Infections of the Newborn General ConsiderationsNewborns are special! They are exposed to several diverse environments during their intrauterine, perinatal, and postnatal lives. Because of this, and their relatively immature state of physical and immunological development, they have infectious disease problems that deserve special emphasis. In fact, there are textbooks exclusively devoted to infectious diseases of the fetus and newborn. Do not worry, this chapter will not attempt to be comprehensive in every detail, but rather focus on the commonest problems.
Newborn Environments (Fig 3-1)The first world the fetus encounters is unique in several aspects.Intrauterine. The ideal isolation room-or is it? There is no problem with airborne infection and direct contact with infected persons is. impossible. Maternal immunity is altered so that tolerance is pronounced, allowing the fetus to persist without immunologic challenge, in most cases. Contact between the mother's environment and the fetus is maintained and controlled via the placenta and umbilical cord, which are generally effective in limiting in utero antigenic exposure of the fetus. Nevertheless, breakthroughs occur. A common example is congenital cytomegalovirus infection, probably the most frequent congenital infection. Other maternal infections in the first trimester (e.g. influenza, measles, tuberculosis, etc.) have been associated with abortion and fetal death. These severe outcomes may be nature's way of avoiding horrendous congenital anomalies. In fact, these infections can be likened to lethal mutations, since they occur so early in embryonic development.