Causes of diphtheria 

Two types of bacteria can cause diphtheria.

They are:

  • Corynebacterium diphtheriae
  • Corynebacterium ulcerans

The bacteria spread when an infected person coughs or sneezes and droplets of their saliva enter another person's mouth or nose. The bacteria can be transferred by an infected person onto household items, such as cups, towels or cutlery.

Diphtheria is usually caught after being in close or prolonged contact with someone who has the condition or is carrying the infection. For example, you may catch diphtheria from someone you live with.

In countries where standards of hygiene are poor, diphtheria can often affect the skin (cutaneous diphtheria). In these cases, the bacterial infection is spread through contact with the infected wound rather than by breathing in infected droplets.

Infection from animals

You can become infected with Corynebacterium ulcerans after coming into close contact with cattle, because they carry the bacteria in their nose and throat.

You can also become infected with the bacteria after drinking unpasteurised milk or eating food made with unpasteurised milk.

Where diphtheria occurs

Diphtheria is rare in the UK, because the diphtheria vaccination is part of the routine childhood vaccination schedule.

However, diphtheria can be more common in parts of the world where fewer people are vaccinated, such as:

  • Africa
  • South Asia
  • the former Soviet Union

Page last reviewed: 16/02/2015

Next review due: 16/02/2017