Between 1 January 2024 and 13 April 2025, 43 confirmed cases of respiratory diphtheria, 1 probable respiratory diphtheria case and 40 asymptomatic carriers of toxigenic C. diphtheriae, detected during contact tracing, have been identified in South Africa. The majority of confirmed cases and carriers (80%, 66/83) were from the Western Cape, comprising 31 respiratory diphtheria cases and 35 asymptomatic carriers. The median age of cases of confirmed respiratory diphtheria was 28 years (range: 2–55 years), with 74% (32/43) being 18 years and older. The overall case-fatality ratio (CFR) among probable and confirmed respiratory diphtheria cases was 20% (9/44). Among children and adolescents under 18 years, the CFR was 18% (2/11), compared to 22% (7/32) among adults.
Highlights:
- Since the last situational report (week 14), the following updates are included in this report:
o Three new laboratory-confirmed cases of toxigenic respiratory diphtheria, one from Limpopo, one from Mpumalanga and one from the Western Cape
o Two new asymptomatic carriers of toxigenic C. diphtheriae, both from Limpopo - Appropriate public health responses have been initiated for each case
Information for clinicians
Clinical presentation of respiratory diphtheria
Respiratory diphtheria is a vaccine-preventable illness caused by toxigenic C. diphtheriae (and more rarely C. ulcerans or C. pseudotuberculosis), and can occur in persons of all ages.
The clinical presentation includes the following signs and symptoms:
- sore throat
- low-grade fever
- AND an adherent membrane of the nose, pharynx, tonsils, or larynx – the membrane is greyish-white and firmly adherent to the tissue
- AND/OR enlarged glands in the neck (bull neck)
- toxin-mediated systemic signs including myocarditis, polyneuropathy and renal damage
Patient management
Treatment includes antibiotics (azithromycin or penicillin) to clear the organism from the throat and prevent onward transmission, and diphtheria anti-toxin (DAT) to neutralise unbound toxin. The dosage of DAT is determined by the duration and severity of illness. Treatment, contact tracing and chemoprophylaxis should be started prior to laboratory confirmation. Early administration of DAT may be life-saving and should not be delayed in cases with a high index of suspicion. Supportive care is primarily aimed at airway management and includes providing oxygen, monitoring with electrocardiogram and intubation or performance of a tracheostomy if necessary.
To access previous diphtheria situational reports, click here.
