Human exposure to toxoplasmosis is common: it is estimated that aroung 60% of healthy adults worldwide are seropositive to ''[[Toxoplasma gondii]]''. The most common route of human infection is ingestion of oocysts in water or food contaminated by cat faeces, although consumption of undercooked meat containing tissue cysts also occurs. Contact with abortion products from infected ewes is a risk for pregnant women. An immune response occurs in response to infection, and tissue cysts form in several organs. These cysts may later reactivate in immunocompromised patients, for example those suffering from AIDS. If initial infection occurs during pregnancy, or if cysts reactivate at this time, ''Toxoplasma'' may infect the foetus transplacentally. As most mothers are exposed to ''Toxoplasma gondii'' early in life, and are immunocompetent, transplacental infection is seen infrequently. Transmission via blood transfusions or organ transplantation can also occur in man. | Human exposure to toxoplasmosis is common: it is estimated that aroung 60% of healthy adults worldwide are seropositive to ''[[Toxoplasma gondii]]''. The most common route of human infection is ingestion of oocysts in water or food contaminated by cat faeces, although consumption of undercooked meat containing tissue cysts also occurs. Contact with abortion products from infected ewes is a risk for pregnant women. An immune response occurs in response to infection, and tissue cysts form in several organs. These cysts may later reactivate in immunocompromised patients, for example those suffering from AIDS. If initial infection occurs during pregnancy, or if cysts reactivate at this time, ''Toxoplasma'' may infect the foetus transplacentally. As most mothers are exposed to ''Toxoplasma gondii'' early in life, and are immunocompetent, transplacental infection is seen infrequently. Transmission via blood transfusions or organ transplantation can also occur in man. |