The role of established and emerging pathogens in respiratory disease

Mortality due to acute respiratory infection in otherwise healthy individuals in developed countries is relatively rare, with the exception of influenza and respiratory syncytial virus infections. However, respiratory infections have a significant morbidity impact in the family and work settings. The rapid identification of viral pathogens facilitates appropriate treatment choices and the management of nosocomial transmission. Despite the recent advances in the detection of respiratory pathogens using sensitive molecular techniques, only two-thirds of infections are consistently diagnosed. A multiplex PCR system was designed and implemented to screen a large number of respiratory samples for a comprehensive range of potential respiratory pathogens. The assay was easily modified to account for changes in circulating virus populations. The assays were used to investigate the role of respiratory viruses in a number of different populations. This study is unique in that it investigated a wide range of respiratory pathogens in a number of different populations and included healthy control groups. A longitudinal family study followed the natural history of respiratory infections, and demonstrated long term shedding of some recently recognised viruses such as bocavirus and the polyomaviruses, with little correlation to respiratory illness episodes. Asymptomatic, concurrent or sequential infections with recognised respiratory pathogens were recognised.