Causes and How It Spreads


Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make a toxin. It is the toxin that can cause people to get very sick.

Spread to others

Diphtheria bacteria spread from person to person, usually through respiratory droplets, like from coughing or sneezing. People can also get sick from touching infected open sores or ulcers. Those at increased risk of getting sick include:

  • People in the same household
  • People with a history of frequent, close contact with the patient
  • People directly exposed to secretions from the suspected infection site (e.g., mouth, skin) of the patient