not lose their viability. Above 50 ° can withstand several days. At 100 ° C die instantly.
3. The life cycle of roundworm requires that the soil moisture content be at least 6–8%.
4. Unlike adults, eggs cannot live and develop with a lack of oxygen. But even his complete absence does not kill them completely, but only suspends the process of vital activity.

If all conditions are perfect, then in 12–14 days the embryo in the egg will fully develop, passing through the stages of morula, gastrula and tadpole, to the larva. In the worst, but acceptable conditions, this process stretches from a month to a year. When one or several factors become unfavorable, but not fatal, the development of the larvae stops. In such a state of waiting eggs can be up to 10 years. And as soon as the environmental conditions allow, they will continue their development.

The larva in the egg will wait until one way or another, does not fall into the oral cavity and esophagus of the future owner. Such an expectation can last up to 15 years, if a strong heat or frost does not kill the worm larva. And then human ascaris will move to the next life stage.

Stage of the larvae

After people swallow roundworm larvae in eggs, these embryos of future worms end up in the intestines, where molting takes place - release from under the shell.

Intestinal stage

Adults male and female worms mate. The female lays fertilized eggs. Hundreds of thousands of them leave the human body during bowel movements. And the whole cycle begins anew.

The bodies of dead Ascaris are also excreted from the intestine along with feces.

What will be the period from human ingestion of eggs with larvae, to the first laying of an adult female roundworm depends on various factors. On average, it takes three months, but more transient cases are recorded - less than 60 days.

Special studies were conducted to find out how much roundworm lives in the body of an infected person. It turned out that the period of active existence and reproduction of an adult individual can be 24 months. But the patient with ascariasis is under constant threat of self-infection. And then, the duration of the disease stretches for years.

Ways of infection

The presence in the life cycle of a roundworm of the stage at which eggs develop in the soil determines the most probable ways of human infection with these worms:

To minimize the risk of infection, you must carefully follow the rules of hand hygiene. Always wash any fruits, vegetables and greens. Use for drinking and in everyday life only purified water.

The development of roundworm is different in that it begins and ends in the human body, without a change of owners. How many roundworms live depends on how favorable their living conditions are. The worm lives from 10 to 24 months, after which it, partially decomposed, goes with feces.

In order to continue the existence of roundworm, the female throws the eggs fertilized and protected by the shells through the egg ejector into the human intestine. At this point, the embryo is non-invasive, that is non-infectious. For the formation of larvae requires the presence of oxygen, which is not in the intestine. Together with the feces, eggs are released into the environment. A further stage of ascaris takes place in the soil.

If only a female lives in the body at that time, then it releases unfertilized eggs of an elongated pear shape, filled with yolk cells from the inside and covered with a coarse protein shell from above. When diagnosing the detection of such eggs is very important, as it allows to establish the presence of invasion.

After exiting the intestine, the helminth embryos enter the soil, where they pass incubation period, that is, they do not develop for some time until the onset of optimal conditions. The maturation of the larva begins at an ambient temperature of +16 to +37 ° C and soil moisture of 8%.

The egg goes through several stages of embryogenesis: the blastomere is converted into a morula, then into a gastrula. After some time, a tadpole develops from an ellipsoidal embryo. After about 10 days, the egg is already mature larva, capable of independent existence. In order for the embryo to reach the state of invasion, it needs to be in the soil from 2 weeks to a month.

The next stage is the transfer of the egg into the human body. The main mechanism of infection is fecal-oral:

Tearing the lung tissue with the help of a special enzyme from the hyaluronidase class, the helminth is inserted inside the alveoli. Actively feeding and increasing in size up to 2-3 mm, ascaris passes 2 stages of molting.

During palpation of the abdomen in patients, it is possible to localize an elastic, round-shaped formation. In some cases, there is a rupture of the intestinal wall with the release of contents and worms in abdominal cavity, which leads to diffuse peritonitis and the development of sepsis.

Atypical cycle

Not always ascaris goes through a full development cycle. Often most of the larvae die in the liver under the influence of protective cells, and then decomposes in it, causing symptoms of intoxication.

Roundworm can penetrate the bile ducts and gallbladdercausing severe pain, fever and jaundice symptoms. Against the background of such a state, a person often has vomiting attacks, in which helminths can be excreted along with the bile.

However, most often the ascaris either goes through a full life cycle or dies under the influence of the immune system.

Roundworm in the intestines of the patient move freely, not attaching to its walls. For this reason, worms can be detected after the process of defecation, which greatly simplifies the primary diagnosis.

It happens that when carrying out laboratory research in the feces will find eggs of Ascaris, but this does not always happen.

Roundworm worms are roundworms, whose body structure is distinguished by a pointed spindle-shaped form. Moreover, in males and females form and internal structure   The bodies are similar, but in females the end of the body will have a characteristic bend. In just 24 hours, one female worm is capable of:

1. lay 200 and more thousands of eggs;
2. many of them will be fertilized.

For the development of roundworm eggs, the ground must be heated to a temperature of 24 degrees and above. How long do eggs remain viable? In such conditions, eggs live for about 12 years. You should also be aware that worms are resistant to freezing. The most common method of infection will become dirty hands if a person neglects the rules of personal hygiene. Hazardous factors are:

• water from rivers, ponds;
• unwashed vegetables, fruits;
• insufficiently processed food;
• labor activity in unsanitary conditions.

At risk of getting sick gardeners who are constantly in contact with the ground. To prevent infection, they should carefully monitor hygiene. It is possible that a child will become infected with ascaris if helminth eggs are present in the children's sandbox.

How does the roundworm life cycle

As noted, roundworm eggs, having penetrated into the human body, reach the small intestine, where they turn into larvae. They pass through the walls of the intestine, penetrate into the veins and, together with the blood flow, through the blood vessels of the small circle are quickly brought into the lungs of the patient.

They move sequentially from the blood:

1. into vesicles of the lungs, respiratory throat;
2. bronchi;
3. oral cavity.

They can affect not only the lungs, but also the brain, pancreas, liver and heart. Since the larvae travel through the capillaries, they take away from the blood a lot of nutrients and blood cells. Therefore, the disease ascariasis is almost always accompanied by anemia.

Symptoms

Such toxins in many cases provoke powerful allergic reactions   at the patient. In addition, after infection with ascaris, a person will notice symptoms of general intoxication of the body, accompanied by:

1. headaches, muscle aches;
2. fever.

You should know that roundworm, penetrating into the lungs, cause minor hemorrhages, which will be well visible on the X-ray. Fluorography in this case is very similar to images obtained from patients with tuberculosis.

Considering common symptoms worm infestationIt is necessary to focus on the following signs:

• moderate sclera yellowness;
• pallor of the skin and mucous membranes (due to anemia);
• anorexia, dyspeptic disorders;
• soreness in the stomach, intestines;
• bouts of vomiting, nausea.

In addition, a sick person has an upset stomach, he is worried about diarrhea, constipation, shortness of breath, general weakness in the body, a decrease in the body’s immune defense. The patient will complain of poor sleep at night, psycho-emotional instability, decreased performance, fatigue, allergic reactions with rashes on the skin.

Diagnostics and treatment methods

The medical institution will be tested the patient's blood and sputum from his bronchi. It is imperative that an x-ray be taken to determine the presence of infiltrates.

Consequences, complications, prevention

Besides the fact that roundworms seriously weaken the human condition, reduce resistance to various diseases, they pose a threat to pregnant women and young children.

Adult patients have worms that have evolved to adult individuals:

• lead to severe intestinal obstruction;
• that is treated only surgically.

Since getting rid of any helminths is an unpleasant process, it is best to take precautions. The first and most important recommendation of physicians is to wash hands thoroughly before eating, after doing dirty work, going to the toilet, the street, or public places.

When a person works with the ground, he should wash his hands with warm water and soap several times a day. Also, you should not allow children to play on dirty playgrounds, in polluted sandboxes.

The particular danger of ascaris in their invisibility. The first signs of invasion may resemble the symptoms of any other disease, and parasites for many years have not been felt. That is why it is extremely important to monitor the complex of suspicious symptoms in a timely manner, to consult a doctor for the treatment of a parasitic infection. The video in this article explains the nature of roundworm.