Toxoplasmosis is usually an asymptomatic and innocent disease, but in fetuses and immunocompromised hosts it often takes a severe course. Toxoplasma gondii exists in host tissues as oocysts, tachyzoites, and cysts. The oocysts are formed in the lining cells of the ileum of the cat and are shed in the feces.1 The tachyzoites, which are the acute-phase agents, may invade the nucleated cells of all mammals. The tissue cysts contain up to 3000 bradyzoites, which remain alive for the life span of the host.
The oocysts in cat feces become infective in 1 to 5 days and may remain viable for a year. Mammals are infected by oocysts via vectors. Toxoplasma is also transmitted by infected meat, eaten raw or poorly cooked, unwashed/unpeeled vegetables and fruit, body secretions (ie, unpasteurized milk and blood transfusions), and transplanted organs.1
New aspects of this old parasitic disease that have recently come
Koskiniemi M, Lappalainen M, Hedman K. Toxoplasmosis Needs EvaluationAn Overview and Proposals. Am J Dis Child. 1989;143(6):724–728. doi:10.1001/archpedi.1989.02150180106030