Toxoplasma Gondii Life Cycle


Toxoplasmosis is a flu-like, infectious disease caused by a parasite called Toxoplasma gondii parasite. The Toxoplasma gondii parasite is attracted to mostly warm-blooded animals and human beings. This disease has flu-like symptoms and spreads from consuming undercooked meat, sometimes if exposed to infected cat faeces. In the case of human beings, if a pregnant female has Toxoplasmosis, she can pass it on to her foetus. The suborder Coccidia includes microscopic, spore-forming parasites that fall under class Conoidasida. Since this parasite feeds on intermediate hosts like birds, animals like cats and even human beings, they are found in abundance all over the world. It has the ability to survive in different environments.

Let’s look at the life cycle of the Toxoplasma gondii parasite.

Life Cycle of Toxoplasma gondii:

The life cycle of parasite Toxoplasma gondii is different from most other parasites. While other insect life cycles include sexual stages of reproduction, this parasite has asexual and sexual stages of reproduction in felines such as cats. This parasite seems to spread faster amongst intermediate hosts.

  1. Oocyst – Stage 1 –

The parasite Toxoplasma gondii forms an oocyst which is a cyst that contains zygote of the parasite. The process of producing spores is called sporulation. The oocyst sheds multiple times and takes around 5 days to become infective. The intermediate hosts like cats and dogs get infected when they consume soil or mud that contains these oocysts. Once they infect a host, they enter the next stage, where they transform into Tachyzoites.

  1. Tachyzoite – Stage 2 –

Once an oocyst has entered the stomach of the animal (cat or dog), it forms into tachyzoites after ingestion. These tachyzoites attack the neural and muscle tissues and form other tissues known as the cyst bradyzoites.

  1. Bradyzoite – Stage 3 –

Bradyzoites are parasites formed in tissue cysts which are found in muscle cells and within cells of the nervous system. Animals like cats can be infected with this parasite if they feed on intermediate hosts who have tissue cysts like bradyzoites.


The infection caused by Toxoplasma gondii parasites prevails in many parts of the world. In human beings, the parasite forms tissue cyst in areas of eyes, brain and skeletal muscles.

Frequently Asked Questions on Toxoplasma gondii Life Cycle


What happens to humans if infected with Toxoplasma gondii parasite?

Once the parasite enters a human body, it causes a disease called Toxoplasmosis. This is a disease similar to the flu with symptoms like fever, body ache, headache and so on. Due to its mild symptoms, it is rarely known or treated. Diagnosing the parasite requires separate tests for detection.


Who are at higher risk of getting toxoplasmosis?

Pregnant mothers who have this parasite, pass it to their child in the womb. Therefore a child or infant whose mother has Toxoplasma gondii parasite, will get it too. People with weak immune systems are also highly susceptible to this disease.


How can I prevent toxoplasmosis?

By cooking food items like meat in safe room temperatures, wash and rinse vegetables and fruits before consumption. In the case of gardening, wear gloves as these parasites are found in soil in the form of oocysts.

To explore more information on Toxoplasma gondii and other parasites, register with BYJU’S Biology.

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