A neonate presents with hydrocephalus, bilateral chorioretinitis, and diffuse intracranial calcifications. The mother kept cats and gardened barefoot during pregnancy. By which route did the fetus acquire the infection?

• A Ingestion of tachyzoites through breastfeeding
• B Transplacental spread of bradyzoites from reactivated latent maternal infection
• C Ascending infection from the birth canal during labour
• D Transplacental spread of tachyzoites following primary maternal infection ✓

Explanation

Congenital toxoplasmosis follows primary maternal acquisition of Toxoplasma gondii during pregnancy: proliferating tachyzoites disseminate haematogenously and cross the placenta, producing the classic triad of hydrocephalus, intracranial calcifications, and chorioretinitis. Reactivation of chronic maternal infection rarely damages the fetus because preexisting immunity suppresses tachyzoites. Transmission does not occur meaningfully through the birth canal or breast milk, so those routes are incorrect.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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