Pathogens Viruses: cause 80-90%/ of childhood respiratory infections. The most important are the respiratory syncycial virus(rsv, rhinoviruses, parainfluenza influenza and adenovirus, an individual virus can cause several different patterns of illness, e.g. RSV can cause bronchiolitis, croup, pneumonia or a common cold. The important bacterial respiratory pathogens are Streptococcus pneumoniae and other streptococci Haemophilus infiuenzae bordetella pertussis which cause whooping cough, and mycoplasma pneumoniae. Mycobacterium tuberculosis remains an important pathogen. Some pathogens cause predictable epidemics, such as RSV bronchiolitis every winter, whereas others, e.g. pneumococcus, show little seasonal variation.Pathogens ◼ Viruses: cause 80-90% of childhood respiratory infections. The most important are the respiratory syncycial virus (RSV), rhinoviruses, parainfluenza, influenza and adenovirus. An individual virus can cause several different patterns of illness, e.g. RSV can cause bronchiolitis, croup, pneumonia or a common cold. ◼ The important bacterial respiratory pathogens are Streptococcus pneumoniae and other streptococci, Haemophilus influenzae, Bordetella pertussis which cause whooping cough, and mycoplasma pneumoniae. Mycobacterium tuberculosis remains an important pathogen. Some pathogens cause predictable epidemics, such as RSV bronchiolitis every winter, whereas others, e.g. pneumococcus, show little seasonal variation