Diphtheria is an infectious disease which is transmitted between people via saliva droplets which are ejected from a patient's throat when he/she coughs or sneezes. The incubation period is generally two to five days.
Diphtheria is generally localised to the tonsils, pharynx and larynx, although it can occasionally be found on the skin.
The symptoms range from mild sore throat to malignant diphtheritic laryngitis which can be fatal and which affects the larynx or the upper and lower respiratory tract. It is often complicated by myocarditis (entry of toxin into the cardiac muscle) and neuritis (entry of toxin into peripheral nerves).
Even if appropriate treatment is started, the disease is fatal in 5 to 10% of cases. Untreated, the mortality rate is higher still.
Untreated patients remain infectious for two to three weeks.
Treatment involves immediate administration of anti-diphtheria serum and antibiotics.
Antibiotic therapy abolishes infectiousness over 24 hours.
Unless vaccinated, children and adults can contract the disease several times.