Estimating the prevalence of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, and human papillomavirus infection in indigenous women in northern Australia

Objective: To estimate more accurately the age specific prevalence of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, and human papillomavirus infection (HPV) in indigenous women living in urban, rural, and remote areas of the "Top End" of the Northern Territory (NT). Design: Analysis of data obtained from two community based studies using self administered tampon specimens tested by polymerase chain reaction for sexually transmitted disease (STD). Data pertaining to the notifiable STDs (N gonorrhoeae and C trachomatis) were obtained from the NT health department. Patients: 1090 indigenous women (age range 12-73 years) were enrolled when they attended local community health centres, family planning clinics, and STD clinics. The majority attended clinics in their home community in the course of "well women's checks" which encourage women to undergo screening for a variety of general medical conditions. Results: The overall prevalence of T vaginalis, C trachomatis, N gonorrhoeae, and HPV was 0.25 (95% CI: 0.22-0.28), 0.11 (0.09-0.13), 0.17 (0.15-0.19), and 0.42 (0.37-0.48) respectively. Of the women found to be infected (excluding HPV), 25.5% had two or more of the above organisms detected. There was a statistically significant increase in the age specific prevalence of T vaginalis but a significant decrease with age for C trachomatis and HPV infection. There was no statistically significant change for N gonorrhoeae with age. Conclusions: STDs are hyperendemic in this population of indigenous women and the notification data significantly underestimate their prevalence. Distinct patterns of age specific prevalence were demonstrated, highlighting the need to tailor control strategies to specific epidemiological features.