Lower Respiratory Tract Infections

Whooping cough is an infection caused by Bordetella pertussis. This bacterium adheres to the epithelial lining of the trachea and bronchi where it releases a toxin that interferes with ciliary motility. This subsequently causes accumulation of mucus which is overproduced as well. As a consequence, patients exhibit paroxysmal coughing, with a characteristic "whoop". In older children, the condition is relatively mild, but in infants under six months it may be a life-threatening infection because of the relatively small lung capacity of these children. Mucus accumulation leads to respiratory obstruction which may lead to death. Bordetella pertussis is a fastidious Gram-negative rod. It is typically isolated on blood-charcoal agar.

Antibiotics play little useful role in treating the acute infection. A vaccine is widely used. This works by conferring "herd immunity". The widespread use of vaccine reduces dramatically the number of potential victims in a population. In turn, this reduces the opportunity for the pathogen to spread so the number of pathogens declines. It is in this way that the most vulnerable - infants under six months, and who are not eligible for vaccination, can be protected from disease.