Australia has seen more than 220 cases of diphtheria so far this year, the biggest outbreak of the disease since national records began in 1991.The Northern Territory has the largest number of positive cases at 133, followed by 82 in Western Australia, six in South Australia, and fewer than five in Queensland.In response to the outbreak, the federal and state governments have mobilized, and the Commonwealth is preparing a support package to bolster vaccination rates for a disease once considered almost eradicated, ABC News reported.Authorities are also waiting on the outcome of an investigation into a reported diphtheria-related death in the NT, which would be the first death from the disease in almost a decade.Federal health minister Mark Butler said the numbers were “very concerning.”“To put that in context, we've been recording case numbers nationally for about 35 years, and this, by a very big distance, is the biggest outbreak of diphtheria we've ever seen,” he said.The cases are rising amid falling vaccination rates on the continent. “I want to say this is not just very serious in terms of its numbers, but the vast majority of new cases we're seeing are respiratory diphtheria, which is far more serious in terms of its potential — about 25 per cent of cases are being hospitalized,” Butler said at a press conference on the NSW Central Coast.Also read: US Doctor With Ebola Admitted To Hospital In Germany2 Different Diphtheria Strains IdentifiedTwo strains of diphtheria have been identified in Australia: respiratory and cutaneous. While respiratory diphtheria can affect the nose, throat, and airways, cutaneous affects the skin, causing pus-filled blisters on the skin or large ulcers surrounded by red, sore-looking skin.The respiratory strain also spreads through droplets from coughing or sneezing, or direct contact with infected wounds. Even with treatment, one in 10 people with respiratory symptoms die, according to the Australian CDC.What Is Diphtheria? As per the World Health Organization (WHO), diphtheria is a disease caused by the Corynebacterium diphtheriae bacterium that affects the upper respiratory tract and, less often, the skin. It also produces a toxin that damages the heart and the nerves. While it is a vaccine-preventable disease, multiple doses are needed to produce and sustain immunity.Diphtheria has remained a leading cause of childhood death globally. But vaccination has long prevented mortality among children.Those who are not immunized remain at risk. WHO also mentions that diphtheria can be fatal in 30 per cent of cases, with young children at higher risk of dying if they are unvaccinated and are not receiving proper treatment.In 2023, an estimated 84 per cent of children worldwide received the recommended 3 doses of diphtheria-containing vaccine during infancy, leaving 16 per cent with no or incomplete coverage.According to Australia’s Department of Health and Aged Care, between 1926 and 1935, more than 4,000 Australians died from diphtheria. 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.Diphtheria: Signs And Symptoms Read More: UK Scientists Begin Drug Trial To Mend Broken Heart SyndromeWithin 2 to 5 days after exposure to the bacteria. The symptoms include a sore throat, fever,swollen neck glands, weakness. The dead tissue in the respiratory tracts forms a thick, grey coating that can cover tissues in the nose, tonsils, and throat, which makes it difficult to breathe and swallow. Severe cases happen as a result of the diphtheria toxin and its effects.Diphtheria: How the Disease Is Treated It is usually treated with diphtheria antitoxin as well as antibiotics. Antitoxin neutralizes the circulating toxin in the blood. Antibiotics stop bacterial replication and thereby toxin production, speed up getting rid of the bacteria, and prevent transmission to others. How To Prevent Diphtheria Diphtheria can be prevented by vaccines and routine immunization. The vaccine is given most often combined with vaccines for diseases such as tetanus, pertussis, Hemophilus influenzae, hepatitis B, and inactivated polio.