Entamoeba Histolytica Life Cycle

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Entamoeba Histolytica is an infectious parasite found in the human intestine and several other primates. Furthermore, in specific chronic scenarios, it can reach to liver, brain, lung and other body organs by entering blood circulation. As a result, it has the capability of causing critical diseases like amoebiasis or amoebic dysentery.

Before moving on with entamoeba life cycle, first, you must know about its different forms. E. Histolytica is found in two different forms, and they are:

  • Magna or Trophozoite Form

This is the adult type of entamoeba which dwells in anterior portion of large intestine, which is the colon in humans. Moreover, it is similar to amoeba in terms of structure but distinguishes in parasitic means of life. Plasma lemma covers its body and cytoplasm is divided into endoplasm and ectoplasm.

Further, a single broad and blunt pseudopodium is formed out of ectoplasm. Also, the endoplasm comprises of food vacuoles and a single nucleus of spherical shape. Its nucleus contains outlying crown of chromatin chunks and also a nucleolus situated at the centre.

By continuous binary fission, trophozoites multiply in number in the intestine walls of a human being. However, some daughter E. Histolytica become adults while few stops growing. Hence, these small size trophozoites are termed as Minuta forms.

  • Minuta or Precystic Form

This form is comparatively small in size and remains at non-pathogenic state. It inhabits in the intestinal lumen and is scarcely present in tissues. Moreover, these undergo encystation and assists in transfer of parasites from one body to another.

Life Cycle

The life cycle of Entamoeba Histolytica gets completed in one body only (monogenetic).

Following are the steps of E Histolytica life cycle:

  • Encystment

Entamoeba, in its precystic form, stays in the lumen of intestine only, and they experience encystment. But before encystment, these parasites coil up, defecate food vacuoles and gather quite an amount of materials of food. Moreover, these food materials are in glycogen form and rod-like chromatoid fragments of black colour. Also, every parasite releases a colourless, narrow, circular, transparent and resistant cyst wall which surrounds the main body.

Furthermore, entamoeba cysts differ in size. The cytoplasm present in it is clear, and every cyst has one nucleus at this phase. One characteristic of E. Histolytica is the existence of chromatoid bodies, and they appear singly or in multiples of two or more. Moreover, the cysts’ nucleus always divides two times, such that each of them becomes tetra nucleate.

However, at this phase, cysts are infective to a new body (host), and the encysted forms eliminate with faecal matter of an individual.

  • Transmission to Another Host

Cysts which are infectious stays outside the host’s intestine in working mode for a considerable period, under suitable environmental conditions. Infection among new human bodies occur when they intake drinks and food infected with cysts.

  • Excystment

The trophozoites sustain on the intestinal products and enlarge to become trophozoites of succeeding generation. Also, these trophozoites remain in intestinal lumen for a certain period and may strike an attack on the intestinal walls and resume their life cycle. Furthermore, E. Histolytica is responsible for causing abscesses in lungs, liver and brain, non-dysenteric infections and amoebic dysentery.

Life Cycle of Entamoeba Histolytica Diagram

Below are several measures which may prove helpful in safeguarding human body from E. Histolytica causing diseases:

  • Hygienic elimination of faeces.

  • Appropriate sanitation and filtration of water and vegetables against dirt.

  • Proper cleaning of hands with soap or handwash before consuming food.

  • Preparing clean food and also cleaning the surrounding area of cooking.

  • Preventing food materials and drinks from the infection of flies, cockroaches, etc.

  • Avoiding eating undercooked or raw food.

Do It Yourself

Fill in the blanks:

E. Histolytica can cause fatal disease like _________ or _________.

By now, we hope that you have understood the life cycle of Entamoeba Histolytica. For further insight on the topic, or any other chapter of Biology, go through our extensive collection of study materials today. You can also install Vedantu’s app to access your notes with you anywhere.

FAQ (Frequently Asked Questions)

1. What does Entamoeba Histolytica feed on?

It survives on cells present in colon of human beings.

2. What are the steps involved in life cycle of Entamoeba Histolytica?

 The processes include –

  1. Encystment.

  2. Transfer to another body.

  3. Excystment.

3. How widespread is Entamoeba Histolytica?

It is a parasite that is known to have infected more than 45 million people throughout the world. Also, it is responsible for death of 55,000+ individuals each year.