Surveillance

Although diphtheria is now rarely reported in the United States, the disease was one of the most common causes of illness and death among children before a vaccine was available. Since the introduction and widespread use of diphtheria vaccines, which began in the 1920s and 1930s, and universal childhood immunization in the late 1940s, diphtheria has been well-controlled in the United States.

Case Definition: For Health Professionals

The following case definition for diphtheria was revised by the Council of State and Territorial Epidemiologists and published in 2010.

Probable: In the absence of a more likely diagnosis, an upper respiratory tract illness with an adherent membrane of the nose, pharynx, tonsils, or larynx; and absence of laboratory confirmation; and lack of epidemiologic linkage to a laboratory-confirmed case of diphtheria.

Confirmed: An upper respiratory tract illness with an adherent membrane of the nose, pharynx, tonsils, or larynx; and any of the following: isolation of Corynebacterium diphtheriae from the nose or throat; or histopathologic diagnosis of diphtheria; or epidemiologic linkage to a laboratory-confirmed case of diphtheria.

Comment: Cutaneous diphtheria should not be reported. Respiratory disease caused by nontoxigenic C. diphtheriae should be reported as diphtheria. All diphtheria isolates, regardless of association with disease, should be sent to the Diphtheria Laboratory, National Center for Immunization and Respiratory Diseases (NCIRD), CDC.

Reporting to CDC

Suspected diphtheria cases should be reported promptly by telephone to the CDC Emergency Operations Center (770-488-7100) so that diphtheria antitoxin can be obtained for the patient. An FDA-licensed diphtheria antitoxin product is no longer available commercially in the United States. However, diphtheria antitoxin is available from CDC under an Investigational New Drug (IND) protocol. Additional epidemiologic and clinical data are needed as requirements to receive diphtheria antitoxin under the IND.

Healthcare professionals should notify their state health department promptly so that an epidemiologic investigation can be initiated. Reports of probable and confirmed cases should be forwarded by the state health department to the National Notifiable Disease Surveillance System. Reporting should not be delayed because of incomplete information or lack of laboratory confirmation.