|University of New South Wales
|Neglected Tropical Diseases; Scabies; Impetigo; Public Health; Epidemiology
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Scabies is a neglected tropical disease (NTD) that contributes greatly to global morbidity and mortality. Caused by infestation with a microscopic mite, scabies is responsible for a wide range of infections including impetigo, abscesses and cellulitis that can lead to serious complications such as septicaemia, kidney disease and rheumatic heart disease. Despite the apparent burden of disease in many countries, the worldwide prevalence of scabies is uncertain. There have been few large-scale surveys of scabies prevalence or risk factors and control strategies have often proven to be ineffective, short-term solutions. This thesis aimed to provide new information on the occurrence and risk factors for scabies and impetigo and on control strategies aimed at eliminating scabies as a public health problem in resource-poor settings. After an overall introduction to the topic, the thesis presents a systematic review of published studies on scabies and impetigo prevalence. The review found that scabies prevalence varied significantly between regions and communities with studies reporting data ranging from 0.2% to 70%. Most regions reported prevalence greater than 10% but overall scabies and impetigo prevalence were highest in the Pacific and particularly high in children. The next chapter reports on the world’s first national population-based survey of scabies and impetigo to evaluate the magnitude of the problem and found that one in four adults and one in two children had scabies after surveying 10,000 people across Fiji. Effective treatments are available for scabies but in populations where the disease is endemic reinfestation can occur rapidly even when contacts are treated. Mass drug administration (MDA) has proven to be successful for the control of other NTD. To strengthen the evidence-base for MDA for scabies control, a comparative trial was undertaken in Fiji and showed that MDA was safe and highly effective particularly with ivermectin as primary agent. These results demonstrated the potential role of MDA in addressing a serious cause of illness in many developing countries. The baseline data from the trial were also analysed to identify risk factors for scabies. Scabies was strongly associated with overcrowding and age and was a major risk factor for impetigo. This burden of disease in resource-poor settings highlights the need to undertake research to investigate strategies for public health control of scabies and impetigo at population level. Advisors/Committee Members: Kaldor, John, Kirby Institute, Faculty of Medicine, UNSW, Steer, Andrew, Murdoch Children's research Institute, whitfeld, Margot, St Vincent's Hospital Sydney.