Buruli (Bairnsdale) Ulcer
Buruli (Bairnsdale) Ulcer
Buruli ulcer, also called Bairnsdale ulcer, is a chronic, infectious disease caused by the bacterium Mycobacterium ulceranus. This bacterium is a member of the family Mycobacteriaceae, the same family that includes the bacteria responsible for tuberculosis and leprosy.
Infection from the disease leads to deformation and destruction of blood vessels, nerves, soft skin tissues, and, occasionally, bones. Large ulcers often form on the body, usually on the legs or arms. The name Buruli is often associated with the infection because of its widespread incidence during the 1960s in Buruli County (now Nakasongola District) of Uganda.
Buruli ulcer disease was first discovered in Africa. It was described by Scottish explorer James Augustus Grant (1827–1892) in the book A Walk Across Africa that he published after his equatorial African journeys. During an expedition, Grant described his infected leg as being stiff and swollen and, later, discharging bodily fluids. His account is considered the first factual description of the disease.
In the late 1890s, British physician Sir Albert Cook described skin ulcers found on Uganda natives and, in the late 1940s, Australian professor Peter MacCallum described the disease in the Bairnsdale district of south-western Australia. These two scientists are credited with first discovering that M. ulceranus caused the disease.
The M. ulceranus bacterium is commonly found in still or slowly moving water sources (such as swamps, ponds, and lakes), during flooding, and in small aquatic animals (such as insects). Humans are infected by contact with insects or with contaminated materials from water sources. Scientists have not yet determined the mode of transmission. According to the World Health Organization (WHO), infections occur in all ages and genders, however, most infections occur in children under 15 years of age, probably because they spend more time swimming in bodies of water.
Infection usually begins as a nodule within subcutaneous fat (the pre-ulcerative stage). Eventually, fat cells die due to exposure to countless numbers of mycobacteria (any rod-shaped bacteria of genus Mycobacterium). The infection can also occur as a skin ulceration—a pimple, or nodule, on the skin (dermis). In both cases, the infection is usually painless and without fever.
Later, larger lesions develop on the skin (the ulcerative stage). The infection may heal on its own, but more commonly the disease slowly progresses with more ulcers and resultant scarring. As much as 15% of the body can be covered eventually with ulcers. As this happens, destructive and dangerous toxins called mycolactone attack the immune system and destroy skin, tissues, and bones. According to the WHO, scarring of the skin can create permanent disabilities—most commonly, restricted movement of limbs.
This disease primarily affects the limbs, but also can occur on other exposed areas. The WHO states that about 90% of lesions occur on the limbs and almost 60% occur on the lower limbs. Buruli ulcers do not occur on the hands or feet of adults. In children, the disease can occur anywhere. A painful form of the disease produces severe swelling of limbs and fever. The infection, in this case, can occur anytime—after simple wounds to more serious physical traumas. Patients not treated early often suffer long-term disabilities, such as impaired joint movement and disfiguring cosmetic problems.
Historically, Buruli ulcer has occurred in over 30 countries, primarily those with subtropical and tropical climates. These countries are in central and western Africa (such as Benin, Cameroon, Congo, Ghana, the Ivory Coast, Liberia, Nigeria, Uganda, and Zaire), Central and South America, the western Pacific (including Australia and New Guinea), and Southeast Asia. In recent years, the disease is becoming more frequent in under-developed countries, specifically, in the countries of western Africa. In fact, in such areas M. ulceranus is the third leading cause of mycobacterial infection in healthy people.
WORDS TO KNOW
BACTERIOLOGICAL STAIN: A bacterial subclass of a particular tribe and genus.
HISTOPATHOLOGY: Histopathology is the study of diseased tissues. A synonym for histopathology is pathologic histology.
LESION: The tissue disruption or the loss of function caused by a particular disease process.
MYCOBACTERIA: Mycobacteria is a genus of bacteria that contains the bacteria that causes leprosy and tuberculosis. The bacteria have unusual cell walls that are harder to dissolve than the cell walls of other bacteria.
TOXIN: A poison that is produced by a living organism.
IN CONTEXT: DISEASE IN DEVELOPING NATIONS
Due to its increased frequency in western Africa and other poorer parts of the world, the WHO, in 1998, highlighted the plight of Buruli ulcer patients with its Global Buruli Ulcer Initiative (GBUI). In 2004, the World Health Assembly resolved to improve the research, detection, and control of Buruli ulcer.
SOURCE: World Health Organization
Diagnosis of Buruli ulcer is usually made from the ulcer that appears in an infected area. Tests performed to confirm a diagnosis of Buruli ulcer include polymerase chain reaction (PCR, a technique that copies a specific DNA [deoxyribonucleic acid] sequence), Ziehl-Neelsen stain (a bacteriological stain that identifies mycobacteria), culture of M. ulceranus (ulcer or tissue biopsies), and histopathology (tissue biopsies).
The treatment of Buruli ulcer usually involves the surgical removal of the lesion. This treatment is normally successful when performed early in the infection. Treatment that occurs in later stages of the infection may require long-term care with extensive skin grafting. The WHO recommends that rifampicin and streptomycin, two antibiotic drugs, be used together for eight weeks to reduce the need for surgery. According to WHO statistics, such treatment leads to complete healing of the lesion in nearly 50% of the cases. Currently, experimental drugs are being tested. These include diarylquinoline, epiroprim and dapsone, rifampicin, and sitafloxacin. Besides antibiotic therapy, surgery to remove necrotic tissue, repair skin defects, and correct deformities is often performed.
A bacille Calmette-Guérin (BCG) vaccination, according to the WHO, provides short-term, but limited, protection. Medical scientists are investigating more advanced forms of vaccinations. For the time being, once Buruli ulcer disease has reached an advanced stage, medical professionals can only help to reduce suffering and disabilities.
Buruli ulcer disease is one of the most ignored tropical diseases. Unfortunately, it is also one of the most treatable tropical diseases. The family of bacteria that cause Buruli ulcer also cause other serious diseases in mammals, including leprosy and tuberculosis. However, these diseases have garnered much more attention that Buruli ulcer disease. Although Buruli ulcer disease is found around the world, there is limited knowledge about the infection. Such ignorance of the disease is most likely due to the fact that it primarily affects the poorest of rural areas, coupled with insufficient knowledge among health workers and the general public about the disease and inaccurate diagnoses. As a result, only limited reporting of the disease occurs.
In February 2007, a team of researchers lead by Australian scientist Tim Stinear published the entire genome sequence of M. ulceranus. Such important information should help to stimulate new research into diagnostic tests, drug treatments, and vaccines. In fact, scientists are currently developing a diagnostic test that can be used locally so that treatment can be done quickly and inexpensively.
Lee, Bok Y., ed. The Wound Management Manual. New York: McGraw Hill, 2005.
Amofah, George, et al. “Buruli Ulcer in Ghana: Results of a National Case Search.” Emerging Infectious Diseases 8 (February 2002): 167–170. Also available online at: <http://www.cdc.gov/ncidod/eid/vol8no2/pdf/01-0119.pdf>.
Armed Forces Institute of Pathology. “Buruli Ulcer.” February 4, 2004. <http://www.afip.org/Departments/infectious/bu/> (accessed April 24, 2007).
World Health Organization. “Global Buruli Ulcer Initiative (GBUI).” <http://www.who.int/buruli/en/> (accessed April 24, 2007).