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Limitations in the immunologic response predispose the infant to certain viral and bacterial infections acquired during the prenatal, perinatal, and immediate postpartum periods. The development of the immune system and the mechanisms of response to both bacterial and viral infections are discussed in Chapter 182. Common viral and bacterial infections of neonates are discussed in this chapter.
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NEONATAL VIRAL PATHOGENS
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Viral pathogens can infect the fetus or neonate in utero via transplacental or ascending transmission of microorganisms; in the peripartum period at delivery by passage through an infected birth canal; or in the postpartum period by acquisition within the first several weeks of life. Human cytomegalovirus (CMV) and rubella virus can cause significant sequelae when acquired in utero, whereas herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) and enteroviruses can cause life-threatening disease when acquired in the peripartum and postpartum periods.
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The usual timing of transmission, clinical presentation, diagnosis, treatment, and prevention of common neonatal viral infections are discussed in the following sections and summarized in Table 225-1.
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PATHOGENESIS AND EPIDEMIOLOGY
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HSV infections can be acquired in utero (5%) or in the peripartum (85%) or postpartum (10%) periods. Peripartum or postpartum disease can be classified as disseminated disease involving multiple visceral organs, including lung, liver, adrenal glands, skin, and eye, ...