Roundworms in humans grow up to 35-40 cm. The larger ones are females. It is extremely rare for a male to reach this size. Its maximum length is 25-28 cm. The size of the roundworm depends on the age of the parasite, which can live in the human body for 3-4 years. There are also distinctive structural features of floors. Males have a curved tail tip that points toward the abdomen.
The main habitat is the small intestine. Ascaris has a characteristic feature - a smooth body surface. Sexually mature individuals are in constant motion - against the direction of peristalsis and movement of feces. They cannot attach to the walls of internal organs.
What to do in such a situation? To get started, we recommend reading this article. This article describes in detail methods of controlling parasites. We also recommend that you consult a specialist. Read the article >>>
The process of infection with roundworms
The main distributor of roundworms are people themselves. The feces of a person infected with helminthic infestation contain parasite eggs. They can survive outside the human body for 2-3 years.
If there is contact with the ground, the parasites acquire favorable “soil” for the development of human roundworm, ready to re-infect humans. The pattern of development of roundworm from an egg occurs in stages, during warm periods of the year. Therefore, signs of ascariasis in adults and children are observed more often from April to October.
The full development cycle of human roundworm begins with the egg phase. Some of them are fertilized. To begin their active growth, they need to go through certain stages of ripening in the soil. This is accompanied by air humidity of 4-8%, temperature of 14-37˚C, as well as a constant flow of oxygen.
A feature of the development of the parasite is its resistance to sudden cold snaps. If the air temperature drops during the ripening process, the helminths will not die. The roundworm's life cycle is suspended. In this state, eggs can remain for up to 8 years.
The development of roundworm to maturity occurs in the human body itself.
She can get there in one of the following ways:
- through body contact with the soil;
- eating poorly washed vegetables, berries or fruits;
- drinking tap water;
- with the consumption of meat and fish dishes that have undergone insufficient heat treatment.
Once in the body, the life cycle of the human roundworm moves on to the next stage of its own development. There are two of them - intestinal and migratory.
The migration cycle of roundworm development occurs through the circulatory system. The larvae are transported through the bloodstream to the liver, then to the heart and lungs. After this, they enter the throat. And this is again a direct path to the intestines. A secondary ingestion of the larva occurs, which, once in the intestine, develops into a sexually mature individual.
It takes up to 2.5-3 months for a sexually mature individual to mature. The development of the human roundworm occurs throughout its life. The average lifespan of an individual is 1-2 years. When it dies, the roundworm parasite leaves the intestines along with the feces. But self-healing occurs very rarely. Most often, more than one individual parasitizes the intestines. There is also a risk that a person will become infected with ascariasis again. No one is protected from such a “cycle”.
Features of the development of roundworm
The development cycle of such a helminth is considered a gradual process, which is carried out in two successive stages. Moreover, the duration of each of them can be 3-4 months.
The main stages of development of roundworm include:
- migration;
- intestinal.
Before the migratory stage of development of the worm begins, its eggs must fall into the ground. It is in the soil that there are optimal conditions for the development of larvae in eggs. Since parasite eggs are covered with a dense shell, they can easily withstand external influences and mechanical damage. However, they do not cope well with temperature changes. Therefore, many advise, to clean the soil from helminths, to water it with boiled water.
For the worm to continue to develop, it will have to penetrate the human digestive system. For infection, helminths use already fertilized eggs, on the surface of which there is a protective shell. They go through several stages of embryogenesis, as a result of which a small tadpole first develops, and then a mature larva appears. It can exist and develop without outside help.
Life cycle stages
Adult worms live in the lumen of the small intestine. Their lifespan ranges from 10 months to two years, after which they, or rather their remains, are excreted in the feces. The eggs of any roundworm (not just human ones) leave the body of the final host along with the feces. If during the course of the infection only a female lives in the body, then her eggs are infertile, and if only males, then the eggs do not come out at all.
Initially, fertilized eggs do not pose a threat, since they are still immature, and therefore non-invasive (non-contagious). First, the larvae should mature in them within about two weeks in the presence of a sufficiently warm and humid environment. During this process, the embryo goes through several stages: morula, gastrula, tadpole, larva. After this, the egg must be swallowed by the future owner, which usually happens along with contaminated food or water.
The entire life cycle of development of the human roundworm in the host’s body can be divided into two global stages:
- stage of helminth migration;
- intestinal stage.
Migration stage
Once in the lumen of the human intestine, the larvae are released from the protective shell and become about 0.2 mm long. The implementation of this process occurs due to the release of its own enzymes that can dissolve the outer coating. The presence of a special uncinate process makes it possible to firmly attach to the mucous membrane of the small intestine, after which the larvae pierce it and enter the bloodstream. Studies have also shown that migration is facilitated by the release of an enzyme related to hyaluronidases, which dissolves vascular tissue.
The penetration of roundworm larvae into the bloodstream causes their spread throughout the body. One of the first target organs is the liver. Then, after migrating to the heart, they enter the pulmonary circulation (pulmonary), thanks to which they reach the lungs. The larvae need oxygen to fully mature. Unlike mature worms, which this gas kills and this is one of the treatment methods.
In the alveoli of the lungs, the last two molting processes take place over the course of about 10 days, due to which each larva reaches 1.4 mm in length. Then they travel along the ciliated epithelium that lines the human respiratory tract, through the bronchi and trachea to the larynx, to be swallowed again. During this period, a cough may be observed as a response to irritation.
The larva thus returns to the small intestine, where it grows until it becomes an adult. But this is already the intestinal stage.
This complex process of helminth maturation is an integral part of their life. The duration of the migration phase for ascariasis is on average 14-15 days.
Intestinal stage
The main parameter characterizing this stage is the maturation of roundworm larvae and their transformation into an adult. At the same time, the worms reach impressive sizes - females become up to 40 cm long with a diameter of 5 mm, and males - 25 cm and 3 mm, respectively.
They then live, mate and lay eggs inside the intestines for up to 1.5 years.
The duration of the disease is due to constant self-infection. Since reproduction within the host is not possible for roundworms, as is the case for most other worms. Considering this factor, a person may suffer from ascariasis for several years.
From the moment an roundworm egg enters the human body until the first egg laying by an adult female, an average of 80 days pass.
In the initial period of its development and maturation, the immature roundworm feeds by absorbing human blood serum. During its maturation, red blood cells become the source of nutrients for the parasite.
Ascariasis is one of the most common parasitic diseases
There is an opinion that after the end of the life cycle, helminths independently leave the human body. This statement is wrong. Such migration paths of roundworms determine their uniform distribution throughout the body. Therefore, the appearance of combined inflammatory processes in the gastrointestinal tract, heart, and lungs is not accidental. Among the main clinical manifestations of ascariasis are myocarditis, pneumonia, bronchitis, jaundice, and gastrointestinal bleeding.
Stages of development of roundworm
The life cycle of roundworm development consists of several stages. It is recommended that you familiarize yourself with them in advance in order to better know the features of helminth development.
Migration stage of development
The migration stage differs from other stages in its duration, since it is during the migration period that the main development of the worm occurs. The parasite first enters the small intestine of the host. To do this, it gradually moves through the gastrointestinal tract. In the initial stages of development, roundworms will be in the intestines. The parasite is completely protected from external mechanical influences and from gastric juice. Therefore, developing in the human body, eggs and larvae are completely safe.
Migration of larvae through various organs
When larvae emerge from the eggs, they begin to penetrate various organs of the body. First, the pest, 0.3 millimeters in size, penetrates the intestinal walls. With the help of hooks located on the head, they enter the mucous membrane and penetrate the capillaries. This helps young individuals enter the circulatory system, through which they enter the liver. While in this organ, the larvae feed on red blood cells and gradually develop.
Then the parasites penetrate through the veins into the ventricles of the heart. Due to constant blood circulation, the larvae cannot stay in the heart for long, and they are pushed into the lungs, where the roundworms stay for a week and a half. During this time, the larva completes the second stage of molting.
Re-ingestion of larvae when coughing
From the respiratory organs, the mature larva tries to penetrate the larynx. To do this, the parasite begins to irritate the mucous membranes of the respiratory tract, which causes inflammation in them. As a result, the person begins to cough, and the roundworm enters the larynx. Then, along with sputum, the worm is re-swallowed and enters the digestive system.
Intestinal stage
The larvae that have entered the intestines for the second time begin the incubation period again, which will not end until the roundworm has fully matured. During the intestinal stage, the parasite actively moves through the small intestine in search of food masses.
In 2-3 days of active feeding, the length of the worm can increase to 30 centimeters in females and 40-45 centimeters in males. When the development of roundworms ends, they begin the reproduction stage. Adults live in the intestines for about 2-3 years, after which they die and pass out of the intestines along with feces.
Maturation of roundworm eggs
The maturation of helminth eggs is influenced by several factors that should be familiarized with in advance.
Temperature
The rate of egg maturation directly depends on the ambient temperature. Indicators of about 20-25 degrees are considered optimal. In such conditions, worms are able to grow within 10-15 days. However, they also develop at temperatures of 5-10 degrees. With such indicators, the duration of their maturation increases to 30 days.
Soil moisture
Also, the duration of development of roundworm is affected by the level of soil moisture. In the summer, well-moistened soil promotes the maturation of eggs, since low humidity can lead to their death. In spring, when the air temperature is below 30 degrees, eggs develop well even in average humidity.
Oxygen access
The amount of oxygen in the soil can also affect the ripening process. In soils that are saturated with oxygen, the development of roundworm slows down. Their eggs develop better in dense soil with poor air permeability.
Routes of infection
Ascariasis is a disease of “dirty hands”. Neglect of personal hygiene rules significantly increases the risk of infection with roundworms. The eggs of these parasites remain in the soil for a long period.
The most common causes of infection:
- drinking water from questionable reservoirs;
- inadequate cleansing of fruits and vegetables;
- ingestion of certain foods that are insufficiently thermally processed;
- working in unsanitary conditions;
- failure to comply with hygiene rules.
- children's games in the sandbox.
The risk group includes those who are fond of gardening and are constantly in contact with the soil. To prevent parasitic infection, you need to wash your hands as often as possible.
Harm from roundworms
Adult roundworms can cause intestinal blockage, damage, and indigestion.
The waste products of roundworms are poisonous, which leads to poisoning of the body, which manifests itself through a rise in temperature, vomiting, irregular heartbeat, etc.
Ascaris larvae migrating with the bloodstream can damage internal organs (liver, pancreas); when the larvae pass through the walls of the lungs, blood may appear when coughing.
What are the consequences of having roundworms in the human body?
After the parasite penetrates the intestines, the incubation period is one and a half months.
In the initial stages of worm development, an infected person exhibits the following signs that indicate the presence of roundworm:
- vomiting with nausea;
- sudden weight loss;
- general weakness;
- dizziness;
- tingling in the intestinal area;
- loss of appetite;
- apathy.
The characteristics of the manifestation of symptoms depend on the number of helminths and the degree of organ damage. For example, if a large number of worms are in the liver, patients develop blood clots in the stool and develop jaundice.
In some patients, due to human roundworm, obstruction occurs, which leads to constipation and abdominal pain.
The most dangerous thing is if the parasites have settled in the respiratory organs, since in this case they are not easy to recognize. The symptoms that appear are reminiscent of colds, so people do not even assume that they have helminths. If the respiratory system is not cleared of worms in a timely manner, complications may arise in the form of pulmonary edema.
Treatment and prevention of human roundworm infestation
Treatment of any helminthic infestation 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 and starchy foods during treatment. It is necessary to eat cereals and cooked vegetables, which stimulate intestinal motility. After this, it is advisable to conduct a course of carrying therapy.
To do this, it is necessary to conduct a single course with the use of laxatives. It is better to take herbal preparations with a carrying effect. These include “Senadexin” - a portable remedy based on the leaves of senna - a plant with a laxative effect. After this course of cleansing therapy, they move on to treating the helminthic infestation itself. Antihelminthic drugs are used.
- Pyrantel is an anthelmintic drug that acts against human roundworm by depolarizing the membranes of muscle cells of worms, which contributes to the death of mature forms of roundworm. The drug is available in the form of tablets and suspension. The dosage of the drug for children is 250 milligrams up to six years old, and over six years old – 500 milligrams. For adults in the treatment of roundworms, a dose of one gram is recommended, that is, four tablets per dose. Possible 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.
- Vormil is an anthelmintic drug whose main active ingredient is albendazole. The mechanism of action of the drug is to disrupt the metabolism of roundworm cells. The advantage of this remedy is that albendazole acts both on the intestinal form, that is, on the adult, and on 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 symptoms.
Release form
Prevention of infection with human roundworm can be specific and nonspecific. Specific prevention is the use of anthelmintic drugs that have activity against roundworms for prophylactic purposes. To do this, it is necessary to take anthelmintic drugs twice a year; for children, half the therapeutic doses can be recommended. You can use any anthelmintic drugs - mebendazole, albendazole, Pyrantel.
Nonspecific prophylaxis should be used by all people, especially children should be monitored. Before eating, be sure 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, but to allow food to undergo sufficient heat treatment. For good digestion and reducing the possibility of roundworm infestation, proper nutrition is necessary, which increases local immunity and the anthelmintic capabilities of the intestines.
