Epidemiology of melioidosis in Australia and the Pacific region

Melioidosis was first described in Australia in sheep in 1949 and the following year in humans. Like most endemic countries, the incidence of melioidosis closely parallels the monsoonal wet season, with an annual incidence in the Top End of the Northern Territory of 16.5 cases per 100,000. However, case-clusters have been described, not only with extreme weather events such as floods and cyclones, but also with contaminated environmental foci. Localised temperate areas of endemicity are also described in Australia, with cases in southern Western Australia and in southeast Queensland. Sporadic cases of melioidosis have also been described in Papua New Guinea, Guam and Fiji. More recently, cases have also been reported in the Western Province in Papua New Guinea and in New Caledonia. Molecular studies suggest that isolates from Australia and the Pacific region are diverse, distinct from, and ancestral to, those in Thailand. Ongoing studies are stratifying risk based on soil sampling.