Increased notifications of infectious syphilis among young Aboriginal and Torres Strait Islander people of northern Australia were first reported in northwest Queensland (Qld) in January 2011, followed by the Northern Territory (NT) in July 2013 and the Kimberley region of Western Australia (WA) in June 2014. In response to the increase, the Communicable Disease Network Australia formed a Multijurisdictional Syphilis Outbreak Working Group (MJSO) to facilitate coordination of the public health response. An outbreak case definition was developed and defined as any case of infectious syphilis in an Aboriginal or Torres Strait Islander person notified in an outbreak region, or any case of infectious syphilis that was a sexual contact of a confirmed outbreak case.
Between January 2011 and December 2015, 790 cases of infectious syphilis were reported in the outbreak. Of all cases, 45% were male, 75% were aged 15-29 years, and most resided in remote and outer regional areas. Seven congenital syphilis cases associated with the outbreak were reported; 2 were stillborn and 1 died in the neonatal period. Controlling the outbreak is a public health priority, as elevated rates of infectious syphilis increase the risk of additional cases of congenital syphilis, and potentially contribute to HIV transmission given syphilis infection is associated with increased risk of HIV acquisition. The public health response to the outbreak includes empirical treatment of cases and contacts, increased opportunistic testing and community screening, timely and rigorous contact tracing, achieving recommended antenatal screening, and Aboriginal and Torres Strait Islander community engagement. Laboratories provide quality diagnostic testing and technical expertise in interpretation of results which are integral to the outbreak response. Laboratories could further contribute to the response by providing more detailed and timely testing data for outbreak regions which would assist with interpretation of disease trends.
In summary, the outbreak of infectious syphilis in northern Australia is a major public health concern requiring continued and coordinated public health responses across affected jurisdictions, and diagnostic support from laboratories.