After the floods: Beware of ‘the great mimicker’ Melioidosis

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A father of three children, Nihal*, and his family living in Hambantota were badly affected by the May- June floods. He was 46, a diabetic with very poor sugar control. It was while the family was busy cleaning their home and trying to get back to their normal lives after the floods had receded that Nihal suddenly developed high fever, with joint pains and myalgia. He was admitted to the Tangalle Base Hospital, from where he was transferred to the Karapitiya Teaching Hospital for specialised management of severe septic shock.

According to his symptoms and signs, with a background of being a flood victim, the preliminary diagnosis was leptospirosis and he was managed with the best antibiotics and cared for in the Intensive Care Unit (ICU). Despite the collective effort of all the relevant specialties, in the ICU, he died within a few hours. The blood culture taken on admission became positive the following morning for a bacterium which was identified as Burkholderia pseudomallei causing melioidosis.

In Matara, brother and sister, seven-year-old Shehan* and three-year-old Poorni* were also affected by the floods with their home being covered with mud after the floods had receded. They helped their parents in washing and cleaning up. Both developed fever with a cough and were admitted to Matara District General Hospital and managed for pneumonia. Though they were treated with the standard antibiotics for pneumonia, the fever and other symptoms could not be resolved and they were transferred to the Karapitiya Teaching Hospital for specialized management.

Due to their poor response, the Paediatricians sought the opinion of the Microbiologist and the antibiotic regimen was changed empirically to cover the bacterium Burkholderia pseudomallei together with other bacteria-causing pneumonia. Blood was sent to the Colombo Medical Faculty’s Department of Microbiology, for testing for melioidosis. The antibody test of both children confirmed melioidosis with very high values and as the correct treatment was started without delay, both were saved.

From Beliatte, 48-year-old Nimal* who is also a diabetic was being treated for melioidosis, more than six weeks after the floods during which his village was flooded. Initially, he had come with an abscess on the hand and by the time he was transferred to the Karapitiya Teaching Hospital, he had developed multiple lung abscesses. Two of his blood cultures were positive for Burkholderia pseudomallei while the antibody titre was more than 10,000.

These case studies give a very important message to doctors – keep in mind melioidosis when treating flood victims with fever.
They can present with severe pneumonia; kidney or urinary tract infections; septic arthritis; abscesses in the internal organs including lungs, liver, kidneys, spleen and brain; chronic wounds or cellulitis; abscesses in deep muscles or subcutaneous tissue; or any type of prolonged high fever. Often the condition may be misdiagnosed as leptospirosis or even Dengue Haemorrhagic Fever during the rainy season when both these diseases are also doing their rounds.

Melioidosis patients, however, can present with this condition even weeks after the floods have receded as the incubation period is very variable and can be weeks to months in some cases.Though melioidosis was considered uncommon in Sri Lanka, according to surveillance and research conducted by Senior Lecturer in Microbiology, Dr. Enoka Corea of the Colombo Medical Faculty, increasing numbers have been reported recently.

The disease is most prevalent in northern Australia, Southeast Asia and China. The causative bacterium, Burkholdeia pseudomallei can infect humans through inhalation, ingestion or direct contact of contaminated soil or water. Farmers, gardeners and manual workers are at continuous risk of acquiring the infection and the number of patients can go up with the rains and floods which expose deep layers of soil which might contain the bacterium.

There may be many people who will remain asymptomatic despite being infected thanks to the defence systems of the human body. However, when immunity reduces, as in chronic diseases such as diabetes especially with poor control, chronic kidney disease, chronic liver disease, thalassemia, malignancy and so on, or when the patient is on immunosuppressive medicine such as high-dose steroids or anti-cancer therapy or in alcoholics and smokers, the disease comes out with different symptoms and signs which can mimic any other disease. This is why melioidosis is called ‘the great mimicker’.

After the heavy rains and floods in the Southern Province, Karapitiya Hospital’s Microbiology Department identified about eight flood victims with melioidosis. Three died before the diagnosis came and the patient with lung abscesses is still recovering.

In the past 2½ years, we have identified and treated 56 patients with melioidosis at the Karapitiya Hospital, with only six deaths. As the incubation period for the disease is very unpredictable and can be two weeks to even months or years, it is crucial to think of melioidosis when tell-tale pictures are seen. According to our experience now the disease should be suspected even among small children who present with clinical evidence and risky exposure.

The diagnosis of the disease requires clinical expertise on the part of the doctor. The bacterium can be cultured from blood, sputum, urine or abscess fluid depending on the site of the infection. It would also be good to send two-millilitre blood sample to the Colombo Medical Faculty for anti-melioidosis antibody testing.

It is important to remember that even in very acute disease with a positive culture from the clinical sample, the antibody level can be as low as 1/40. Therefore, low antibody values also should be considered significant, whether the culture is positive or not, if the entire clinical picture fits the diagnosis.
Once treatment is started, it usually requires a minimum of two weeks of intravenous antibiotics and then a minimum of 8-10 weeks of oral antibiotic treatment as well. While the intravenous phase controls the disease severity and resolves the symptoms and signs, the oral phase helps to eradicate the bacterium totally from the body.

As it requires long-term antibiotic treatment, the patient should be counselled on the nature of the disease, the side-effects of the drugs, the risks and the prognosis. If not, there is a chance that some patients might stop taking the drugs when the symptoms are resolved which can lead to a relapse in the future. Currently, we are treating a patient with multiple splenic abscesses who came with a severe relapse because of poor medication compliance.
The disease is hardly ever contagious, so there is no need to worry about looking after the patients in the hospital or at home. The disease can be treated successfully if the diagnosis is made early to control the severity and kill the causative bacterium.

The management of patients with melioidosis involves much team work in which the Microbiologists, the Physicians, the Paediatricians, the Nephrologists, the Radiologists and sometimes the Surgeons and all doctors in a unit have to dedicate their time, knowledge and experience to the maximum to send the patients home alive.

* Names of patients have been changed to maintain confidentiality
(Dr. Bhagya Piyasiri is the Consultant Microbiologist of the Karapitiya Teaching Hospital

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