Diphtheria Outbreak Declared in Northern Territory
The Northern Territory Department of Health has declared a diphtheria outbreak after confirming four cases of respiratory diphtheria within the last week. Three cases were identified in Darwin and one in Alice Springs. Additionally, 33 cases of cutaneous diphtheria have been reported since 2025.
Outbreak Details and Official Response
The declaration followed a public health alert issued by NT Health's Centre for Disease Control (CDC) on Wednesday. NT Health Chief Health Officer Paul Burgess commented on the unusual nature of the outbreak, noting that the territory has not experienced a similar event in 26 years.
"Control measures are in place, and the risk to the general public is considered low," stated Dr. Burgess.
Contact tracing efforts are currently underway to identify individuals who may have been exposed to the confirmed diphtheria cases.
About Diphtheria
Diphtheria is an infectious disease caused by toxic strains of the bacterium Corynebacterium diphtheriae. It is a vaccine-preventable illness. Transmission primarily occurs person-to-person through the inhalation of respiratory droplets. Less frequently, it can spread via direct skin contact with lesions from infected individuals.
Two main strains have been identified in the Northern Territory: respiratory and cutaneous. The most severe infections are a result of a toxin produced by specific strains of the bacteria.
Clinical Manifestations
Respiratory Diphtheria
This form can be life-threatening if left untreated. Symptoms may include a sore throat, mild fever, loss of appetite, and in severe instances, difficulty breathing. A grey pseudomembrane may cover the tonsils and mucosa of the pharynx, larynx, and nose. Enlarged anterior cervical lymph nodes and soft tissue oedema can also occur, potentially leading to a characteristic ‘bull-neck’ appearance.
Cutaneous Diphtheria
This form typically presents as chronic, non-healing sores or shallow ulcers, often located on the legs. These lesions may also feature a grey membrane.
Prevention and Vaccination
Vaccination provides effective protection against diphtheria by stimulating the production of antibodies to the diphtheria toxin. Authorities recommend that individuals verify their vaccination status and ensure they and their children are vaccinated.
The diphtheria vaccine is available in Australia as a combination vaccine, also providing protection against pertussis (whooping cough) and tetanus.
Recommended Vaccination Schedule
The diphtheria vaccine is provided free of charge for children at the following ages:
- Six weeks
- Two months
- Four months
- Six months
- 18 months
- Four years
- 12 years
Adults are recommended to receive a booster vaccination every 10 years. Pregnant women are advised to get vaccinated between 20 and 32 weeks of pregnancy. Children, adolescents, and adults are encouraged to ensure their DTPa or dTpa vaccinations are current.