Toxoplasmosis; pathogenesis and immunity

Toxoplasma gondii (T.gondii) is an obligate intracellular zoonotic protozoan that can be transmitted to humans through consumption of infected food, blood or organ transplantation, and vertical transmission to the fetus.While infections in healthy individuals are usually asymptomatic, they can be serious and life-threatening in immunocompromised patients, congenitally infected fetus and newborns.Infections in immunocompetent individuals are usually self-limiting, after the acute period, the parasite has the ability to persist in the bradyzoite form in the tissue cyst for years.In immunocompetent hosts, tissue cysts can persist for years and current treatments or the immune system cannot eliminate tissue cysts.Intact tissue cysts do not cause an immune response and an inflammatory response in the host.The immune response to Toxoplasma infection is complex.In immunocompetent hosts, infection is controlled by a strong innate and adaptive immune response that leads to elimination of the majority of parasites.Innate immunity is the first line of defence.Macrophages, neutrophils, dendritic