Simplify the following text for a Grade 9 native English-speaking person.
Original: Toxoplasma gondii is a protozoan parasite that infects most species of warm blooded animals , including humans , causing the disease toxoplasmosis .
Simplified: Toxoplasma gondii is a species of parasitic protozoa in the genus Toxoplasma . The definitive host of T. gondii is the cat , but the parasite can be carried by many warm-blooded animals ( birds or mammals , including humans ) .