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Abstract
Syphilis has been resurgent in Australian cities over the last 15 years. Almost all cases are in men who have sex with men (MSM). Despite numerous health promotion and testing campaigns diagnoses continue to rise. The aim of this thesis is to investigate clinical and epidemiological aspects of the syphilis epidemic in Sydney, in order that future public health responses are informed by the best evidence. The thesis contains a range of studies that cover several research designs and analytic approaches.
ln order to understand how the trends observed in Australia compare to those seen internationally, study 1 investigates syphilis notifications among 31 high income countries. High-income countries were chosen as comparators because their gross demographic product is unlikely to place significant restrictions on treatment and health services, and therefore differences in syphilis notifications between countries are more likely to be related to social, behavioural or structural public health responses than limited resources. The changing notification pattern seen in Sydney is reflected in most other developed countries.
It is important to understand the use and role of new diagnostic tests. Study 2 presents clinical information on the application, utility and treatment response and reinfection of polymerase-chain reaction confirmed syphilis. lt also presents data on treatment, which frequently differs from guidelines.
Study 3 focuses on antimicrobial resistance in Treponema pallidum, and reports the first Australian data showing that this organism has acquired resistance to the macrolide class of antibiotics which therefore should not be used. Risk factors for drug resistance are also analysed.
Study 4 evaluates a model of care using point-of-care tests for syphilis outside of the clinic, and shows that community-based testing is able to access high risk men who are recommended to frequently test for syphilis.
These studies are synthesised in the discussion and recommendations are provided on clinical, programmatic, and future research directions to address syphilis epidemics among MSM.