Bordetella pertussis is a bacterium that causes whooping cough, a highly contagious respiratory disease. It primarily affects children but can also infect adults. The bacterium attaches to the cilia in the respiratory tract, leading to inflammation and severe coughing fits, which can last for weeks. Transmission occurs through respiratory droplets when an infected person coughs or sneezes. Vaccination with the DTaP vaccine is the most effective way to prevent whooping cough. Early diagnosis and treatment with antibiotics can help reduce the severity of the illness and prevent its spread.