The Northern Territory and Western Australia are experiencing outbreaks of an almost-eradicated infection, diphtheria.

The NT has recorded 17 cases of respiratory diphtheria in the past month and 60 cases of the less serious cutaneous diphtheria, affecting the skin, in the past year.

In the Kimberley region of WA, 27 cases have been reported in the past month alone, with one-quarter of those respiratory infections.

Cases have also been found in Queensland (two) and South Australia (one) this year.

Historically, diphtheria was a leading cause of childhood death globally. More than 4,000 Australians died from diphtheria between 1926 and 1935.

Vaccination started in Australia in the 1930s and the disease has rarely been seen since the 1950s.

But vaccine coverage has waned since the COVID pandemic, leading to a rising number of cases.

How do you contract it? And how does it progress?

Diphtheria is an infection caused by a toxin from the bacteria Corynebacterium diphtheriae or Corynebacterium ulcerans.

Infection occurs in the nose, throat and airway (respiratory diphtheria) or the skin (cutaneous diphtheria).

It spreads through respiratory droplets (coughs and sneezes) or direct contact with the fluid from infected skin sores.

Respiratory diphtheria presents with early symptoms of fever, sore throat, a general sense of feeling unwell (malaise) or loss of appetite.

Over the next few days, a greyish-white membrane may form over the throat and tonsils, making it difficult to swallow and breathe. It can progress to block the airway, causing death from asphyxia.

Cutaneous diphtheria presents as chronic skin ulcers that’s........

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