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Abstract
Toxoplasmosis is one of the most common zoonotic diseases affecting humans and cause latent infection. About 30% to 65% of all people worldwide are infected with toxoplasmosis. It affects people with severely weakened immune systems such as those with AIDS. Illness may result from acute infection or reactivation of one occurred early in life. When a mother is infected with T. gondii during gestation, the parasite may be disseminated hematogenously to the placenta. The fetus becomes infected transplacentally or during vaginal delivery. If the mother acquires the infection in the first trimester and not treated, the risk of infection to the fetus is approximately 14-17%, and toxoplasmosis in the infant is usually severe. If the mother is infected in the second or third trimester and untreated, the risk of fetal infection is approximately 59 65%, and involvement is mild or inapparent at birth. Toxoplasmosis is asymptomatic in 80-90% of healthy hosts but rapidly progressive fatal disease in immunosuppressed patients. Congenital infection usually leads to more severe disease when it occurs in the first trimester and leads to a wide variety of manifestations in the fetus and infant including spontaneous abortion, still-birth, a live infant with classic signs of congenital toxoplasmosis such as hydrocephalus, microcephalus, cerebral calcifications and chorioretinitis. Some infants who fail to thrive from CNS involvement develop chorioretinitis. Others delivered apparently normal infant and develop chorioretinitis or symptoms of CNS involvement including learning disabilities, later in life. Diagnosis of toxoplasmosis in humans is made by serological, histological, or molecular methods, or by some combination of the above.