Life Cycle Of Lamblia In The Human Body

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Life Cycle Of Lamblia In The Human Body
Life Cycle Of Lamblia In The Human Body

Video: Life Cycle Of Lamblia In The Human Body

Отличия серверных жестких дисков от десктопных
Video: Giardiasis - Giardia Lamblia 2023, February
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This type of parasite, like giardia, or lamblia, as everyone used to call them, is known to many. Every day, a large number of people around the world are infected with a disease such as giardiasis. The life cycle of lamblia, its varieties and ways of penetration into the human body - let's talk about all this in more detail.

Content

  • 1 Development
  • 2 How are lamblia transmitted
  • 3 Types of lamblia
  • 4 Why are lamblia dangerous

Development

The pathogen mainly enters the human body by the oral route, that is, through the mouth. Further, the cyst of lamblia (passive and stable form of life of the parasite), after passing through the digestive tract, enters the duodenum. It is there that it goes through the process of division, after which it becomes mobile and goes further - into the small intestine. There, lamblia and parasitize most often, they attach to the intestinal mucosa and feed on metabolic products.

The breeding scheme for these parasites is very simple. The process of division of lamblia occurs in a longitudinal manner, that is, the parasite is divided in two. Thus, giardias multiply very quickly. For example, if there are 100,000 parasites now, then in 8-10 hours their number will double, that is, there will be 200,000 of them, and so on.

Giardia completes its life cycle in the large intestine. She again goes into a cyst state, since the environment of the large intestine is not suitable for the full-fledged vital activity of the parasite, and he tries to protect himself with a shell. In the form of these same cysts, lamblia and go out with feces into the environment. Thus, the life cycle of parasites is closed. In this form, lamblia are pathogenic microorganisms, they are dangerous to humans.

A person infected with giardiasis can excrete hundreds of millions of cysts in one act of defecation. For comparison, only a few tens of units are enough to become infected. Cysts are stable in the environment. Thanks to their dense shell, they are able to withstand both low and high temperatures, high humidity, or, conversely, drought. If mobile individuals of lamblia - trophozoites - have entered the environment, they die almost instantly, since they are not able to live in this form outside the host's body.

How are lamblia transmitted

There are several mechanisms of infection with lamblia:

  1. Contact-household - infection through household items that have parasite cysts: bedding, care items, children's toys, etc.
  2. Fecal-oral - contact with objects that may have come into contact with feces infected with cysts.
  3. Nutritional - eating unwashed vegetables and fruits.
  4. Aquatic - swimming in bodies of water, especially with stagnant water, drinking untested or tap water.
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It also happens that the fetus in the womb of an infected mother is also infected with lamblia. But such cases are rare.

The main source of infection is a sick person or animal.

Types of lamblia

Let's consider each form of life of the parasite in more detail. As mentioned earlier, there are only two of them - an immobile form or cyst, and a mobile or vegetative - trophozoite. The transition from one type of parasite to another, and then vice versa, is the full life cycle of lamblia development.

Cyst

This species is an oval, slightly pear-shaped individual. Cyst sizes can vary: length - 1016 microns, width - 6-10 microns.

The cyst has two nuclei, they are located in the cytoplasm, there is also a spiral flagellar apparatus. Microscopically, the contour between the membrane and the protoplasm is very clearly visible. And it is this feature that distinguishes Giardia cysts from the same forms of other microorganisms.

Cysts are known to be persistent in the environment. For example, in humid climates, individuals can live up to three months. In stagnant water - lakes, ponds, cysts live from one and a half months to four, provided that the water temperature does not drop below four degrees. This type of parasite also tolerates hot summers with ease. If cysts end up on the surface of products, they can remain there for up to a day. And if it's a damp basement, then a week or more.

This form of giardia, unfortunately, does not die from exposure to chlorine-containing disinfectants; only thermal exposure or boiling can destroy them. Temperatures above 55 ° C are fatal for cysts.

Trophozoite

It is a vegetative form of the Giardia species. As soon as the cyst enters the stomach, its membrane is broken down by the action of gastric juice. Giardia is already entering the active phase. Its structure is the same, the shape is pear-shaped, but the size is slightly larger than that of the previous form. There can be up to a million microorganisms per 1 square centimeter of the human intestine. In this form, lamblia and harms the body.

A person's immunity is significantly reduced, he loses weight, signs of intestinal dysbiosis appear. This form of lamblia is very mobile, it does not parasitize only in one place of the intestine, but moves with ease and causes great damage to all parts of the intestine.

Why are lamblia dangerous?

According to statistics, 30% of the world's population are carriers of giardia. And more than half of these people do not even know about this parasite inside themselves. In most cases, this microorganism does not make itself felt for a very long time, since it does not cause the owner such discomfort that he would pay attention to, and a person's life goes on as usual.

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People have been living with giardiasis for decades and are direct sources of infection, and they do not notice the symptoms. Then why is giardiasis dangerous?

It's all about the human immune system. If the immunity is strong enough, then the body independently copes with pathogens. If the immune system is weakened by various factors (concomitant infectious diseases, pregnancy, etc.), then there is a risk of serious consequences of giardiasis.

Again, if the immune system copes with the attack of microorganisms, then this process ends on its own and does not require specific treatment. Sometimes the process turns into chronic enteritis - inflammation of the mucous membrane of the small intestine. Usually, the disease is sluggish, asymptomatic, but its danger lies in the fact that one or another part of the intestine may simply atrophy over time.

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And when in connection with this problem intestinal functions are disrupted, the disease is found. The inflammatory process can spread to the stomach, after which gastritis develops.

In general, all pathogenic effects can be divided into three general groups:

  1. Mechanical effect - irritation of the mucous membranes of the small intestine, duodenum, disturbance of the digestive and excretory functions of the gastrointestinal tract occurs. The absorption of fats and vitamins into the intestinal wall becomes difficult or completely stops. Concomitant diseases of the digestive system may also worsen.
  2. Toxic or allergic - the human body is poisoned with toxins and other products of the vital activity of parasites. Often against this background, acute allergic reactions occur - skin rashes.
  3. Nutrition of lamblia at the expense of the owner. Due to the constant lack of nutrients, most of which are absorbed by parasites, the body is depleted over time. A person begins to lose weight, and the weight is not gained even with increased nutrition. This symptom is a direct indication for testing for giardiasis.

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