NEW RESPIRATORY PATHOGENS

Key words: Respiratory infections, Etiology, Human metapneumovirus, Human bocavirus, Simkania negevensis

Acute respiratory infections represent the most common disease during childhood in both developing and developed countries and although the majority of these infections are limited to the upper respiratory tract, lower respiratory tract infections are the main cause of morbidity, mortality and hospitalization in infancy all over the world. The etiology of respiratory infections often remains unknown, thus suggesting that unknown respiratory pathogens have existed for a long time, even though the negative findings and the variability in agent-specific incidence rates also depend on methodological differences of the published studies. Determining the etiology of these diseases is a problem in the pediatric age, because obtaining adequate samples for the microbiological detection is not often simple and many diagnostic tests are not always sensitive enough to identify the etiological agent. Recent progress in epidemiological research and in molecular biology, as the introduction of polymerase chain reaction performed on samples from the upper respiratory tract in which viruses and atypical bacteria are not commensal, has enabled the quick recognition and identification of many respiratory emerging pathogens. The present review firstly introduces some of the new recent respiratory pathogens, then focuses on three individual “emerging” and “new” viral and bacterial microorganisms, such as Simkania negevensis, human metapneumovirus and human bocavirus.