Diphtheria is caused by toxin-producing Corynebacterium diphtheriae (C. diphtheriae). This disease primarily manifests as respiratory infections that may result in death, but it may also present as mild infections in non-respiratory sites, such as the skin. While respiratory diphtheria is now extremely rare, non-respiratory infections caused by toxin-producing bacteria have recently been detected. Non-respiratory disease caused by toxin-producing C. diphtheriae may act as a source of transmission and can lead to new respiratory and non-respiratory diphtheria disease; both respiratory and non-respiratory disease caused by toxin-producing bacteria require public health follow-up. This diphtheria surveillance case definition better reflects the epidemiology of diphtheria in the U.S, in order to focus efforts on identifying disease caused by toxin-producing bacteria and appropriately guide public health interventions.
Confirmatory laboratory evidence:
Supportive laboratory evidence:
Epidemiologic linkage requires direct contact with a laboratory-confirmed case of diphtheria.
Individuals without evidence of clinical criteria as described by the diphtheria surveillance case definition but for whom toxin-producing Corynebacterium diphtheriae is confirmed via laboratory testing (isolation and toxigenicity testing by modified Elek test or other validated test capable of confirming toxin-production) should not be classified as cases. These individuals are considered carriers of the bacteria and are not reportable.