Epidemiology of neonatal infections.

Neonatal infections can be considered in three groups, those acquired antenatally, perinatally and nosocomially. For many years it has been recognized that antenatal infections may cause death or serious fetal damage, but only recently have the more subtle features of antenatal infection been recognized. These include particularly the ability of some (such as toxoplasmosis) to produce disease many years later. Perinatal infection is often the result of maternal carriage of organisms, usually asymptomatically, and a variety of treatment approaches including immunotherapy (for hepatitis B) and antibacterial prophylaxis (for chlamydia) are being used to reduce the short- and long-term morbidity associated with this route of neonatal infection. Nosocomial infection in the neonatal nursery, and particularly in the neonatal intensive care unit may again lead to longer term problems in the infant, and organisms such as staphylococci or salmonella acquired during neonatal life may cause invasive disease weeks or even months later. The prevention of nosocomial infection will depend on the synthesis of a variety of approaches to reduce the number and spread of organisms in the environment of the vulnerable neonate.