In pertussis – colloquially called whooping cough – (synonyms: Bordetella pertussis infection; pertussis (whooping cough); tussis convulsiva; whooping cough; ICD-10 A37.-: Whooping cough) is an infectious disease caused primarily by the bacterium Bordetella pertussis, a gram-negative, toxin-producing, aerobic rod. However, the bacterium Bordetella parapertussis can also lead to a whooping cough-like clinical picture, although the course is usually milder and shorter in this case.
Humans are currently the only relevant pathogen reservoir for Bordetella pertussis. Bordetella parapertussis is also found in sheep.
Occurrence: Infection occurs worldwide, but most commonly in central Europe.
The so-called contagiousness index (synonyms: contagiousness index; infection index) was introduced to quantify the contagiousness mathematically. It indicates the probability of a non-immune person becoming infected after contact with a pathogen. The contagiousness index for pertussis is 0.8-0.9, meaning that 80-90 out of 100 unvaccinated persons will become infected after contact with a pertussis-infected person.Manifestation index: Approximately 60-80% of pertussis-infected persons become recognizably ill with pertussis.
Seasonal accumulation of the disease: Whooping cough occurs more frequently in autumn and winter.
The pathogen is transmitted (infection route) via droplets that are produced when coughing and sneezing and are absorbed by the other person via the mucous membranes of the nose, mouth and possibly the eye (droplet infection) or aerogenically (through droplet nuclei containing the pathogen (aerosols) in the exhaled air).
The incubation period (time from infection to onset of the disease) is 8-10 days (6-20 days are possible).
The disease is divided into three stages:
- Stage catarrhale – characterized by flu-like symptoms (cold, mild cough, no or moderate fever, weakness); usually lasts 1-2 weeks.
- Stage convulsivum – seizure-like cough attacks; usually lasts 4-6 weeks.
- Stage decrementi – in this stage, symptoms subside slowly over 6-10 weeks
Peak incidence: non-immune infants and young children; increasingly in adulthood (two-thirds of the cases of pertussis recorded in Germany now occur in people over 19 years of age).
The incidence (frequency of new cases) is up to 1% per year in infants and up to 0.5% per year in adolescents.
Infectivity (contagiousness) begins at the end of the incubation period, peaks within the first two weeks, and may persist for up to three weeks after the onset of stage convulsivum. With antibiotic administration, infectivity persists only up to five days after the start of therapy.
The disease does not lead to immunity.
Course and prognosis: In adolescents and adults, pertussis usually progresses as a prolonged cough. Only after several weeks does the disease slowly subside. In infants, the course is usually more severe. Apneas (breathing stops) can occur here, while the coughing fits are less severe. The disease is one of the most frequent infectious causes of death in newborns and young infants (frequency: 2/1,000).
Vaccination: vaccination against pertussis is available and recommended for infants and young children. However, even persons vaccinated against pertussis can be temporary carriers of bordetella after contact with the pathogen.
In Germany, direct or indirect detection of the pathogen is reportable by name under the Infection Protection Act (IfSG) if the evidence indicates acute infection.
