Between 1 January 2024 and 24 August 2025, 71 confirmed cases of respiratory diphtheria, 2 probable respiratory diphtheria cases, and 2 cutaneous toxigenic diphtheria cases have been identified; as well as 52 asymptomatic carriers of toxigenic C. diphtheriae who were detected during contact tracing. The majority of confirmed and probable cases, together with carriers (70%, 89/127) were from the Western Cape, comprising 47 respiratory diphtheria cases, 1 cutaneous toxigenic diphtheria case, 1 probable respiratory case, and 40 asymptomatic carriers. The median age for cases of confirmed respiratory diphtheria was 25 years (range: 2–55 years), with 69% (49/71) aged ≥ 18 years. The overall case-fatality ratio (CFR) among probable and confirmed respiratory diphtheria cases was 21% (15/73). Among children and adolescents aged < 18 years, the CFR was 22% (5/23), compared to 20% (10/50) among adults.
Highlights:
- Since the last situational report (week 33), the following updates are included in this report:
- Two new laboratory-confirmed cases of toxigenic respiratory diphtheria, from the Western Cape.
- One new probable case of toxigenic respiratory diphtheria from the Western Cape.
- No new asymptomatic carriers of toxigenic C. diphtheriae.
- No new laboratory-confirmed cases of toxigenic cutaneous diphtheria.
- Appropriate public health responses have been initiated for all suspected and confirmed cases.
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.
