Toxoplasmosis Toxoplasma Cat ingests bradyzoites in tissue cysts in gondii animals,usually mice. Bradyzoites in tissue cyst (usually 10 to 100um Tachyzoites in diameter) (2 x 7um) ①Immature oocyst If humans eat Definitive host is shed in undercooked cat feces. meat containing tissue cysts,they may become Immature infected. oocyst M Sporozoites from ingested oocysts Sporogony invade animal tissue and develop into bradyzoites within tissue cysts,or into tissue-invading tachyzoites. Mature oocyst If a pregnant (10-12um) woman accidentally ingests oocysts (contacted when Intermediate changing a cat litter host box),prenatal infection of the fetus may occur Sporocyst Sporozoite Mature oocyst develops by sporogony and contains two Oocysts can infect many hosts,including mice sporocysts,each with four domestic animals,and humans,via ingestion. infective sporozoites. Figure 23.23 • Toxoplasma gondii Toxoplasmosis Figure 23.23