[Epidemiology of acute upper and lower respiratory tract infections in children].

More than 200 antigenically distinct viruses have been documented as causes of sporadic or epidemic respiratory infections in infants and children. The lung itself is rarely sampled directly, and sputum representing lower-airway secretions can rarely be obtained from children. In addition culture of secretions from upper respiratory tract is not useful since the normal flora includes the bacteria commonly responsible for pneumonia. Clinical and radiology data only suggest the diagnosis. The development of techniques to detect antigens of the causative agent in nasopharyngeal secretions, nucleic acid by means of the polymerise-chain reaction assays has significantly improved the identification of the responsible pathogen and the choice of appropriate treatment. Since more 30 years rhinovirus, coronavirus, enterovirus, parainfluenza virus and respiratory syncytial virus were added to influenza, adenovirus and measles virus as causes of respiratory tract infections. This list of pathogens was extended last years with the discovery of human metapneumovirus, bocavirus, polyomavirus. In restricted patient groups, such as the immunocompromised, members of the family of herpesvirus have also been associated with respiratory disease.