Pertussis (Whooping Cough)

Symptoms and Causative Agent

Pertussis, also known as whooping cough, is an extremely contagious disease caused by the Bordetella pertussis bacterium. These bacteria produce toxins that paralyze parts of respiratory cells, leading to inflammation in the respiratory tract.

The incubation period for pertussis is generally between 7-10 days, but can last more than a month. After symptoms first appear, the disease can take anywhere from weeks to months to fully run its course.

Initial symptoms include runny nose, sneezing, and a mild cough, which may seem like a typical cold. A mild fever also generally occurs. However, the cough slowly becomes more severe. Eventually, the patient experiences bouts of rapid coughing, followed by the “whooping” sound that gives the disease its common name as they try to inhale. While the coughing fit is occurring, the patient may turn blue.

While symptoms may be less severe for adults, pertussis can be extremely dangerous for infants and young children.

Between bouts of coughing, the person typically does not appear ill.

Transmission

The bacteria that cause pertussis are spread in the air in droplets created when a sick person coughs or sneezes. People nearby can become infected by breathing in the droplets. 

Although cases of pertussis have dropped dramatically in the United States since the introduction of the pertussis vaccine, the disease has caused widespread outbreaks in recent years. In 2012, nearly 50,000 cases of pertussis were reported in the United States, the most cases since 1955. Twenty pertussis deaths were reported in 2012. Fifteen of those deaths occurred in infants too young to have received the vaccine.

Pertussis remains also a major problem in the developing world. The World Health Organization estimates that pertussis caused 89,000 deaths worldwide in 2012.

The tendency of pertussis to be milder in adults, sometimes escaping diagnosis, further complicates disease transmission. The coughing associated with the disease may be mild enough in an adult case to be mistaken as a simple cold. The adult, however, will still be contagious and can easily spread the disease to infants too young to be vaccinated, or to individuals whose immunity has waned.

Treatment and Care

Treatment for pertussis is generally limited to supportive care. Antibiotics are sometimes used; however, this is primarily done to remove the Bordetella pertussis bacteria from an infected patient’s secretions, reducing her ability to infect others. Antibiotic treatment is unlikely to affect the course of the illness unless administered very early on.

Antibiotics may be given to individuals in contact with the patient to prevent infection.

Complications

Infants younger than six months are particularly at risk for complications and death from pertussis. Complications include pneumonia (bacterial or viral), seizures, ear infections, and dehydration, among others. In adults, rib fracture from coughing is also possible.

The most common of these complications in infants is B. pertussis pneumonia, which accompanies almost all deaths from pertussis.

Available Vaccines and Vaccination Campaigns

Immunization against pertussis is available for children via the combination DTaP (diphtheria, tetanus, and acellular pertussis) vaccine. The DTaP vaccination replaced the previously used DTP shot, which protected against the same three diseases, but used a whole-cell preparation in the pertussis component—that is, it contained inactivated, but complete, Bordetella pertussis bacteria. For the DTaP combination vaccine, the whole-cell preparation was removed; “aP” stands for “acellular pertussis.” This vaccine provides protection against the disease by using only pieces of the pertussis bacteria, which results in fewer side effects than the whole-cell preparation.

A similar combination vaccine called Tdap offers booster protection against tetanus, diphtheria, and pertussis for adolescents and adults in certain situations.

Sources

• Centers for Disease Control and Prevention. . (134 KB). Accessed 01/25/2018.
• CDC. . Epidemiology and Prevention of Vaccine-Preventable Diseases. Atkinson, W., Wolfe, S., Hamborsky, J., McIntyre, L. eds. 13th ed. Washington DC: Public Health Foundation, 2015. (730 KB). Accessed 01/25/2018.
• CDC. . Accessed 01/25/2018.
• CDC. . Accessed 01/25/2018.
• CDC. . Accessed 01/25/2018.
• Paddock, C.D., Sanden, G.N., Cherry, J.D., et. al. Pathology and pathogenesis of fatal Bordetella pertussis infection in infants. Clinical Infect Dis. 2008; 328-38.
• CDC.  (1997) Morbidity and Mortality Weekly Report, 46(RR-7);1-25. Accessed 01/25/2018.
• World Health Organization. . Immunization, Vaccines, and Biologicals. Accessed 01/25/2018.