Melioidosis is an infectious disease caused by Burkholderia pseudomallei — a bacterium naturally found in tropical soil and water. It is endemic across Southeast Asia (Thailand, Vietnam, Cambodia, Malaysia), South Asia (India, Bangladesh, Sri Lanka) and Northern Australia, with emerging recognition in Africa and the Pacific. It causes pneumonia, septicaemia and localised abscesses — and is estimated to kill 89,000 people per year, yet receives almost no global health attention.

How common is melioidosis really?

A landmark 2016 Lancet Infectious Diseases modelling study (Limmathurotsakul et al.) estimated 165,000 annual cases and 89,000 deaths — making melioidosis as deadly as rabies, leptospirosis and many other tropical diseases that receive far more attention. However, most cases occur in countries with no laboratory capacity to culture B. pseudomallei — so almost none are confirmed. Countries with known high burden (Bangladesh, India) report near-zero cases officially.

Who gets melioidosis?

Risk factors: diabetes mellitus (present in approximately 50% of cases — the most important risk factor, increasing disease severity dramatically); chronic kidney disease; thalassaemia; hazardous alcohol use; and immunosuppression. Occupational exposure: farmers, agricultural workers and construction workers who work barefoot in soil and stagnant water. Healthy people without these risk factors rarely develop severe melioidosis.

What are the symptoms?

Melioidosis can present in many ways: acute pneumonia (most common — fever, cough, breathlessness resembling community-acquired pneumonia or TB); septicaemia (fever, shock, multi-organ failure — 20-40% of cases); localised infection (skin abscesses, liver/spleen abscesses, osteomyelitis, prostate abscesses). A truly multi-organ disease — it has been called "the great mimicker" alongside TB and syphilis.

How is melioidosis treated?

Intensive phase: IV ceftazidime (50mg/kg/dose every 6-8 hours) for minimum 10-14 days, or meropenem for severe disease. Eradication phase: oral TMP-SMX for 3-6 months to prevent relapse (which occurs in up to 10% of cases). Mortality remains approximately 20-40% in endemic settings even with treatment — reflecting the severity of the disease and comorbidities in those affected.

Why is melioidosis so underdiagnosed?

Three barriers: (1) Laboratory — blood cultures (required for diagnosis) must be kept for at least 5-7 days to grow B. pseudomallei, which is slower than most bacteria; most LMIC hospitals don't have this capacity. (2) Clinical awareness — melioidosis mimics so many other diseases (TB, typhoid, malaria, pneumonia) that clinicians don't consider it. (3) Biosafety — B. pseudomallei is a Category B bioterrorism agent; laboratories without proper biosafety may not handle it.

Is melioidosis a bioterrorism threat?

B. pseudomallei is classified as a Category B potential bioterrorism agent by the US CDC — because it can cause severe disease, is relatively environmentally stable and resistant to many antibiotics. The concern is that it could be aerosolised. However, its natural transmission is through soil and water contact — it is not transmitted person-to-person. The bioterrorism classification has unfortunately contributed to biosafety requirements that limit diagnostic capacity in endemic LMICs.

How does climate change affect melioidosis?

B. pseudomallei thrives in warm, moist conditions. Climate projections suggest warming and increased rainfall/flooding may expand its geographic range — with modelling suggesting parts of the Middle East, Central Asia and Africa may become endemic. Increased flooding (carrying B. pseudomallei from soil) and drought (concentrating bacteria in remaining water) may both increase exposure risk.

What research is being done?

A melioidosis vaccine is in early-stage development. Better rapid diagnostic tests (lateral flow assay for B. pseudomallei antigen) are being evaluated. Standardised treatment protocols are being developed for LMIC settings. The International Melioidosis Society (IMS) coordinates global research. WHO NTD listing has increased political commitment — but research investment remains minimal compared to the disease burden.

How does GMJ News cover melioidosis?

GMJ News covers WHO NTD melioidosis updates, Lancet ID burden estimates, diagnostic capacity development and climate change-melioidosis links. Melioidosis illustrates the broader NTD challenge of invisible diseases in the world's poorest populations — directly relevant to PHIG's global health equity advocacy.

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Melioidosis

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Melioidosis — caused by the soil and water bacterium Burkholderia pseudomallei — kills an estimated 89,000 people per year from approximately 165,000 annual cases, making it a deadlier neglected tropical disease than many better-known conditions including rabies and leptospirosis (WHO). Melioidosis is endemic across tropical Southeast Asia, South Asia and Northern Australia — where it lurks in soil and stagnant water, infecting through cuts, inhalation or ingestion, causing diverse presentations from pneumonia to septicaemia that mimic tuberculosis, typhoid and other conditions. Its true global burden is estimated to be 10 times higher than reported — driven by lack of diagnostic laboratory capacity in most endemic settings.

Key messages

89,000 deaths per year

Melioidosis kills an estimated 89,000 people per year from approximately 165,000 annual cases — a burden greater than rabies, leptospirosis or many better-known tropical diseases, yet it receives minimal global attention (Lancet Infectious Diseases 2016, WHO).

Burkholderia pseudomallei

Melioidosis is caused by Burkholderia pseudomallei — a Gram-negative bacterium found in soil and water across tropical Southeast Asia, South Asia and Northern Australia. It infects through skin contact, inhalation or ingestion.

Mimics many diseases

Melioidosis presents with diverse clinical syndromes — pneumonia, septicaemia, localised infection (skin, liver, prostate abscesses) — that mimic tuberculosis, typhoid and other common infections. This diagnostic confusion contributes to massive underreporting.

Massive underreporting

The true global burden of melioidosis is estimated to be 10-25 times higher than reported — because most cases occur in resource-limited settings without adequate laboratory capacity (blood culture, PCR) to confirm the diagnosis. Countries with highest burden often report zero cases.

WHO NTD listing 2018

Melioidosis was added to the WHO Neglected Tropical Diseases list in 2018 — recognising its enormous underappreciated burden and the need for increased attention to diagnostics, treatment access and research.

Ceftazidime treatment

Melioidosis is treated with an intensive phase of IV ceftazidime or meropenem (minimum 10-14 days), followed by oral trimethoprim-sulfamethoxazole (TMP-SMX) maintenance for 3-6 months to prevent relapse.

Key statistics

165K

estimated cases/year

Lancet ID 2016/WHO

89K

estimated deaths/year

Lancet ID 2016/WHO

45%

case fatality rate without treatment

WHO

10-25x

estimated underreporting factor

WHO/research

2018

year added to WHO NTD list

WHO

countries with confirmed melioidosis

WHO

Estimated melioidosis deaths per year by region — Lancet Infectious Diseases 2016

Source: Limmathurotsakul et al., Lancet ID 2016. SE Asia carries majority of burden.

Glossary of key terms

Burkholderia pseudomallei
WHOA Category B bioterrorism agent (CDC) and the environmental Gram-negative bacterium causing melioidosis. Found in soil and water in tropical environments. Highly intrinsically resistant to many antibiotics.

Septicaemic melioidosis
WHO/ClinicalThe most severe form — bacteraemia with widespread infection causing septic shock and multi-organ failure. Case fatality rate >50% even with treatment. Most common presentation in immunocompromised patients and those with diabetes.

Ceftazidime
WHO/IDSAThird-generation cephalosporin — the first-line intensive phase treatment for melioidosis. Given IV for minimum 10-14 days. Meropenem is an alternative for severe disease. High doses required due to the pharmacokinetics of B. pseudomallei.

TMP-SMX eradication therapy
WHOTrimethoprim-sulfamethoxazole (TMP-SMX) — taken orally for 3-6 months after the intensive phase — to prevent melioidosis relapse. Essential because B. pseudomallei can persist in tissues.

Risk factors
WHODiabetes mellitus (the strongest risk factor — present in approximately 50% of cases); chronic kidney disease; thalassaemia; heavy alcohol use; immunosuppression; occupational soil/water exposure (farmers, construction workers). Healthy people rarely develop severe disease.

Flagging wet season
WHO/researchMelioidosis cases surge dramatically during monsoon seasons — when flooding disperses B. pseudomallei from soil, increasing human exposure through skin contact with contaminated water and soil. Climate change may expand the geographic range of B. pseudomallei.