Melioidosis is an uncommon bacterial infection of humans and animals. The disease-causing agent is Burkholderia pseudomallei, which occurs in the soil and water throughout southeast Asia, northern Australia, and the South Pacific. The disease is also seen sporadically in other temperate regions. Melioidosis outbreaks have coincided with heavy rainfall, flooding, major excavations, and disturbances in plumbing that result in contamination of water supplies.
Melioidosis has been diagnosed in many animals, including cats and humans. Cats may succumb to infection due to a weakened immune system. Infection is normally transmitted from the environment to an animal rather than from animal to animal. The most common routes of infection are via skin inoculation, contamination of wounds, ingestion of soil or contaminated carcasses, or inhalation.
Signs can vary widely, and infection without signs is common. Infection may be associated with single or multiple curd-like nodules or abscesses, which can be located in any organ. The organs most commonly affected include the lungs, spleen, liver, and lymph nodes. Fever, loss of appetite, or swollen lymph nodes may be noted. When the infection enters through the skin, it often develops at distant sites without evidence of active infection at the site of entry. Pneumonia is the most common form of the disease in both animals and humans. Lameness can occur. It is possible for an infection to lie dormant before becoming apparent. Death may result in animals with sudden and intense infections or when vital organs are affected.
Melioidosis is diagnosed with laboratory tests that identify the bacteria in lesions and discharges. Blood tests may also be used. It is possible that this disease involves suppression of the immune system, especially in cats, so your veterinarian may run tests for other underlying diseases. Treatment with antibiotics can be expensive and prolonged. Treatment protocols adopted for human infections are expected to have more success than the usual approach using conventional veterinary antibiotics. There is a risk that signs will return after treatment is discontinued. In areas where the disease-causing bacteria exist, prevention involves providing your pet with housing and sleeping areas that are not exposed to soil and providing clean drinking water that has been chlorinated and filtered (most municipal water supplies meet these requirements). Other preventive steps include restricting your pet’s access to the fecal material of other animals and to dead animals in the environment.
Melioidosis can be passed to people, so appropriate precautions should be taken when handling infected pets. The bacteria can be shed from wounds and, depending on the site of infection, from other sources, including nasal secretions, milk, feces, and urine.
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