Viral Infections

Viral infections may occur during pregnancy, when the brain is developing, during birth, or within the first days to weeks after birth. This chapter describes the clinical and neuroimaging features of the most common congenital and postnatally acquired viral infections that can affect the fetal and neonatal brain. Cytomegalovirus is the most common congenital infection and can be associated with hearing loss and malformations of cortical development when occurring in the first trimester. Toxoplasmosis, a protozoan parasite, can lead to antenatal hydrocephalus. Postnatal infections are especially likely to affect the white matter, with a very similar pattern of injury for enterovirus, parechovirus, and rotavirus. The prognosis depends on the time of onset for the congenital infections and on the gestational age for the postnatal infections.