Poliomyelitis in the fetus and the newborn. A comment on the new understanding of the pathogenesis.

A survey of the literature shows that although poliovirus may be recovered from fetuses whose mothers have paralytic poliomyelitis, there is no evidence that the fetuses themselves are affected. It is suggested that if postnatal poliomyelitis results from an autoallergic response not developed in the fetus, then poliovirus cannot enter the CNS of the fetus. When a mother has paralytic poliomyelitis at delivery the neonate has a 40 per cent chance of poliomyelitis, with a case fatality rate of about 50 per cent. It is suggested that most of these neonates become infected by virus entry into the exposed olfactory and nasal nerve endings after the membranes have burst. This would explain the very short incubation period and the high case and case fatality rates.