Increased Incidence of Melioidosis in Far North Queensland, Queensland, Australia, 1998–2019

B urkholderia pseudomallei, an environmental gram- negative bacterium, causes the disease melioidosis.Although infection is frequently asymptomatic, melioidosis may be rapidly fatal for patients with underlying conditions that increase the risk for invasive disease.Modeling suggests that B. pseudomallei is ubiquitous in the tropics and that the global burden of disease is expected to rise (1).Indeed, increased melioidosis incidence has been documented in some countries (2).Although this increase may be associated with improved diagnostic capacity, it may also be explained by a growing burden of predisposing concurrent medical conditions or by greater B. pseudomallei exposure from environmental disruption (3,4).Changing weather patterns also have the potential to increase melioidosis incidence (5).B. pseudomallei is endemic to Far North Queensland (FNQ), a region in the northernmost part of the state of Queensland, Australia (Figure 1).Incidence of melioidosis in the Torres Strait Islands in the region's north is among the highest reported in published series of melioidosis cases in Australia (4,6).During the past 20 years, the FNQ population has grown rapidly, predominantly in the city of Cairns, the region's major industrial hub, and in the nearby towns (Cairns area, in and around Cairns).This growth has necessitated substantial expansion of local infrastructure, including 2-phase development of a large motorway on the city's southern outskirts during 2011-2017.Surveillance data suggest that this development coincided with a marked increase in the local incidence of melioidosis, primarily in the Cairns area.We aimed to determine if there was any temporospatial association between the motorway construction and the increasing incidence of melioidosis in the region or if there were other possible explanations for any observed change, with a particular focus in the Cairns area. The StudyCairns Hospital is the sole public microbiological service provider for FNQ, a region of >380,000 km 2 (7).We reviewed all culture-confi rmed cases of B. pseudomallei infection identifi ed in the hospital's laboratory during January 1, 1998-December 31, 2019.Clinical details of each case were recorded as described by J.D. Stewart et al. (4); predisposing conditions were diabetes mellitus (glycated hemoglobin ≥6.5%), hazardous alcohol use, chronic lung disease, chronic renal disease, and immunosuppression.We used data from the Australian Bureau of Statistics to calculate disease incidence and from the Australian Bureau of Meteorology to record local climatic factors including rainfall, temperatures, cloud cover, dew points, and cyclones.For our analyses we used Stata version 14.2 statistical software (https://www.stata.com)and determined trends over time by using an extension of the Wilcoxon rank-sum test and using year of presentation as a continuous variable (8).We constructed maps by using MapInfo Pro 2019 Geographic Information System software Increased Incidence of Melioidosis in Far NorthQueensland, Queensland,