Arthritis in the highlands of Papua New Guinea

Focus on systemic lupus erythematosus in indigenous Australians: towards a better understanding of autoimmune diseases

The incidence and prevalence of autoimmune diseases such as rheumatoid arthritis, primary Sjögren syndrome, scleroderma and systemic lupus erythematosus (SLE) varies with geography and ethnicity. For example, SLE is reported to be more common in populations such as African-Caribbeans and Indigenous Australians (IA). As well as socio-economic status, variation in severity of disease may also show ethnic variability. The initial presentation of SLE in IA, in the context of a unique genetic background and distinctive environmental influences, is often florid with a recurring spectrum of clinical phenotypes. These clinical observations suggest a unique pathway for autoimmunity pathogenesis in this population. For instance, the high prevalence of bacterial infections in IA, particularly group A streptococcus, may be a potential explanation not only for increased incidence and prevalence of SLE but also the commonly florid acute disease presentation and propensity for rapidly progressive end organ threatening disease. This article will review the state of research in autoimmune disease of IA, consider key findings related to autoimmune disease in this population and propose a model potentially to explain the involvement of innate immunity and chronic infection in autoimmune disease pathogenesis. Ultimately, understanding of SLE at this level could affect management and result in personalised and targeted therapies to improve the health status of IA as well as better understanding of SLE pathogenesis per se.

Insights into the Role of Infection in the Spondyloarthropathies

Certain infections play an important role in the pathogenesis of the human leukocyte antigen (HLA)-B27-associated reactive arthritis. Whether infections play a role in other forms of spondyloarthropathies is not as clear. The role of HLA-B27 as an antigen-presenting molecule is important in the pathogenesis of these diseases. Recent evidence has been obtained indicating that this molecule may have other functions unrelated to antigen-presentation in the interaction of reactive arthritis-triggering microbes and host. This paper reviews the recent studies on the role of infection in the spondyloarthropathies.

Rheumatic disease and the Australian aborigine

OBJECTIVE

To document the frequency and disease phenotype of various rheumatic diseases in the Australian Aborigine.

METHODS

A comprehensive review was performed of the archaeological, ethnohistorical, and contemporary literature relating to rheumatic diseases in these indigenous people.

RESULTS

No evidence was found to suggest that rheumatoid arthritis (RA), ankylosing spondylitis (AS), or gout occurred in Aborigines before or during the early stages of white settlement of Australia. Part of the explanation for the absence of these disorders in this indigenous group may relate to the scarcity of predisposing genetic elements, for example, shared rheumatoid epitope for RA, B27 antigen for AS. In contrast, osteoarthritis appeared to be common particularly involving the temporomandibular joint, right elbow and knees and, most probably, was related to excessive joint loading in their hunter gatherer lifestyle. Since white settlement, high frequency rates for rheumatic fever, systemic lupus erythematosus, and pyogenic arthritis have been observed and there are now scanty reports of the emergence of RA and gout in these original Australians.

CONCLUSION

The occurrence and phenotype of various rheumatic disorders in Australian Aborigines is distinctive but with recent changes in diet, lifestyle, and continuing genetic admixture may be undergoing change. An examination of rheumatic diseases in Australian Aborigines and its changing phenotype may lead to a greater understanding of the aetiopathogenesis of these disorders.

Culture of joint specimens in bacterial arthritis. Impact of blood culture bottle utilization

The advantage of inoculating blood culture bottles (BCB) with a bulk volume of joint fluid was studied by analyzing results for 155 positive specimens cultured in parallel in BCB and on conventional solid media. The specimens came from both natural and artificial joints of 89 patients treated in 1975-1994. One third of the specimens from patients not on antibiotics and half of the specimens from patients on antibiotics were positive by BCB culture only. Some fastidious or slow-growing organisms were detected exclusively by this method. Additional contaminants were also picked up, but the inconvenience was relatively minor. Alternative procedures for detecting microbes in joint specimens are discussed.

The spondyloarthropathies

The spondyloarthropathies occur with variable frequency in the tropics. Ankylosing spondylitis, in particular, is thought to be rare in tropical Africa, reflecting a low frequency of the HLA B27 gene. However, in the Melanesian populations of Papua New Guinea where there is a relatively high frequency of HLA B27, ankylosing spondylosis is infrequent. These diverse observations may be related to variations in B27 sub-types. Reactive arthritis is a common and important form of acute arthritis in the tropics and in Papua New Guinea at least has a strong association with HLA B27. In Africa an increasing prevalence of reactive arthritis may be related to the spread of HIV infection. Extra-articular features such as balanitis and enthositis are helpful pointers to the diagnosis. Disseminated gonococcal infection and tuberculosis must always be considered and treatment offered if doubt exists. The mainstay of treatment of reactive arthritis is, as always, an anti-inflammatory drug, supplemented by hydrocortisone injections; docycline is available for chlamydia-triggered arthritis and chloroquine or dapsone for more chronic, unresponsive cases.

Tropical rheumatology. Epidemiology and community studies: Asia/Pacific region

It has been recognized that the remarkable decline in infant mortality and the extension in human lifespan involving both developing and developed countries alike, has been influenced by social and economic developments and public health orientated measures (such as clean water and sewerage) rather more than by developments in medical research. However, the identification of important disease risk factors for a number of common conditions such as smoking, solar exposure, dietary fat and alcohol has led to further reductions in disease prevalence and mortality, at least in some countries. The varied success of strategies to reduce the mortality from circulatory, nutritional and diseases due to infection has had the predictable result of leaving communities more exposed to the chronic non-communicable diseases, especially those affecting the elderly. The COPCORD community-based studies, carried out largely in tropical Asia/Pacific countries, have indicated that the burden of musculoskeletal conditions as far as pain and disability, as well as from an economic point of view, are substantial and WHO has called for increased research and educational activities into the causes and consequences of chronic disease and in particular rheumatic diseases. To the problems of an increasing ageing population can be added the rapid growth of urban populations, new occupational stresses, lifestyle changes and a number of other factors (WHO, 1984). The common community-based rheumatic diseases are not RA or SLE that dominate admissions to hospital arthritis clinics. Pain and disability are most often caused by osteoarthritis, especially knee OA, and various soft tissue rheumatic problems producing neck, back, shoulder and elbow pain. Viral and reactive arthritis cannot be ignored and the complications from osteoporosis (although not normally considered a rheumatic condition), are a significant threat to ageing populations worldwide. It is clear that for many of these conditions, certain risk factors have been identified and that preventative strategies are becoming available although far more detailed research is still required (Wigley, 1993). Community education is an essential part of prevention and treatment and the ILAR-sponsored publication Aches and Pains--Living with Arthritis and Rheumatism (Hampton, 1992) is available in at least 10 different languages and fills an important need. Education helps to influence not only knowledge but also skills and attitudes.(ABSTRACT TRUNCATED AT 400 WORDS)