Objectives: Detailed knowledge of the spatial distribution of disease is required to inform service delivery and plan effective interventions. In order to further elucidate the spatial epidemiology of three common sexually transmitted infections (STIs), our aim was to detect and describe any significant spatiotemporal clustering of gonorrhea, chlamydia or syphilis cases in New South Wales.
Methods: Eleven years of notified STI case data were analyzed. Calculation of age- and sex-stratified incidence rates was followed by spatiotemporal cluster analyses to investigate differences in the epidemiology of gonorrhea, chlamydia and syphilis.
Results: More than one-third of all gonorrhea, chlamydia and syphilis cases in New South Wales were detected within cluster areas. Gonorrhea cases were the most highly clustered, followed by syphilis, then chlamydia. Clusters were highly significant, and relative risk estimates ranged from 1.6 to 22.9.
Conclusion: Our findings establish the high degree of geographic heterogeneity in STI incidence in New South Wales and indicate that postal area of residence is an important predictor of STI incidence. Geographical surveillance could be incorporated into routine STI surveillance to identify populations in need of intervention. The evidence presented in this report indicates a need to implement geography-specific and phase-appropriate STI prevention and control strategies.