Burkholderia pseudomallei and Melioidosis in Mainland Southeast Asia: A Regional Synthesis of Ecological, Epidemiological, and Public Health Perspectives

Burkholderia pseudomallei ( B. pseudomallei ), the causative agent of melioidosis, is endemic to tropical and subtropical regions, particularly in Mainland Southeast Asia (MSEA). Despite its significant impact on human and animal health, the ecological distribution and public health burden of this environmental pathogen are still poorly documented. In MSEA, the bacterium is widespread, especially in rice–paddy irrigation water, canals, rivers, waterfalls, drinking‐water sources, and even in ornamental fish tanks. It has been detected at various soil depths, up to 3 m, and is commonly associated with specific soil types. Environmental factors, including the physicochemical properties of soil and water, strongly influence the distribution of B. pseudomallei . Natural disasters and extreme weather events such as flooding, tsunamis, and heavy rainfall can significantly increase the incidence of melioidosis in MSEA. Animal infections have been reported, including outbreaks in zoos and domestic animals across MSEA. Despite its public health impact, melioidosis remains a non‐notifiable disease in several MSEA countries, including Cambodia, Lao PDR, Myanmar, Peninsular Malaysia, and Vietnam. Treatment guidelines have been developed in several MSEA countries, although national guidance is absent or incomplete in Myanmar and is available only at the state level in Peninsular Malaysia. B. pseudomallei is widely distributed throughout the environment in MSEA, highlighting the need for integrated surveillance of environment, animal, and human infection. This narrative review aims to provide a comprehensive overview of the current knowledge on the ecology, epidemiology, and public health aspects of B. pseudomallei and melioidosis in MSEA, highlighting key knowledge gaps and priorities for surveillance, laboratory capacity, and cross‐border collaboration. Understanding the environmental distribution of B. pseudomallei and its links to climate and ecological factors is essential for anticipating changes in disease risk and implementing effective One Health strategies across MSEA.