Causes and Spread to Others

Young adult sneezing

Diphtheria bacteria usually spread from person to person through respiratory droplets, like from coughing or sneezing.

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

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.