WHAT IS THE LIFE CYCLE OF AN ENTAMOEBA HISTOLYTICA LIKE? - BIOLOGY - 2025

The life cycle of an Entamoeba histolytica develops and completes in a single host; that is, it is a monogenetic amoeba. This is a pathogenic amoeba that causes a gastrointestinal disease known as ambiasis.

Entamoeba is a parasitic organism that lodges in the large intestine and colonizes it, causing internal inflammation.

Amebiasis is characterized by pain in the abdomen, diarrhea with the presence of blood and, if it worsens, produces an abscess in the liver.

Amoebas are protozoa. This word means "little animal". There are about 65,000 classified types of protozoa in the world.

This large number of species share common characteristics; however, they also differ from each other.

One of the fundamental differences is the life cycles. According to the species of protozoa, the multiple morphological stages of development will be different.

The 5 phases of the life cycle of a

1- Stage of infection

This amoeba remains inactive outside the host. It can be said that it begins in a pre-cystic stage.

These cysts come from a diseased host that expels them, almost always, via the feces. The host must be in contact with contaminated feces to become infected. The cysts are rounded and measure 10 to 15 microns.

2- Hatching stage

This stage begins when the host is in contact with the cysts or eggs and consumes them. This can happen by eating or drinking contaminated food or water.

There is also contact when handling fecal material and eating, or putting hands in the mouth without prior disinfection.

These cysts have the ability to resist hydrochloric acid from the stomach, unlike the adult amoeba known as a trophozoite. They also resist chlorine in water.

When they reach the small intestine, a process called excystation occurs, which is the cell division of the cyst, which goes from having four nuclei to having eight. This subphase is known as a transient metacystic state.

Cell division continues and eight trophozoites hatch from the cyst. The trophozoite is moderately elongated and can reach 18 to 40 microns. It does not have a fixed shape because the cell walls constantly change their contour.

3- Multiplication stage

At this stage the true infection begins: the amoebae begin their journey from the small to the large intestine and colonize both tubular organs.

During that time, the trophozoites sustain themselves by actively eating cell debris.

They also begin their reproduction, which is why they also encyst and this process emerge new trophozoites.

Entamoeba reproduces by a process called binary fission, having a very high multiplication rate.

4- Stage of excretion

Both eggs and adult amoebas can be excreted in the feces, ready to contaminate another host.

Entamoeba histolytica may remain in the intestine without causing symptoms of infection, that is, asymptomatically.

Despite this, in this period the host is able to excrete enough cysts to infect other people.

5- Invasion stage

When the Entamoeba histolytica colony gets out of control within the host, it irritates and destroys the gastrointestinal walls.

It also leaves the intestine and invades other organs such as the liver, lungs, and brain. This is the cause of the symptoms of amebiasis.

References

1. ENTAMOEBOSIS or AMIBIASIS - Resources in Parasitology - UNAM. (2017). Facmed.unam.mx. Retrieved December 4, 2017, from facmed.unam.mx
2. infectious, E., & AMEBIASIS - Síntomas, C. (2017). AMEBIASIS - Symptoms, Causes and Treatment »MD.Saúde. Mdsaude.com. Retrieved December 4, 2017, from mdsaude.com
3. Life Cycle of Entamoeba Histolytica (With Diagram) - Parasitic Protozoa. (2017). Zoology Notes. Retrieved December 4, 2017, from notesonzoology.com
4. Life Cycle & Pathology of Entamoeba histolytica. (2017). Msu.edu. Retrieved December 4, 2017, from msu.edu
5. The Structure and Life Cycle of Entamoeba (With Diagram). (2017). Biology Discussion. Retrieved December 4, 2017, from biologydiscussion.com