Congenital toxoplasmosis

Congenital toxoplasmosis is an infectious disease caused by transplacental transmission of the intracellular parasite Toxoplasma gondii from a mother who acquires a primary infection during pregnancy (or, rarely, shortly before conception) to the developing fetus. It is not a genetic disorder but rather a congenital infection. The severity of fetal involvement depends largely on the gestational age at which maternal infection occurs: infection in the first trimester tends to cause more severe disease, while transmission rates are higher in the third trimester but typically result in milder or subclinical disease. Congenital toxoplasmosis can affect multiple organ systems, most notably the central nervous system and the eyes. The classic clinical triad includes chorioretinitis (inflammation of the retina and choroid), intracranial calcifications, and hydrocephalus, though the full triad is present in only a minority of cases. Other manifestations include microcephaly or macrocephaly, seizures, hepatosplenomegaly, jaundice, thrombocytopenia, anemia, a diffuse maculopapular rash, and generalized lymphadenopathy. Many affected infants appear asymptomatic at birth but may develop significant sequelae later in life, particularly chorioretinitis, sensorineural hearing loss, intellectual disability, and learning difficulties, if left untreated. Treatment of congenital toxoplasmosis typically involves a combination of pyrimethamine, sulfadiazine, and folinic acid (leucovorin), administered for a prolonged period, usually 12 months. Early initiation of treatment, even in subclinically affected neonates, has been shown to reduce the risk of long-term neurological and ophthalmological complications. Prenatal treatment with spiramycin may be used to reduce the risk of vertical transmission when maternal seroconversion is detected during pregnancy. Long-term follow-up with ophthalmological, audiological, and neurodevelopmental assessments is essential for all affected children.

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