Whooping cough, also known as pertussis, is a highly contagious respiratory infection caused by Bordetella pertussis bacteria. It leads to severe coughing fits that make breathing difficult and historically posed a serious threat, particularly to children. Understanding its origins and how its cause was identified highlights efforts to protect public health.
Early Recognition of the Illness
For centuries, whooping cough was recognized as a distinct illness due to its severe cough. Early descriptions of epidemics highlight the disease’s presence long before its microbial cause was understood. The first widely documented European epidemic occurred in Paris in 1578, detailed by French physician Guillaume de Baillou.
De Baillou’s observations described patients experiencing intense coughing that could lead to near strangulation and nosebleeds, primarily affecting children. Historical texts from earlier periods also suggest the disease’s presence, with mentions in Persian literature from 1501 and possible allusions in 14th-century Korea and 16th-century India. The term “pertussis,” derived from Latin meaning “intensive cough,” was introduced in 1670 by English physician Thomas Sydenham.
Identifying the Causative Agent
The scientific breakthrough in understanding whooping cough came in the early 20th century with the identification of its bacterial cause. Belgian scientists Jules Bordet and Octave Gengou were instrumental in this discovery. They first observed a small ovoid bacterium in the sputum of a five-month-old child with pertussis in Paris in 1900.
The crucial step of isolating and cultivating this bacterium was achieved by Bordet and Gengou in 1906. Their success was thanks to the development of a specialized culture medium, now known as Bordet-Gengou medium, which provided nutrients like blood, potato extract, and glycerol for the fastidious bacterium to grow. This bacterium was subsequently named Bordetella pertussis in honor of Jules Bordet.
The Significance of Discovery
The identification of Bordetella pertussis marked a significant moment in public health history. Pinpointing the specific causative agent allowed scientists to understand how the disease was transmitted, primarily through airborne respiratory droplets. This knowledge was fundamental for developing effective diagnostic tools, such as bacterial culture and later PCR tests, to confirm infections.
Most importantly, the discovery of the bacterium paved the way for vaccines. Bordet and Gengou themselves developed one of the first inactivated whole-cell vaccines in 1912, shortly after isolating the pathogen. Before widespread vaccine availability in the mid-20th century, whooping cough was a leading cause of childhood mortality, with hundreds of thousands of cases and thousands of deaths reported annually in countries like the United States. Identifying the pathogen enabled preventative measures that significantly reduced the incidence and severity of this illness.