Melioidosis

Other Names: Burkholderia pseudomallei infection; B pseudomallei infection; Whitmore disease; Nightcliff gardener's disease

Melioidosis, also called Whitmore’s disease, is an infectious disease that can infect humans or animals. The disease is caused by the bacterium Burkholderia pseudomallei.

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Epidemiology

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While melioidosis infection has taken place all over the world, Southeast Asia and northern Australia are the areas in which it is primarily found. In the United States, confirmed cases reported in previous years have ranged from zero to five and have occurred among travelers and immigrants coming from places where the disease is widespread. Moreover, it has been found among troops of all nationalities that have served in areas with widespread disease. The greatest numbers of melioidosis cases are reported in:

• Thailand
• Malaysia
• Singapore
• Northern Australia

Transmission

People can get Melioidosis through direct contact with contaminated soil and surface waters. Humans and animals are believed to acquire the infection by inhalation of contaminated dust or water droplets, ingestion of contaminated water, and contact with contaminated soil, especially through skin abrasions. It is very rare for people to get the disease from another person. While a few cases have been documented, contaminated soil and surface water remain the primary way in which people become infected.

Riskfactors

Although healthy people may get melioidosis, the major risk factors are:

• Diabetes
• Liver disease
• Renal disease
• Thalassemia
• Cancer or another immune-suppressing condition not related to HIV
• Chronic Lung disease (such as cystic fibrosis, chronic obstructive pulmonary disease (COPD), and bronchiectasis)

Infection Classifications

Melioidosis can be categorized as an acute or localized infection, acute pulmonary infection, acute bloodstream infection, or disseminated infection.

• Localized Infection
• Pulmonary Infection
• Bloodstream Infection
• Disseminated Infection

Signs and Symptoms

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There are several types of melioidosis infection, each with their own set of symptoms. However, it is important to note that melioidosis has a wide range of signs and symptoms that can be mistaken for other diseases such as tuberculosis or more common forms of pneumonia.

Localized Infection: Localized pain or swelling

• Fever
• Ulceration
• Abscess

Pulmonary Infection:

• Cough
• Chest pain
• High fever
• Headache
• Anorexia

Bloodstream Infection:

• Fever
• Headache
• Respiratory distress
• Abdominal discomfort
• Joint pain
• Disorientation

Disseminated Infection:

• Fever
• Weight loss
• Stomach or chest pain
• Muscle or joint pain
• Headache
• Seizures

The time between an exposure to the bacteria that causes the disease and the emergence of symptoms is not clearly defined, but may range from one day to many years; generally symptoms appear two to four weeks after exposure.

Diagnosis

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Melioidosis is diagnosed by isolating Burkholderia pseudomallei from blood, urine, sputum, skin lesions, or abscesses; or by detecting an antibody response to the bacteria.

Treatment

When a melioidosis infection is diagnosed, the disease can be treated with the use of appropriate medication. The type of infection and the course of treatment will impact long-term outcome. Treatment generally starts with intravenous (within a vein) antimicrobial therapy for 10-14 days, followed by 3-6 months of oral antimicrobial therapy. Antimicrobial agents that have been effective against melioidosis include:

Intravenous therapy consists of:

• Ceftazidime administered every 6-8 hours or
• Meropenem administered every 8 hours

Oral antimicrobial therapy consists of:

• Trimethoprim-sulfamethoxazole taken every 12 hours or
• Amoxicillin/clavulanic acid (co-amoxiclav) taken every 8 hours

Patients with penicillin allergies should notify their doctor, who can prescribe an alternative treatment course.

Prevention

In areas where the disease is widespread, contact with contaminated soil or water can put people at risk for melioidosis. However, in these areas, there are things that certain groups of people can do to help minimize the risk of exposure: Persons with open skin wounds and those with diabetes or chronic renal disease are at increased risk for melioidosis and should avoid contact with soil and standing water. Those who perform agricultural work should wear boots, which can prevent infection through the feet and lower legs. Health care workers can use standard precautions when treating patients with melioidosis to help prevent infection.

NIH genetic and rare disease info

• NIH info on Melioidosis

Melioidosis is a rare disease.

Melioidosis Resources
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