Toxoplasma gondii

Toxoplasma gondii is a single-celled parasite that causes toxoplasmosis and infects humans and many other warm-blooded animals. Cats and other felids are its definitive hosts, where sexual reproduction occurs.

Toxoplasma life cycle: The sequence of sexual and asexual stages through which Toxoplasma gondii reproduces and spreads. It links felid intestinal reproduction to parasite stages that infect other animals.
Toxoplasmosis: An infectious disease caused by Toxoplasma gondii, often mild but potentially severe in vulnerable people. It is the disease produced when this parasite infects a person or animal.
Definitive host: A host in which a parasite undergoes sexual reproduction or reaches sexual maturity. Felids are Toxoplasma gondii’s definitive hosts because sexual reproduction occurs in their intestines.
Toxoplasma gondii and behavior: Research on whether Toxoplasma gondii infection alters behavior in animals or humans. Rodent behavior changes are documented, while proposed effects in humans remain contested.
Oocyst: A durable, environmentally resistant stage produced by certain parasites, including Toxoplasma gondii. Shed in felid feces, oocysts can contaminate soil, water, and food.
Congenital toxoplasmosis: Fetal or newborn infection with Toxoplasma gondii acquired during pregnancy. A new maternal infection can cross the placenta and harm fetal development.
Intermediate host: A host in which a parasite develops without undergoing sexual reproduction. Humans and many other animals carry asexual Toxoplasma stages as intermediate hosts.
Toxoplasma gondii and mental disorders: Research into possible associations between Toxoplasma gondii infection and psychiatric conditions. Studies report associations, but causation and the size of any effect remain unresolved.
Tachyzoite: A rapidly multiplying form of Toxoplasma gondii active during acute infection. Tachyzoites spread through tissues during the early phase of infection.
Toxoplasma retinochoroiditis: Inflammation of the retina and choroid caused by Toxoplasma gondii infection. This parasite can cause recurrent eye disease, including sight-threatening lesions.

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