Melioidosis is a significant and often overlooked infectious disease caused by the bacterium Burkholderia pseudomallei, primarily found in soil and water in endemic regions. It presents with a variety of symptoms and has a high case fatality rate, especially in Southeast Asia and Australia, with an estimated 250,000 annual deaths globally. The disease is challenging to diagnose and treat, necessitating improved awareness and healthcare responses in affected areas.

1. The Global Distribution and
Burden of Melioidosis
Direk Limmathurotsakul, MD MSc PhD
Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Thailand
Wellcome Trust Intermediate Fellow in Public Health and Tropical Medicine
Presented at 2nd GRF One Health Summit 2013, Davos

2. HAVE YOU EVER HEARD OF
THIS DISEASE ?

3. Melioidosis
• An infectious disease caused by Gram-
negative bacilli, Burkholderia pseudomallei
• Organism is present in soil and water in the
endemic areas
• Difficult to diagnose
• No specific clinical presentation.
• Common presentations include sepsis,
severe sepsis, septic shock, pneumonia,
and abscesses in any organs
• May present acute, sub-acute and chronic
• May mimic other diseases, such as TB

4. Melioidosis
• Diagnosis is made by culture positive for
the organism. No rapid tests are reliable.
So, microbiological facilities are needed.
• Even with such facilities, the organism may
be misidentified as “contaminant”,
“Pseudomonas spp” or other organisms
• Difficult to treat. General antibiotics such as
penicillin and gentamicin are not effective
• Highly fatal. Case Fatality rate is 60% in
Cambodia, 40% in Thailand and 14% in
Northern Australia
• Mostly died within 48 hours

5. Routes of infection
Inoculation
- B. ps is in soil
- High incidence in
farmers & aboriginals
- High incidence during
rainy season (working)
Inhalation
- Animal model
- Cases in helicopter
crew during Vietnam
Conflict
- More pneumonia
during rainy season
Ingestion
- B. ps is in water
- Outbreaks from
contamination in water
plants (twice in AUS)
- Acute parotitis in
children and adults

6. Melioidosis in animals
• Wide variety of animals are susceptible to
meliodosis, including horses, mules,
camels, sheep, lamb, cattle, goats, pigs,
kangaroos, koalas, alpacas, deer, cats,
dogs, rabbits, parrots, dolphins, pandas,
penguins and non-human primates
• Epizoonotic outbreaks from imported
animals from endemic areas
1957: sheep, goats and pigs on Aruba
1970: from Paris zoo to multiple cities in
France – sources could be due to infected
panda donated by Mao Tse-Tung

7. Interesting points
• Melioidosis is not contagious
• Melioidosis has zoonotic potential, but
it has been rarely reported.
• Both human and animals acquire the
diseases directly from the environment
• B. pseudomallei is classified as Tier 1
select agent by the US Federal Select
Agent Program (together with Bacillus
anthracis, Ebola virus, and the others)

8. HOW MANY ARE KILLED BY
MELIOIDOSIS EACH YEAR ?

9. Global distribution of B. pseudomallei
with level of evidence in each country
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Black, orange and yellow colors are for countries where the evidence is definite,
probable and possible, respectively
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10. Using environmental factors to predict
global distribution of B. pseudomallei
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Factors in the model: land surface temperature (in figure), rainfall, soil type, soil pH,
altitude, and vegetation index 50 5 x 5 kilometers resolution
at
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Methods was published in Bhatt et al, Nature (2013) Apr 25; 496(7446): 504-7
Latitude

11. Predicted probability of B. pseudomallei
in the environment
Red and orange colors represent areas where B. ps are likely to be present
Preliminary analysis estimated that population at risk is about 1.5 billion worldwide

12. Predicted mortality of melioidosis worldwide
Disease
Predicted
incidence
Predicted
mortality
Predicted case
fatality rate
Source of data
Tuberculosis
8,600,000
1,300,000
15%
WHO website
Malaria
219,000,000
660,000
0.3%
WHO website
2009 Pandemic
Influenza A H1N1
N/A
284,000
N/A
LID 2012,
12(9)687-695
Melioidosis
430,000
250,000
58%
Preliminary data
of this study
Severe Dengue
500,000
125,000
2.5%
WHO website
Leptospirosis
1,000,000
60,000
6%
ILS 2013

13. Predicted mortality of melioidosis worldwide
Country
Predicted
mortality
India
151,848
Bangladesh
36,320
Indonesia
10,049
Philippines
8,446
Myanmar
6,756
Nigeria
5,526
Vietnam
5,272
Thailand
3,173
Cambodia
2,357
Nepal
2,187
Pakistan
2,120
Ethiopia
1,538
etc..
..
List of countries where melioidosis
might be present but never reported
Africa: Ethiopia, Guinea, Cameroon,
Congo, Mozambique, Tanzania, Ghana,
Mali, Benin, Senegal, Liberia, Burundi,
Central African Republic, Somalia,
Sudan, South Sudan, Togo, GuineaBissau, Gabon, Comoros, Eritrea,
Rwanda,..
America: Guatemala, Nicaragua,
Paraguay, Trinidad and Tobago, Cuba,
Jamaica, Dominican Republic, French
Guiana
Asia: Nepal, Bhutan, ..

14. DO YOU NEED INFORMATION
ABOUT THIS DEADLY DISEASE ?

15. www.melioidosis.info

16. www.melioidosis.info

17. Conclusion
• Melioidosis is an important but overlooked infectious disease
• It is estimated that melioidosis kills 250,000 people per year,
and most are likely to be undiagnosed
• Further investigations need to be done in many tropical
countries
• Proper prevention, diagnosis and treatment should then be
provided to those areas

18. Acknowledgement
Nick Golding,
SEEG, Oxford
Eric Bertherat
WHO
David Dance,
LOMWRU, Laos
Prof Sharon Peacock,
Cambridge
Prof Nicholas Day
MORU, Thailand
Rungrueng Kitphati
Ministry of Public Health, Thailand
Prof Simon Hay
SEEG, Oxford

19. Increasing of incidence and emerging of
melioidosis worldwide !!!