An infant with complex malformations of the central nervous system is described. The abnormalities included ependymal damage, aqueduct forking, hydrocephalus, and neuronal heterotopias; agenesis of the cerebellum, pontine, and inferior olivary neutrons; agenesis of the optic and olfactory systems and corpus callosum; and a highly unusual course of the corticospinal fibers in the spinal cord. Immunohistochemical test results showed the presence of influenza virus antigens in the brain. Possible pathogenetic mechanisms are presented.