ABSTRACT
Introduction The list of organisms that can cause disease in the respiratory tract is extensive and includes pneumococcus, haemophilus, group A streptococcus, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Mycobacterium tuberculosis. Important viruses to consider are influenza, parainfluenza, respiratory syncytial virus (RSV), and the ‘common cold’ rhinoviruses. In countries where vaccination programs are in place, diphtheria, whooping cough, and epiglottitis caused by Haemophilus influenzae b are uncommon. Where vaccination programs are poor these agents remain important as evidenced for example by the increase in diphtheria in parts of Eastern Europe in the 1990s.
