Whooping cough, medically known as pertussis, is a highly contagious bacterial infection that affects the airways. It gets its common name from the "whoop" sound that some infected children make when they take a deep, gasping breath after a severe coughing fit. The infection is caused by the bacterium Bordetella pertussis , with research suggesting that as few as 140 bacterial cells may be enough to cause infection. The bacterium spreads through infected droplets , which are released when an