In the past diphtheria was a major cause of death among children. Thanks to widespread vaccination in Belgium since 1959, diphtheria has almost disappeared from our country. But the bacteria are still in circulation and vaccination is the only way to prevent diphtheria.
How is diphtheria spread?
Diphtheria caused by the bacterium C. diphtheriae is usually spread from person to person:
- by droplets from the upper respiratory tract (coughing, sneezing, speech)
- from direct contact with infected skin lesions (cutaneous diphtheria)
- more rarely by indirect contact (hands or objects contaminated with infected secretions).
Diphtheria caused by the bacterium C. ulcerans is usually transmitted from animals to humans (zoonosis):
- by consumption of unpasteurised cow’s milk products
- by contact with cattle (cows), horses and other animals
- sometimes by contact with pets (cats and dogs).
Diphtheria caused by the bacterium C. pseudotuberculosis is transmitted from animals to humans (zoonosis):
- by contact with goats
- by consumption of unpasteurised goat’s milk products.
DID YOU KNOW? You can be a carrier of the bacterium responsible for diphtheria without developing the disease. A healthy carrier can nonetheless be contagious and spread the bacterium, sometimes for months.
Cutaneous diphtheria caused by the bacterium C. diphtheriae is often imported.
Cutaneous diphtheria caused by the bacterium C. ulcerans is sometimes transmitted by animals and is affected by poor hygiene or a weakened health status.
Infected people are highly contagious during the 2 weeks following the onset of symptoms. The contagiousness decreases over time but may persist for several months in healthy carriers.
In temperate regions, diphtheria is more common during the colder months due to closer contacts in interior locations.
In tropical climates, where cutaneous diphtheria is more common, no seasonal influence has been observed.