Melioidosis

Melioidosis is an infectious bacterial disease of humans and animals found in soil and water. The scientific name for the bacteria is Burkolderia pseudomallei.

Melioidosis is disease of tropical climates including Northern Australia, Southeast Asia, the Gulf Coast of Mississippi, Puerto Rico and the Virgin Islands. It is occasionally reported in Africa, the Middle East, and Central and South America. The distribution of the bacteria is likely underestimated,

Melioidosis often goes unrecognized in tropical and subtropical countries.

Cases are more likely to be reported at times of high rainfall and flooding (seasonal monsoons and post cyclones). The bacteria are usually deep in the soil but with the right conditions can be pushed towards the surface.

The disease is transmitted through direct contact with a contaminated source. This usually occurs through an open wound. Ingestion and inhalation are mentioned as other means of transmission, but these would be unusual.

In rare instances the bacteria can be transmitted from person to person.

Several medical conditions can increase the severity of the disease. These include:

• Liver disease
• Diabetes
• Cancers which may weaken the immune system.
• Chronic lung disease
• Kidney disease
• Blood disorders like Thalassemia

There isn’t currently a vaccine against Melioidosis. Prevention should focus on protective measures aimed at reducing exposure.

Most travellers have limited risk of exposure. The risk would be higher in those adventuring off the beaten path during the wet season or during periods of flooding.

In a recent study (2023) of travel associated melioidosis several findings were noted:

• Most occurred in males (71%)
• Asia was the most common destination identified (77%)
• The most frequent co-morbidity was diabetes (25%)
• Many had no risk factors (often young and healthy)
• The most common clinical presentation was pneumonia (35%) followed by sepsis (30%) and skin infection (14%).
• The disease was often identified within a week of returning home (55%) but almost a third had a delayed presentation of over 3 months.

• Protect open wounds, cuts from soil and contaminated water. Irrigate contaminated wounds thoroughly with antiseptics before applying a waterproof dressing.
• Using appropriate footwear when wading through soil contaminated water, particularly during the monsoons or after cyclones when there is considerable environmental contamination.
• Using waterproof gloves if undertaking agricultural work in a risk environment
• Adhere to the rules of eating and drinking safely in a contaminated environment (using boiled, bottled or treated water and avoiding uncooked raw foods).

Travellers who have visited areas of risk should respond quickly to symptoms which might suggest exposure. Unfortunately, symptoms can be non-specific and only suspected after a good history of possible exposure is provided.

The incubation period varies from under a day to more than 3 weeks. The median period is 3-4 days.