What is whooping cough (Pertussis)?
Whooping cough (pertussis) is a highly contagious bacterial infection of the upper respiratory system - specifically, the area where the nasal passages meet the back of the throat (nasopharynx). The infection causes irritation in breathing passages, resulting in severe coughing spells. The illness has three distinct stages and can last months. Pertussis, also known as
whooping cough, is caused by infection with the Bordetella pertussis bacteria. The infection is spread through the air by droplets from the breath of an infected person. The incubation period is usually 7 days.
Whooping cough can affect people of any age. Prior to widespread immunization, the disease was most common in infants and young children. Now that most children are immunized before school age, a higher percentage of cases are seen among adolescents and adults. However, about 40% of cases still occur in infants younger than 6 months of age. Early immunization can usually prevent this serious disease, which can sometimes be fatal or lead to permanent disability when it affects babies.
The bacteria invade the nose and throat, the breathing tube (trachea), and the lungs. The infection usually lasts 6 weeks. It starts with symptoms similar to the common cold, and progresses to spasms of coughing after 10 to 12 days. The cough is characterized by 2 or 3 repeated coughs without inhaling. Typically, the person's face becomes redder with each cough, then subtly bluish. In children, the coughing spasm often ends with a characteristic "whoop" when breathing in. The whoop is rare in patients under 6 months of age and adults. It is most often seen in children between 6 months and 7 years old. Very young children, older kids, and adults usually just have severe cough spasms (several in a row) that may cause vomiting. The child may momentarily lose consciousness at the end of a coughing spell. During this stage, there is heavy mucus production. Coughing spells may lead to vomiting. Pertussis should always be considered when vomiting occurs with coughing. In infants, choking spells are common.
Whooping cough is characterized by a cough, fever, sneezing, and runny nose. After several weeks the cough changes character, with paroxysms of coughing followed by an inspiratory "whooping" sound. Coughing fits may be followed by vomiting, which in severe cases leads to malnutrition. Other complications of the disease include pneumonia, encephalitis, and secondary bacterial superinfection.
The disease is spread by contact with airborne discharges from the mucous membranes of infected people. Treatment of the disease with antibiotics (often erythromycin or chloramphenicol) results in the person becoming less infectious but probably does not significantly alter the outcome of the disease. Immunization may reduce the symptoms of pertussis in those cases where it does not produce complete immunity. However, when the symptoms are not obvious, pertussis may be difficult to diagnose.