Whooping cough is a childhood disease. It is an inflammation of the breathing passages in the body. It can be serious, but most cases are mild.
The germs causing whooping cough are called Bordetella pertussis; whooping cough is medically known as pertussis. The infection usually spreads from a patient in the early stages of the disease to a susceptible child—one who has not been immunized or is not immune from already having had the disease. Pertussis vaccine is partially effective in giving immunity. The germs are carried by minute, droplets expelled into the surrounding air during coughs. Once these germs are inhaled, they lodge in the respiratory membranes of the throat and lungs. Here they multiply rapidly for a week or more—the incubation period.
At first, symptoms of an ordinary cold appear. The nose runs and mucus comes up from the throat. The sick person begins to cough, mostly at night. These symptoms indicate the beginning of the most contagious period. The coughing spells become more frequent, last longer, and are more severe. Eyes tear during prolonged coughs.
After about two weeks, there develop severe and explosive fits of rapid coughing followed by the "whoop" as deep breaths are desperately sucked in. During this period the violent coughing may cause vomiting.
Then, gradually, if no complications set in, the attacks become less frequent and less severe as the patient recovers. The disease usually lasts about six weeks.