Ninety-four cases of melioidosis have been reported to Queensland Health tor 2025 year to date (1 Jan – 23 February).
This is more than 3 times the number of cases for the same period in 2024. It exceeds the total number for 2024. There have been 12 deaths.
Most cases come from Cairns, Townsville and the hinterland (89%). All these areas have been affected by floods. Cairns and Townsville experienced extreme rain events over a few days between late January and the first few days of February.
The association between melioidosis outbreaks and weather events is well recognised.
What is Melioidosis?
Melioidosis is an infectious bacterial disease of humans and animals. The bacteria are found in soil and water. While the bacteria is usually deep in the soil, under the right conditions the bacteria can be pushed towards the surface.
The scientific name for the bacteria is Burkolderia pseudomallei.
How is transmitted to humans?
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.
It can be transmitted from person to person in rare instances.
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
What is the risk of Melioidosis for travellers?
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 international 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.
How can I reduce my exposure?
- Protect open wounds, cuts from soil and contaminated water. Irrigate contaminated wounds thoroughly with antiseptics before applying a waterproof dressing.
- Use 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 case fatality rate is about 10%. Early detection and treatment is the key to survival.
The incubation period varies from under a day to more than 3 weeks. The median period is 3-4 days.
Melioidosis is a notifiable disease on pathological diagnosis in the NT, Queensland and WA.
Melioidosis - A deadly history
- Melioidosis is closely related to the disease known as Glanders, a disease of horses (Burkholderia mallei) and is spread to humans by direct contact with the animal. It also infects donkeys, mules, dogs, cats, and goats. Those at risk include abattoir workers, veterinarians, laboratory workers and carers of animals.
- The name comes from the old French word glandres, meaning glands.
- During WW1, it was suspected that German agents infected Russian horses and mules on the front line. It has been seen as a possible biological weapon due to its high mortality rate in humans.
