Diphtheria Makes a Comeback in Australia: What you need to know about symptoms and prevention

Diphtheria is a contagious bacterial infection that mainly affects the throat and nasal passages. The bacteria release a potent toxin that can form a thick, gray or brown coating in the throat, making breathing and swallowing difficult.

Post Published By: Sujata Biswal

Updated : 20 May 2026, 12:58 PM IST

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New Delhi: A disease once considered nearly eradicated is re-emerging in Australia. Health authorities have reported multiple cases of diphtheria in the Northern Territory and Western Australia, raising alarms about the potential spread of this serious bacterial infection.

What Is Diphtheria?
Diphtheria is a contagious bacterial infection that mainly affects the throat and nasal passages. The bacteria release a potent toxin that can form a thick, gray or brown coating in the throat, making breathing and swallowing difficult. If untreated, this toxin can enter the bloodstream, potentially damaging the heart, kidneys, and nerves.

Types of Diphtheria

• Respiratory (Classical) Diphtheria: The most common form, affecting the nose, throat, tonsils, or voice box.
• Cutaneous Diphtheria: More prevalent in tropical regions, it causes painful skin sores, blisters, or scaly rashes.

Recognizing the Symptoms
Symptoms typically appear 2–5 days after exposure, though the incubation period can range from 1 to 10 days.

• Respiratory Diphtheria: Severe sore throat, difficulty swallowing or breathing, mild fever, weakness, swollen neck lymph nodes, and a characteristic thick coating at the back of the throat.
• Cutaneous Diphtheria: Painful skin ulcers, sores, or discoloration around wounds.

Some individuals may show no symptoms at all, acting as asymptomatic carriers who can unknowingly spread the disease.

How Diphtheria Spreads
Diphtheria is highly contagious and can be transmitted through:

• Airborne droplets: From coughing, sneezing, or spitting.
• Direct contact: Touching sores or blisters of an infected person.
• Contaminated objects: Sharing clothing, utensils, or toys used by an infected individual.

Prevention Is Key
Vaccination remains the most effective protection against diphtheria. Children typically receive combination vaccines such as DTaP or DT at an early age, while older children and adults are given booster doses (Tdap or Td) to maintain immunity. Anyone exposed to an infected individual should seek immediate medical attention.

Health officials emphasize vigilance and immunization as crucial steps to prevent the resurgence of this dangerous disease.