Jartti T et al. – A viral cause of pediatric respiratory illness is identifiable in up to 95% of cases, but the detection rates decrease steadily by age, to 30–40% in the elderly. The new viruses cause respiratory illnesses such as common cold, bronchitis, bronchiolitis, exacerbations of asthma and chronic obstructive pulmonary disease and pneumonia. Rarely, acute respiratory failure may occur. The clinical role of other new viruses, KI and WU polyomaviruses and the torque teno virus, as respiratory pathogens is not clear.