Melioidosis may not be a household name, but it’s a bacterial infection that warrants attention, particularly as environmental changes bring it closer to home in Australia. This disease, caused by the Burkholderia pseudomallei bacterium, typically lurks in soil and water in tropical and subtropical regions. However, as climate change continues to intensify, experts warn that melioidosis could start appearing in new regions across Australia. This is especially relevant now, as the Northern Territory’s wet season is underway, creating conditions that make transmission of the disease more likely.

While melioidosis can lead to severe complications if untreated, it’s not always easy to spot. The symptoms often resemble those of other common conditions, making melioidosis challenging to diagnose. For those in high-risk areas or with vulnerable health conditions, this is a crucial concern. 

That’s why we’ll break down everything you need to know about melioidosis—from how it spreads to what symptoms to watch for and steps you can take to reduce your risk. By understanding the nature of melioidosis, you’ll be better equipped to stay safe, especially during peak seasons and in areas where the disease is most common.

What is melioidosis?

Melioidosis, also known as Whitmore’s disease, is a bacterial infection caused by Burkholderia pseudomallei. This bacteria is naturally found in soil and water, particularly in tropical and subtropical regions such as Northern Australia and Southeast Asia. In these environments, it thrives in the wet season, when heavy rains and soil disturbances bring it closer to the surface, increasing the chances of human exposure.

While melioidosis might sound uncommon, its ability to cause severe, life-threatening illness makes it a disease worth understanding. This infection affects not only humans but also animals, and it can enter the body through inhalation, ingestion, or open wounds that come into contact with contaminated soil or water. For people with strong immune systems, melioidosis may present only mild symptoms or even remain dormant for years. In individuals with certain health vulnerabilities, however, the bacteria can become highly aggressive, leading to serious infections in the lungs, bloodstream, or multiple organs.

One of the complexities of melioidosis is its potential to mimic other illnesses. Its symptoms often overlap with those of pneumonia, tuberculosis, or septicemia, which can lead to misdiagnosis. This is why melioidosis is sometimes called "the great mimicker"—its symptoms vary widely and depend on the infection’s location within the body.

How is melioidosis spread?

Melioidosis spreads primarily through environmental contact, making it different from many other infectious diseases that are passed from person to person. 

Here are the main ways the bacterium can enter the body and cause infection:

1. Direct contact with contaminated soil or water

The most common way people contract melioidosis is through skin contact with contaminated soil or water, particularly if they have open cuts, sores, or abrasions.

Who’s at risk: Farmers, construction workers, and anyone regularly engaging in outdoor activities in endemic regions are especially vulnerable. Gardening or walking barefoot in these areas can also pose risks.

2. Inhalation of bacteria

During extreme weather events, such as heavy rains or strong winds, the bacteria can be stirred up into the air, making it possible to inhale it. This can lead to respiratory infections, especially if the bacteria enter the lungs.

Who’s at risk: People exposed to airborne bacteria during storms, floods, or heavy winds are at risk. Those with respiratory issues may be particularly susceptible if inhaled bacteria cause a pulmonary infection.

3. Ingestion of contaminated water

While less common, melioidosis can also spread through ingestion of contaminated water, particularly in areas where sanitation practices are limited.

Who’s at risk: People who drink or use untreated water from ponds, rivers, or wells are more likely to encounter the bacteria in this way. This route of infection can also be a risk in areas where flooding may cause water contamination.

4. Rare person-to-person transmission

While very rare, cases of melioidosis transmission between people have been documented, typically involving close contact with an infected individual’s bodily fluids. Other potential routes, like transmission through breast milk or sexual intercourse, have also been reported, though these cases are exceptionally uncommon.

Symptoms of melioidosis

Symptoms of melioidosis generally appear within 1 to 4 weeks after exposure, however, in some cases, signs of the infection have emerged months or even years later, long after the initial contact with the bacteria. The symptoms of melioidosis can be deceptively varied, often mimicking those of other illnesses. This diversity in symptoms makes it challenging to diagnose, especially in areas where melioidosis is less common.

Common symptoms of melioidosis

Generally, melioidosis presents itself through a mix of symptoms that may include fever, headache, muscle aches, and general malaise. The symptoms can look different depending on where the infection shows up in the body. Here are some of the most common ways melioidosis can appear, according to the CDC:

1. Pulmonary infection

When the bacteria infects the lungs, melioidosis can present as a pulmonary infection, often resembling pneumonia.

Symptoms: 

• Persistent cough
• Chest pain
• Shortness of breath
• Fever

This form of melioidosis is often mistaken for other respiratory infections, which can delay proper treatment.

2. Bloodstream infection

If the bacteria spreads into the bloodstream, it can lead to a severe, systemic infection that can escalate quickly.

Symptoms: 

• High fever
• Rapid breathing
• Abdominal discomfort
• Confusion
• Joint or muscle pain

This form is particularly dangerous, as it can cause septic shock, leading to a potentially life-threatening condition if untreated.

3. Localised infection

Melioidosis can also manifest as a localised infection, typically in a specific area of the body where the bacteria entered.

Symptoms: 

• Pain
• Swelling
• Redness

There would sometimes be a pus-filled lesion in the affected area. This is often observed in skin wounds or at sites where the bacteria first made contact. While a localised infection might seem minor, it can spread to other areas if not treated promptly.

4. Disseminated infection

In cases where the bacteria spread to multiple organs, melioidosis becomes a disseminated infection, causing widespread health issues.

Symptoms: 

• Weight loss 
• Abdominal pain
• Chest pain
• Headaches
• Abscesses in organs like the liver, spleen, or brain

Disseminated infection can be particularly complex to treat, as it affects multiple parts of the body simultaneously.

Recognising early signs

Since melioidosis symptoms can vary widely and appear similar to other illnesses, it’s essential to be vigilant, especially if you live in or have traveled to a region where melioidosis is present. Early signs often include fever, fatigue, and localised pain, which might not seem alarming at first. But if these symptoms stick around or get worse—especially after spending time in wet, muddy areas—it’s really important to get checked out by a doctor.

Diagnosis and treatment for melioidosis

Diagnosing melioidosis can be a complex process due to its diverse symptoms, which often mimic other conditions like pneumonia or tuberculosis.

Diagnosis of melioidosis

1. Medical history and symptom review

A doctor will begin by reviewing the patient’s symptoms, medical history, and recent travel or activity in areas where melioidosis is prevalent. Patients who have recently engaged in outdoor activities, such as farming or construction, may be at higher risk, particularly in regions with high levels of soil contamination.

2. Laboratory tests

• Blood and fluid cultures: The most definitive diagnostic method for melioidosis is culturing Burkholderia pseudomallei from blood, urine, or other bodily fluids. A positive culture confirms the infection and allows doctors to assess its severity.

• Imaging tests: In cases where the infection is suspected in specific organs, imaging tests like X-rays or CT scans may be used to detect abscesses or other signs of infection.

3. Serological tests

• Antibody detection: Serological tests that detect antibodies against the bacteria can help in diagnosing melioidosis, though they are often used alongside culture tests for a more accurate assessment.

Treatment for melioidosis

The treatment for melioidosis requires a structured approach due to the bacteria’s resilience. A two-phase antibiotic regimen is typically employed to tackle the infection effectively.

1. Intensive phase (Intravenous antibiotics)

Duration: 10 to 14 days

Medication: Patients usually receive intravenous antibiotics like ceftazidime or meropenem to control the initial infection. This phase is critical in tackling the acute symptoms and preventing the bacteria from spreading further in the body.

Hospitalisation: Most patients are hospitalised during this period to ensure close monitoring, as the infection can worsen rapidly without proper care.

2. Eradication phase (Oral antibiotics)

Duration: 3 to 6 months

Medication: Following the intensive phase, patients transition to oral antibiotics such as trimethoprim-sulfamethoxazole or doxycycline to eliminate any remaining bacteria and reduce the risk of relapse.

Follow-up: Regular follow-up appointments are essential to monitor progress and address any potential side effects of long-term antibiotic use.

Challenges in treatment

Melioidosis treatment poses unique challenges due to the bacteria’s ability to persist in the body, leading to relapses if not treated adequately. The need for an extended antibiotic course can be challenging for patients to complete, but strict adherence is crucial to prevent recurrence. In addition, antibiotic resistance is a growing concern, making it essential for healthcare providers to select the appropriate antibiotics carefully.

Preventing melioidosis

While there’s no vaccine for melioidosis, there are practical steps you can take to reduce your risk, especially in regions where the disease is more common. Here are some essential tips to help protect yourself:

1. Avoid direct contact with soil and standing water

When working outdoors, particularly during wet seasons, wear protective clothing, gloves, and closed footwear to avoid direct exposure to soil and water that may be contaminated.

Need the right safety gear? Explore our range of safety PPE to stay secure when working outdoors.

2. Practice good wound care

Ensure that any cuts, scrapes, or sores are properly cleaned and covered, especially if you’re spending time in areas where melioidosis is prevalent. The bacteria can enter the body through even minor skin breaks. Having a well-stocked first aid kit readily available is a smart precaution to quickly address any injuries, no matter where you are.

Shop first aid kits for home and workplaces.

3. Use safe drinking water

Avoid drinking untreated water in high-risk areas. Stick to boiled or bottled water to reduce the chance of ingesting the bacteria.

4. Limit outdoor activities during heavy rains

During monsoon or rainy seasons, when the bacteria may be more widespread, limit outdoor activities that involve direct soil or water contact.

5. Seek immediate medical attention

If you’ve had potential exposure and start experiencing symptoms such as fever, cough, or general malaise, consult a healthcare professional promptly. Early treatment can significantly improve recovery outcomes.

For additional ways to stay protected, check out our blog on essential products to have on hand to safeguard yourself from melioidosis.

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Health & Wellbeing Respiratory Health Seasonal Care