Selected nosocomial viral infections.

A nosocomial viral infection is defined as a viral infection the onset of which occurs when the patient has been hospitalized longer than the incubation period of the virus. Viruses account for about 5% of all nosocomial infections. Viral cross-infection is most common in infants and children but also occurs in other groups, including the elderly, institutionalized persons of all ages, immunocompromised hosts, and patients with underlying chronic pulmonary, renal, or cardiac disease. These infections are associated with extended length of hospital stay and considerable morbidity and mortality. The spectrum of nosocomial viruses is wide and includes blood-borne, respiratory tract, and enteric pathogens, among others. This review will discuss the clinical characteristics, transmission, and control of the common nosocomial respiratory viruses: respiratory syncytial virus, varicella zoster virus, influenza virus, adenovirus, parainfluenza, and rubeola.