An atlas of common Salmonella serotypes from routinely notified human cases in the Northern Territory of Australia, 2005-2024.

Salmonella infections cost Australian society an estimated 140 million Australian Dollars (AUD) per year circa 2019. Salmonellosis is caused by Salmonella enterica, with over 2,500 serotypes of S. enterica identified. Knowledge of the epidemiology of Salmonella serotypes may facilitate traceback from strains detected in human cases to identify the cause of local and multijurisdictional outbreaks and to implement control measures. We analysed cases of human salmonellosis notified in the Northern Territory (NT), Australia, between 1 January 2005 and 31 December 2024. We calculated the incidence of salmonellosis for all locally acquired infections according to the NT location where the infection was most likely acquired. We mapped the geographical distribution of the 25 most frequently notified Salmonella serotypes to Statistical Areas Level 2. There were 8,706 salmonellosis cases acquired in the NT: Salmonella Saintpaul (1,047 notifications) was the most frequently notified serotype, followed by S. Virchow (948 notifications); S. Typhimurium (822 notifications); S. Ball (578 notifications); and S. Lansing (460 notifications). While S. Typhimurium was ubiquitous in the NT, S. Saintpaul, S. Virchow and S. Hvittingfoss showed distinct geographic patterns. Our atlas makes key epidemiological information about common NT Salmonella serotypes readily available, which may be useful for developing hypotheses during outbreak investigations; for facilitating traceback of suspected food vehicles; and for implementing control strategies more rapidly.