Ascarid is a fairly common helminth that parasitizes in the human body. It refers to roundworms and reaches impressive sizes - up to about 40 cm. This parasitic infection affects both children and adults. Ascaris in the human body undergoes several cycles of development. At each stage, these worms cause certain symptoms, their presence in the body is very harmful to health.
The development of ascarids occurs exclusively in the human body, the parasite can not live in animals. Eggs of these worms are found in the soil, there they mature and only then become infectious. That is why infection usually occurs due to neglect of hygiene rules. The cycle of ascarids begins when the invasive egg enters the body.
Migratory stage of development of ascarids
It is generally accepted to distinguish 3 cycles of development of this kind of helminths, we will consider consistently the entire life cycle of the roundworm. Once the egg enters the stomach, then there it is exposed to the corrosive effect of the acidic medium, as a result of which the protective shell is broken and the larva already hatches in the intestine, the so-called molt occurs.
The migration stage of the development of the human roundworm begins, the larva is very small, it penetrates into the intestinal wall and penetrates into the bloodstream, so the parasite spreads throughout the body. At the initial stage of development of the human roundworm, she eats serum, a little later she begins to eat red blood cells. They contain a lot of oxygen, as they are its carriers, and it is necessary for the further development of this helminth.
In search of the necessary amount of oxygen, the larva migrates to the organs, enters the liver, the heart, and then into the lungs. The life cycle of the roundworm does not always follow the classical pattern, sometimes parasites may linger in some organ and die there. But most often it's the oxygen starvation that leads the larva into the lungs. It changes its color due to lack of oxygen, it becomes more pale.
The cycle of development of ascarids causes the parasites to move to the lungs, they accumulate there and cause separation of sputum. The infected person begins to cough, as a result, the helminths get into the pharynx together with phlegm, there a part of the larvae is repeatedly swallowed up by the sick, and they again find themselves in the intestine. At this the migratory stage of development of the larvae ends, as a rule, it lasts about two weeks.
Intestinal stage of ascariasis
Usually the sequence of stages in the development cycle of the human roundworm is not disrupted. The migratory stage is replaced by the intestinal stage, exceptions are rare. If the parasite enters the intestine a second time, then here it will continue its development. Quite quickly the larva turns into an adult. Within a couple of months the worm begins to multiply actively. It develops in the small intestine and receives the necessary nutrition there.
This kind of helminthic invasion disturbs the intestinal microflora and causes various digestive disorders. Violated the process of digestion of food, as well as the absorption of nutrients, as a result of the patient receives less vitamins, because of this, anemia may occur.
Sometimes it happens that the sequence of development of the roundworm cycle changes slightly, that is, the parasite does not enter the intestine again, but begins its development in other organs. But there, as a rule, because of a shortage of nutrients, the worm quickly dies, but still can cause damage and inflammation of the organs.
How do the ascarids multiply?
The process of reproduction of a human roundworm is rather complicated. These parasites are of different sexes, they have typical signs for their gender. The female is always bigger than the male, but it has a hook at the end. The male is attached to the body of the female and so reproduction occurs. These worms are rather prolific, for example, an individual of the female genus may postpone about 240 thousand eggs per day.
The life cycle of such worms lasts from several months to a year, then the worm dies. During its short life the female can lay several tens of millions of eggs. All of them stand out together with the feces outward.
Maturing of eggs of ascarids
The next stage of development of the human roundworm occurs exclusively in the soil, until the eggs reach it, they will not ripen. To form a larva in an egg, certain conditions are necessary. For example, it is very important that the soil is moist, and that there is a direct access of oxygen, the temperature should be comfortable within 25 degrees.
If all the conditions are met, then the life cycle of the roundworm will follow the classical scheme. Eggs will mature in 17 days and will be ready to continue the cycle of their development already in the human body. But if they hit the ground at minus temperatures, their development will slow down, they will lie in the ground until favorable conditions come.
It is important to note that eggs have a five-layered shell, they are well protected from adverse external influences. For them, direct sunlight is harmful, as well as alcohol, gasoline and ether. If all the conditions are met, then eggs can lie in the ground for up to 10 years, waiting until their life cycle continues in the human body. The development of this type of worm occurs without a change of host.
How to avoid the development of ascariasis?
The description of the life cycle of the roundworm is completed, from the above it becomes clear that the parasite can not continue its development if it does not enter the body. That's why to avoid ascariasis, you need to know not only the cycle of the development of this disease, but also how the infection occurs.
Basically, infection occurs when a person does not follow the rules of hygiene, for example, does not wash his hands before eating. But there are other ways of transmission, namely:
- You can get infected if you eat not enough thermally processed food. For example, if there were soil particles on it, then an insufficiently high temperature will not destroy the eggs of parasites, and they will end up in the body.
- Contaminated reservoirs can also be a source of this parasitic infection. That's why you can not drink unboiled water from lakes and rivers, and you should not swim in polluted water.
- Very often the life cycle of parasites in the body begins with the fact that he ate unwashed vegetables and fruits from the garden. They often contain soil particles that are a breeding ground for parasitic infection.
- People who work for a long time in unsanitary conditions are often infected. They can get sick for years, because the population of worms in their body is constantly replenished.
The description of the life cycle of the human roundworm has come to an end, from all this we can conclude that every parasitic disease can become infected. That's why it is important to observe the basic precautions, just wash your hands, do not drink water from untested sources and do not eat unwashed vegetables and fruits. Ascaridosis is dangerous for its complications, massive infection can result in death.