What is it?
Diphtheria is a highly contagious bacterial infection that is transmitted between humans and causes an infection of the upper respiratory tract, which can lead to breathing difficulties and asphyxiation. Diphtheria has caused devastating epidemics in the world throughout history and at the end of the nineteenth century; the disease was still the leading cause of infant mortality in France. It is no longer endemic in industrialized countries where the extremely rare cases observed are imported. However, the disease is still a health problem in areas of the world where childhood immunization is not routine. More than 7,000 cases were reported to WHOM worldwide in 2014.
Symptoms of Diphtheria
Respiratory diphtheria and cutaneous diphtheria are distinguished.
After an incubation period of two to five days, the disease is manifested by angina: throat irritation, fever, swollen neck glands. The disease is recognized by the formation of whitish or grayish membranes in the throat and sometimes the nose, causing difficulty in swallowing and breathing (in Greek, “diphtheria” means “membrane”).
In the case of cutaneous diphtheria, mainly in the tropics, these membranes are found at the level of a wound.
The origins of the disease
Diphtheria is caused by a bacterium, Corynebacterium diphtheriae, which attacks the tissues of the throat. It produces a toxin that causes the accumulation of dead tissue (false membranes) that can even obstruct the airways. This toxin can also spread in the blood and cause damage to the heart, kidneys and nervous system.
Two other species of bacteria are capable of producing diphtheria toxin and thus causing the disease: Corynebacterium ulcerans and Corynebacterium pseudotuberculosis.
Risk factors for Diphtheria
Respiratory diphtheria is transmitted from person to person by droplets sprayed during coughing and sneezing. The bacteria then enter the nose and mouth. Cutaneous diphtheria, which is observed in some tropical areas, is transmitted by direct contact with a wound.
It should be noted that, unlike Corynebacterium diphtheriae, which is transmitted from person to person, the other two bacteria responsible for diphtheria are transmitted from animals to humans (they are zoonoses):
- Corynebacterium ulcerans is transmitted by ingestion of raw milk or by contact with cattle and pets.
- Corynebacterium pseudotuberculosis, the rarest, is transmitted by contact with goats.
In our latitudes, it is in winter that diphtheria is the most frequent, but in tropical zone it is observed throughout the year. Outbreaks are more likely to affect densely populated areas.
Prevention and treatment of Diphtheria
Vaccination for children is mandatory. The World Health Organization recommends that the vaccine be given in combination with tetanus and whooping cough (DPT) at 6, 10 and 14 weeks of age, followed by booster injections every 10 years. Vaccination prevents 2 million to 3 million deaths worldwide from diphtheria, tetanus, whooping cough and measles, according to WHO estimates.
The treatment consists of administering as quickly as possible an anti-diphtheria serum to stop the action of the toxins produced by the bacteria. It is accompanied by antibiotic treatment to kill bacteria. The patient may be placed in respiratory isolation for a few days to avoid contagion with those around him. About 10% of people with diphtheria die, even with treatment, warn WHO.