Melioidosis in the Torres Strait Islands, Australia: Exquisite Interplay between Pathogen, Host, and Environment

Abstract

Burkholderia pseudomallei, a bacterium that lives in the soil of the tropics, causes the disease melioidosis. This retrospective study investigated the temporospatial epidemiology of the 49 laboratory-confirmed melioidosis cases in the Torres Straits Islands of tropical Australia between 1997 and 2017. An identifiable risk factor for the disease was present in 43/49 (88%) cases and in 35/36 (97%) cases with complete clinical data. The mean incidence of melioidosis varied across the region, from 0/100,000 persons/year in the Eastern Island Cluster to 116.1/100,000 persons/year in the Near Western Island Cluster. An environmental suitability score for the growth of B. pseudomallei-constructed using the rainfall, vegetation, and soil type on each island-correlated with disease incidence (Spearman's rho 0.51; P = 0.035). Melioidosis is an opportunistic disease that occurs in patients with specific risk factors, but its incidence is also strongly influenced by environmental factors that favor the growth of the causative organism.