What is Whooping Cough and how does it spread?

By Rachael Lockhart

The History of Whooping Cough

Whooping cough was first mentioned in 1190. In 1674 Thomas Willis first described “chin-cough” as fierce fits of coughing until the organs used for breathing were in pain. He mentions that the blood must be stagnating and that they had blackness in their countenance suggesting a humoral approach to the understanding of what caused whooping cough with blood flow and most likely black bile leading to the coughing. In 1675 the disease was first noted as an epidemic in infants and children but it was not classified as fatal at that time. Many regions of Europe had their own name for whooping cough making it difficult to trace what they were referring to. With the lack of unified nomenclature for medical diseases, whooping cough could not, at that time, be shown to be present all over Europe. In 1701 whooping cough was first used to describe the cause of death in a report of the London Bills of Mortality. Throughout the beginning of the 18th century multiple physicians characterized whooping cough under different names. However, it wasn’t until the mid-18th century that attention was drawn to this highly infectious disease. At this time there was a lot of debate about what region of the body was primarily infected with the disease and it was also believed that only children could contract whooping cough. Robert Watt, after the death of two of his children, performed an autopsy to determine that the disease was directly attacking the respiratory tract of its victims in 1812-1813. During the 19th century the prevalence of whooping cough lessened. However, in 1922 the disease was noted in the United States. More recently, as vaccine rates have dropped a reemergence of whooping cough can be seen.

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Bordetella Pertussis under a microscope
Bordetella Pertussis

The causative agent of the disease, Bordetella pertussis, was isolated by Jules Bordet and Octave Gengou in 1900, but was unable to be grown in culture until 1906. Then in 1906 the characteristics of the bacteria and colony morphology were understood. After identifying the causative agent and determining how it causes disease, work began on developing a vaccine for whooping cough. By 1914 the first vaccine was invented in a combination product with tetanus and diphtheria and was known as DTP. After this the number of cases dropped substantially. However, the vaccine only lasted for 5-10 years. Because of the side effects of the vaccine, in the 1970s and 1980s, Sweden and Japan stopped the vaccination program for the pertussis vaccine due to safety concerns. Two outbreaks were traced back to this decrease in immunity from decreased vaccination rates in 1983 and 1985 in Sweden. Development of more effective vaccines with fewer side effects began. In the 1990s DTaP became a common vaccine readily available and replaced the last two doses of DTP given to children.

What Causes Whooping Cough and what are the symptoms?

In the 17th century Buchan and Burton classified the cause of whooping cough as an issue with excessive phlegm due to a blockage that prevented the normal excretion of the body’s poisons. They believed stomach needed to be cleaned out and strengthened and that the person should increase perspiration and other excretions. They also prescribed a change in air since it was due to the bad air that the blockage occurred. After the development of germ theory and the discovery of the causative agent for whooping cough it is now understood that whooping cough is caused by the bacteria Bordetella pertussis. This is a gram-negative, encapsulated bacteria that is non-motile and spherical in shape with pili. Some studies have demonstrated that these bacteria are able to produce surface slime to form a biofilm. Biofilms significantly increase the virulence of a bacterial cell because it is more difficult for the body and medications to break down this barrier in order to kill the cell. This bacteria is highly specialized for growth in the human body and thrives at temperatures near body temperature. As mentioned B. Pertussis is a respiratory pathogen and can be located in the epithelium of the bronchial trees in the lungs. The cells will produce toxins causing damage to the surrounding tissue leading to the characteristic coughing. If not able to infect a human host, since humans are the only known reservoirs, the cells will not be able to survive for long. Temperatures above 120°F, ultra violet light, and drying out cause the bacteria to die very quickly once it leaves the human body. The bacteria has a 7-10 day incubation period which then turns into the catarrhal stage, lasting for 1-2 weeks. During the catarrhal stage the disease is highly infectious but symptoms are not able to be discerned from that of another infection. These symptoms include sneezing, low grade fever, and coughing. Because of this, the spread of whooping cough is extremely difficult to prevent. The characteristic cough, which often is so violent it causes vomiting, develop during the next stage. This stage is called the paroxysmal stage and lasts 1-6 weeks. The whooping cough is observed in this stage. The final stage can last for several months and includes a prolonged cough, although non paroxysmal or whooping.

A public health announcement about the spread of Whooping cough demonstrating the spread of the disease through particles expelled during coughing or sneezing.
Public Health Advisory

The spread of Whooping Cough

In the 17th century and before it was believed that bad air was what caused Whooping cough. Although partially true since the bacteria is spread from person to person via airborne particles that are expelled from the lungs when an individual undergoes a coughing fit, this is not a full picture of what actually occurs. All the MOH understood that Whooping Cough is mostly found in children and is often most fatal in young children and infants. These reports mention then that the major places that whooping cough is spread is between school children and family members. Many studies have been conducted to determine where an infected individual got the disease from and they found that the main perpetrators are siblings and other family members. The disease is thought to have started in Northern Europe but can now be found worldwide, especially in unvaccinated regions. Before germ theory was really understood, people believed you could get any disease simply by being to close to someone who already has the disease. Whooping Cough was no different, so people all believed you caught the disease by being near someone who already had it. While this is mostly true it doesn’t take into account the requirement of a specific route of transfer, in our case small liquid particles expelled during coughing. Many parents began pulling their children from school to prevent them from catching the disease and tried to quarantine sick children.

References

  1. MOH Hackney 1899
  2. MOH London County Council 1923
  3. MOH East Ham 1952
  4. MOH Acton 1908
  5. MOH Tottenham 1912
  6. MOH Deptford 1914
  7. MOH Hampstead 1913
  8. MOH Barking 1947
  9. MOH Walthamstow 1903
  10. MOH Harrow 1955
  11. VIII.156 – Whooping Cough
  12. Sources of Infant Pertussis Infection in the United States
  13. Pertussis (Whooping Cough)
  14. Whooping Cough: A brief History to the 19th Century
  15. Pertussis: History of the Disease and Current Prevention Failure
  16. Pathogen Safety Data Sheets
  17. The Treatment of Whooping Cough in Eighteenth-Century England