Melioidosis in Asia: Hidden burden, epidemiological distribution, vaccine and therapeutic prospects, and public health priorities.

Melioidosis is an under-recognized tropical infectious disease caused by Burkholderia pseudomallei, an environmental pathogen that persists mainly in soil and surface water across tropical and subtropical regions. In Asia, the burden of melioidosis remains poorly defined because many cases are underdiagnosed, underreported, or clinically misclassified as tuberculosis, pneumonia, sepsis, or other bacterial infections. This narrative review examines the epidemiological distribution, transmission pathways, risk factors, vaccine and therapeutic developments, public health challenges, and future control strategies for melioidosis in Asia. Current evidence shows that Southeast Asia remains a major endemic region, while South Asia accounts for a substantial share of the modelled global burden of melioidosis. Reports from East Asia and other ecologically suitable areas suggest potential geographic expansion, particularly in relation to rainfall, flooding, extreme weather events, and climate change. Major risk factors include diabetes mellitus, chronic kidney disease, chronic lung disease, agricultural exposure, low socioeconomic status, and limited access to timely diagnosis and treatment. Although clinical management still depends on prolonged antimicrobial therapy, several vaccine candidates, including live-attenuated, recombinant, glycoconjugate, vesicle-based, and nanoparticle-based platforms, have shown protective effects in preclinical models. However, no licensed vaccine is currently available. Strengthening laboratory capacity, clinician awareness, notifiable disease surveillance, environmental monitoring, and integration with non-communicable disease programs is essential to improve detection and reduce mortality. An integrated One Health framework that links human, animal, and environmental health may support more effective surveillance, prevention, and control of melioidosis across Asia.