Perinatal Herpesvirus Infections

Maternal infection with a number of viruses during pregnancy and in the peripartum period can result in transmission of the virus to the fetus and newborn infant. In some cases these infections in newborn infant can result in significant morbidity and mortality, depending on the specific viral agent, the age of virus acquisition, and perhaps more importantly, characteristics of the maternal infection associated with transmission to the fetus or newborn infant. Each of these factors can contribute to both the incidence and outcome of infection in the fetus or newborn infant, but features unique to the natural history of each of these viral infections allow only a limited number of generalizations to be made about this group of infections. Perinatal infections can be divided into those acquired in-utero by the developing infant and present at birth (congenital infection) and those acquired at the time of birth (peripartum). A much smaller number of neonatal infections are acquired in the postnatal period through exposure to infected caretakers who are often individuals other than the mother. A list of viruses associated with perinatal infections is provided in table 1. These agents are listed in an approximate order of their frequency as causes of infection and disease in fetuses and infants in the US. However, the relative importance of these agents as a cause of disease in infants from underdeveloped countries and countries with transitional economies is not well documented. Undoubtedly, HIV and hepatitis viruses likely are more frequently observed in populations from non-first world countries, particularly as causes of perinatal infections. For this brief overview of perinatal infections, we will discuss neonatal herpes simplex infections as an example of perinatal infection and CMV as an example a virus that commonly causes both congenital and perinatal infections. PERINATAL HERPESVIRUS INFECTIONS