Summary about Disease
Whitmore's disease, also known as melioidosis, is an infectious disease caused by the bacterium Burkholderia pseudomallei. It is found in soil and water, particularly in Southeast Asia and northern Australia, but can occur elsewhere. Infection can occur through contact with contaminated soil or water, inhalation of contaminated dust, or ingestion of contaminated water. The disease can manifest in a variety of ways, ranging from localized infections to severe pneumonia and septicemia (blood poisoning). It can be fatal, especially if left untreated.
Symptoms
Symptoms of melioidosis vary widely depending on the site of infection and can include:
Localized Infection: Pain, swelling, ulceration, abscess formation at the site of entry (skin).
Pneumonia: Cough, chest pain, fever, headache, respiratory distress.
Disseminated Infection: Fever, weight loss, stomach or chest pain, muscle or joint pain, headache, seizures, brain damage.
Septicemia (Blood poisoning): Fever, headache, respiratory distress, abdominal discomfort, joint pain, disorientation.
Other possible infections: Liver, spleen, prostate, kidney or brain
Causes
Melioidosis is caused by the bacterium Burkholderia pseudomallei. The bacteria are typically found in:
Contaminated soil
Contaminated water (especially surface water) Infection occurs through:
Direct contact: Contact with contaminated soil or water, often through skin abrasions or wounds.
Inhalation: Inhaling dust particles carrying the bacteria.
Ingestion: Drinking contaminated water. Person-to-person transmission is very rare.
Medicine Used
Treatment for melioidosis typically involves a two-phase approach:
Intensive Intravenous Therapy: Usually lasts 10-14 days, using antibiotics such as ceftazidime or meropenem.
Eradication Therapy: This phase involves oral antibiotics, most commonly trimethoprim-sulfamethoxazole (TMP-SMX), for 3-6 months to prevent relapse. Doxycycline, Amoxicillin-Clavulanate are alternatives. The specific antibiotics and duration of treatment depend on the severity and location of the infection and the patient's overall health.
Is Communicable
Person-to-person transmission of melioidosis is extremely rare. It is not considered a communicable disease in the traditional sense. Transmission is almost always environmental, from contact with contaminated soil or water.
Precautions
Precautions to minimize the risk of melioidosis infection include:
Avoid contact with soil and water: If possible, avoid contact with soil and stagnant water, particularly in endemic areas.
Wear protective clothing: Wear gloves and boots when working with soil or water, especially if you have cuts or abrasions.
Wash thoroughly: Wash hands and any exposed skin thoroughly with soap and water after contact with soil or water.
Avoid consuming untreated water: Drink only treated or boiled water in endemic areas.
Protect wounds: Keep any cuts, scratches, or burns clean and covered with waterproof bandages.
Occupational Safety: Workers in agricultural or construction fields should use respiratory protection and appropriate clothing.
How long does an outbreak last?
The duration of a melioidosis outbreak depends on the source of contamination and the effectiveness of control measures. If a localized source of contamination is identified and contained, the outbreak may be relatively short-lived (weeks to months). However, if the source is widespread or difficult to control, the outbreak may persist for longer periods (months to years) with sporadic cases. The length of the period with symptoms for an infected individual will vary based on the speed of diagnosis, treatment and overall health.
How is it diagnosed?
Diagnosis of melioidosis typically involves:
Culture: Isolation of Burkholderia pseudomallei from blood, sputum, urine, wound swabs, or other clinical specimens. This is the gold standard.
Serology: Antibody detection tests (e.g., indirect hemagglutination assay or ELISA) can support the diagnosis, particularly in areas where the disease is not common. However, these tests can have limitations due to cross-reactivity and prior exposure.
PCR (Polymerase Chain Reaction): Molecular tests can detect the bacterial DNA in clinical samples and provide a faster diagnosis than culture.
Imaging: Chest X-rays or CT scans to identify pneumonia or abscesses.
Clinical Presentation: Correlation of symptoms with risk factors (e.g., exposure to soil/water in endemic areas) is important.
Timeline of Symptoms
The incubation period for melioidosis can range from 1 to 21 days, but can be longer, even years in rare cases. The specific timeline of symptoms depends on the type of infection:
Acute Onset: Some patients develop symptoms rapidly within a few days after exposure.
Subacute Onset: Others experience a more gradual onset of symptoms over several weeks.
Latent Infection: In rare cases, the infection can remain dormant for months or years and then reactivate later. The progression of symptoms can also vary depending on the site of infection (localized, pneumonia, disseminated, septicemia).
Important Considerations
Endemic Areas: Melioidosis is primarily a disease of tropical regions, particularly Southeast Asia and northern Australia. Travelers to these areas should be aware of the risks.
Risk Factors: Individuals with diabetes, chronic kidney disease, chronic lung disease, weakened immune systems, alcohol abuse or other underlying health conditions are at higher risk of developing melioidosis.
Misdiagnosis: Melioidosis can mimic other diseases, leading to delayed diagnosis and treatment.
Relapse: Even with appropriate treatment, relapse can occur, highlighting the importance of long-term follow-up and adherence to eradication therapy.
Antimicrobial Resistance: Burkholderia pseudomallei can exhibit resistance to certain antibiotics, requiring careful selection of appropriate treatment regimens.
Reporting: Melioidosis is a reportable disease in many countries, and reporting is important for surveillance and public health efforts.