Melioidosis is an emerging infectious disease in Brazil, the etiological agent of which is Burkholderia pseudomallei, found in contaminated soil and water. The disease occurs predominantly in tropical regions, particularly in Thailand and Australia, where it is a major health problem. People and animals can get the infection through environmental contact with soil and water. The disease is little known in Brazil and manifests itself in a similar way to many infectious diseases, which makes its diagnosis difficult. Thus, attention to its early diagnosis and treatment is important.
The disease occurs predominantly in Southeast Asia and Northern Australia. The countries where the disease is most prevalent are Thailand, Australia, Malaysia and Singapore. The distribution of melioidosis has been described in the Asian region as Vietnam, Cambodia, Laos, subcontinental India, as well as in other continents such as Papua New Guinea in Oceania, Africa, Central America and South America. In Brazil, the first cases occurred in Ceará in 2003 and since then the State has been detecting the disease and alerting to the detection of the disease in other regions of the country. In addition to Ceará, there is a record of the disease in Mato Grosso and Alagoas.
Transmission may occur by inhalation of contaminated water or dust particles, ingestion or aspiration of contaminated water, inoculation into skin and mucous membranes, particularly on non-intact skin.
Person-to-person transmission is extremely rare with few cases described (sexual and vertical transmission).
Laboratory transmission, although rare, may also occur.
The incubation period is variable. Australian study showed incubation period from 1 to 21 days with a mean of 9 days. In acute cases the incubation period is usually short, and may be only 2 to 3 days. The disease may remain dormant for long periods and has been described for up to 62 years after exposure.
Anyone can get the infection, but melioidosis is more common in people with pre-existing conditions such as diabetes, chronic kidney disease, chronic lung disease, chronic liver disease, or people who take therapy with corticosteroids or immunosuppressive drugs or are alcoholics.
The disease is considered a "spectacular mimic" because it can present multiple clinical forms and be confused with other infections. The main clinical presentations of the disease are:
- Asymptomatic infection
- Localized infection with skin and soft tissue infection.
- Pulmonary infection - Acute infection leads to severe pneumonia.
- Symptoms include high fever, cough, chest pain, muscle pain and headache.
- Severe acute infection can progress rapidly with shortness of breath and respiratory failure.
- Chronic lung infection is similar to tuberculosis with prolonged fever, cough and weight loss.
- Bloodstream infection ("septicemia") - Symptoms generally include high fever, headache, restlessness, disorientation, shortness of breath, and drop in blood pressure.
- Chronic infection - any organ or part of the body can be infected and thus the symptoms are usually quite varied. Infections can occur in the joints, lymph nodes, abscesses at various sites such as the liver, spleen, brain and prostate.
The diagnosis is laboratorial and performed through the isolation of Burkholderia pseudomallei by microbiological culture obtained from blood, sputum, urine secretions from wounds or abscesses, CSF, bronchial lavage or other available specimens. Molecular biology exams are also used.
Treatment is done with the appropriate use of antibiotics. The onset is done intravenously over the period of 2 to 4 weeks, followed by oral therapy usually extended from 3 to 6 months to prevent relapse. Treatment should be as early as possible to reduce the high lethality of the disease.
There is no vaccine to prevent the disease. Prevention measures are recommended to minimize the risk of exposure, especially to people with risk factors for acquiring the disease. These include treatment of water, proper washing of contaminated food with soil, use of protective equipment such as boots and gloves in case of occupational exposure in agriculture or other activities with exposure to soil and water and compliance with laboratory biosafety standards.
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