Leaked Data Reveals Diphtheria Surge in the Northern Territory
A recent leak of data from the Northern Territory (NT) Health department has revealed a significant surge in diphtheria cases in the region, with the number of reported infections increasing sharply in the month leading up to a public health alert. The information, shared by the department on Thursday with service providers, provides the first public insight into when the outbreak began and which areas were most affected.
[Graph: Diphtheria numbers by location date]
According to the leaked document, a small number of diphtheria cases were recorded in the NT in early January. However, from the last week of February onwards, the number of cases began to rise steadily each week across Darwin, the Top End, and the Katherine region. Despite this growing trend, the NT Health did not issue a public health alert regarding the outbreak until March 25.
On Thursday of last week, Federal Health Minister Mark Butler stated that the Northern Territory government had sought assistance from the Commonwealth in late-April. This marks the worst diphtheria outbreak in Australia since records began in 1991.
NT Health’s Reluctance to Share Data
The ABC has previously requested a detailed breakdown of diphtheria cases by region from NT Health but received no response. In contrast, health departments in Western Australia and Queensland provide public online data on case numbers and locations. At a press conference on Tuesday, NT Chief Health Officer Dr Paul Burgess stated that the outbreak had spread throughout the entire territory but refused to provide specific details.
“It’s actually all over the five regions of the Northern Territory,” he said.
An NT Health spokesperson confirmed the authenticity of the leaked data but clarified that it was never meant for public release. The daily epi curve chart, part of a clinical briefing intended for healthcare professionals, was not designed for public distribution. “Changes may occur even daily as information comes to light for places of acquisition,” the statement read.
Despite this, the data seen by the ABC showed that the number of cases was often revised upward in subsequent reports. This suggests that earlier reports were conservative estimates of the true case numbers.
Vaccine Roll-Out and Public Response
NT Health has confirmed one death related to the diphtheria outbreak in the territory. In response to the rising case numbers, both the Territory and Federal governments have launched a large-scale vaccine roll-out.
The data indicates that aggregate case numbers have decreased over the past three weeks, aligning with statements from NT Health Minister Steve Edgington and the Chief Health Officer. “We have seen a reduction in the number of reported cases, and whilst we’re not out of the woods, it is important to recognize that reduction has continued,” Edgington said on Tuesday.
In addition, the Commonwealth announced a $7.2 million funding package to help mitigate the spread of diphtheria. Cases of the disease have also been reported in other parts of Australia.
National Diphtheria Outbreak Figures
On Friday, the Australian Centre for Disease Control (CDC) reported more than 260 cases of diphtheria nationwide in 2026. Of these, 159 cases were recorded in the Northern Territory, 102 in Western Australia, six in South Australia, and fewer than five in Queensland.
State health departments have provided slightly different figures. As of Friday, Western Australia reported 98 cases, South Australia reported seven, and Queensland reported three. On Tuesday, NT Health Minister Steve Edgington indicated that 163 cases had been identified in the NT, with 115 being cutaneous and 48 being respiratory.
