The Northern Territory (NT) has the highest incidence of tuberculosis (TB) in Australia, but the rate of infection is decreasing, according to a collaborative study between the NT Centre for Disease Control, Menzies School of Health Research, and the Doherty Institute.

The study examined the genomic epidemiology of all confirmed cases of TB in the Territory’s Top End over three decades from 1989-2020.

One positive to come out of the study, was that the rate of TB in Aboriginal Territorians in the Top End has dropped by an average of five per cent per year.

Of the 739 people with TB, the study determined that 48 per cent were born overseas, 44 per cent were Aboriginal Australians, and seven per cent were Australian-born and non-Indigenous.

The study also found that Aboriginal people were more likely to die from TB (12%) than those residents born overseas (3%). 

Menzies PhD candidate and lead author Dr Ella Meumann said that combining patient epidemiological information with TB genomic sequencing has enabled better understanding of transmission clusters.

“Genetically linked cases mostly involved Aboriginal people in remote regions, with evidence that both recent transmission and reactivation of dormant TB after infection in the past, are contributing to TB cases in these areas.

“Genomic sequencing also found transmission links which had not been recognised during contact tracing. This approach therefore brings new insights into how TB is circulating in the NT,” Dr Meumann said.

NT Centre for Disease Control Director Dr Vicki Krause said the study also helps identify what can be done to decrease cases of TB in the NT.

“Eliminating tuberculosis is a global goal, and although Australia has one of the lowest incidences in the world it remains a public health challenge. This study helps us better understand how TB is transmitted in the Northern Territory,” Dr Krause said.

The study published in the LANCET Regional Health – Western Pacific is online here: Tuberculosis in Australia's tropical north: a population-based genomic epidemiological study