Annual Report 2003/2004 Menzies School of Health Research
Tabled paper 1523
Tabled Papers for 9th Assembly 2001 - 2005; Tabled Papers; ParliamentNT
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Menzies School of Health Research 2003 Annual Report | Infectious Diseases Division | 9 Skin infections are quite common, and although they can cause unsightly, inconvenient and uncomfortable health problems, they are usually treatable with readily available medications. Skin infections in Indigenous populations are far more insidious. Up to 60% of children in remote Aboriginal communities in northern and central Australia, are estimated to be infected with scabies a skin disease caused by a tiny mite. The scabies mite burrows under the skin and breeds, often transmitted to others before diagnosis. Scabies cause intense itching, resulting in open skin lesions. These sores often become infected with group A streptococcus (GAS) a group of bacteria that thrive in the tropical environment of the Northern Territory and cause a massive range of diseases, including pharyngitis (strep throat), rheumatic fever, glomerulonephritis (a major kidney disease) and invasive diseases such as streptococcal toxic shock syndrome. The Skin Health program focuses on researching skin infections and infestations endemic to Indigenous communities in the NT, such as scabies and topical streptococcal infections, and their relationship to kidney disease and rheumatic fever. This relationship is of interest as some remote communities in the Northern Territory suffer the highest rates of rheumatic fever and kidney disease in the world. Our Skin Health team are also involved in an innovative collaboration with the Cooperative Research Centre for Aboriginal Health (CRCAH), in a number of laboratory, clinical and public health projects known as the Healthy Skin initiative. Forty-three thousand scabies mite cDNA clones have been sequenced so far from a goal of 50,000 in an ongoing gene discovery project that aims to significantly advance the limited amount of molecular information available about the scabies mite. Molecules of interest identified so far include similarities between scabies mite and house dust mite allergens, potential vaccine candidates, genes associated with drug resistance and potential drug targets in therapeutic studies. Extended research using DNA fingerprinting techniques continued to identify the biological species classification of the scabies mite. Previous studies suggest a single gene pool, however, our molecular study demonstrated genetic differences between mites obtained from northern Australian dogs and those on people. This discovery had important implications in scabies control programs for Aboriginal communities. Further clarification of genetic variation and understanding of the interbreeding between mite populations is important for disease and resistance control. Publication of seven papers and an additional two invited reviews in press resulting from our study into antigens, allergens and immune responses to normal and crusted scabies. Recent developments leading to expression and purification of scabies mite recombinant antigens now provides an exceptional opportunity to obtain a clearer outline of immune responses important in normal scabies and to assess differences in those with severe infestation (crusted scabies). Recent studies reveal tea tree oil could be used as a new topical treatment for scabies. Results demonstrated that tea tree oil was highly effective in killing the scabies mite in the laboratory. MSHR research team, in collaboration with international researchers in America, England and Germany have demonstrated that the group A streptococcus population in tropical Northern Australia is more diverse than elsewhere in the temperate world. An important study to determine if group A streptococcus (GAS) skin infection leads to acute rheumatic fever (ARF) is under way in two Aboriginal communities. GAS throat infections are traditionally thought to be the only cause of ARF. However, GAS is uncommonly found in the throat of Indigenous people in the NT, even though Aboriginal communities suffer the highest reported rate of ARF in the world. Results of this study could therefore have important implications for prevention and vaccine development of ARF around the world. Exciting preliminary results suggest new diagnostic blood tests may improve the accuracy of diagnosis of rheumatic fever. Skin Health MSHR 2003 Research & Education Report provides detail on all research projects and is available online at www.menzies.edu.au Key achievements TOP: Phase contrast micrograph of an adult male Sarcoptes scabiei collected from an agile wallaby in the Northern Territory. BELOW: The scabies mite burrows under the skin, causing intense itching which results in open lesions and allows a point for infections to enter the body. (Photos courtesy of Skin Health Program, MSHR)