Commonly called whooping cough, pertussis is a highly contagious bacterial disease caused by Bordetella pertussis.
In some countries, this disease is called the ‘100 days cough’ or ‘cough of 100 days’.
Symptoms are initially mild, and then develop into severe coughing fits, which produce the namesake high–pitched “whoop” sound in infected babies and children when they inhale air after coughing. The coughing stage lasts approximately six weeks before subsiding.
Prevention by vaccination is of primary importance given the seriousness of the disease in children. Although treatment is of little direct benefit to the person infected, antibiotics are recommended because they shorten the duration of infectiousness. It is currently estimated that the disease annually affects 48.5 million people worldwide, resulting in nearly 295,000 deaths.
Signs and Symptoms
The classic symptoms of pertussis are a paroxysmal cough, respiratory whoop, fainting, and/or vomiting after coughing. The cough from pertussis has been documented to cause subconjunctival hemorrhages, rib fractures, urinary incontinence, hernias, post-cough fainting, and vertebral artery dissection. Violent coughing can cause the pleura to rupture, leading to a pneumothorax. If there is vomiting after a coughing spell or an inspiratory whooping sound on coughing, the likelihood almost doubles that the illness is pertussis. On the other hand, the absence of a paroxysmal cough or posttussive emesis makes it almost half as likely.
The incubation period is typically 7 to 10 days, with a range of 4 to 21 days. Rarely it may last up to 42 days, after which there are usually mild respiratory symptoms (mild coughing, sneezing, runny nose). This is known as the catarrhal stage. After one to two weeks, the coughing classically develops into uncontrollable fits, each with five to ten forceful coughs, followed by a high-pitched “whoop” sound in younger children, or a gasping sound in older children. This occurs as the patient struggles to take a breathe afterwards (paroxysmalstage).
Fits can occur on their own or can be triggered by yawning, stretching, laughing, eating, or yelling. They usually occur in groups, with multiple episodes every hour around the clock. This stage usually lasts two to eight weeks – sometimes longer. A gradual transition then occurs to the convalescent stage, which usually lasts one to two weeks. This stage is marked by a decrease in paroxysms of coughing, both in frequency and severity, and a cessation of vomiting. A tendency to produce the “whooping” sound after coughing may remain for a considerable period after the disease itself has cleared up.