Causes and Transmission

Diphtheria is an infection caused by the Corynebacterium diphtheriae bacterium.

Diphtheria is spread (transmitted) from person to person, usually through respiratory droplets, like from coughing or sneezing. Rarely, people can get sick from touching open sores (skin lesions) or clothes that touched open sores of someone sick with diphtheria. A person also can get diphtheria by coming in contact with an object, like a toy, that has the bacteria that cause diphtheria on it.