BackgroundThis study aimed to estimate rates of chlamydia incidence and re-infection and to investigate the dynamics of chlamydia organism load in prevalent, incident and re-infections among young Australian women.Methods1,116 women aged 16 to 25 years were recruited from primary care clinics in Australia. Vaginal swabs were collected at 3 to 6 month intervals for chlamydia testing. Chlamydia organism load was measured by quantitative PCR.ResultsThere were 47 incident cases of chlamydia diagnosed and 1,056.34 person years of follow up with a rate of 4.4 per 100 person years (95% CI: 3.3, 5.9). Incident infection was associated with being aged 16 to 20 years [RR = 3.7 (95%CI: 1.9, 7.1)], being employed [RR = 2.4 (95%CI: 1.1, 4.9)] and having two or more new sex partners [RR = 5.5 (95%CI: 2.6, 11.7)]. Recent antibiotic use was associated with a reduced incidence [RR:0.1 (95%CI: 0.0, 0.5)]. There were 14 re-infections with a rate of 22.3 per 100 person years (95%CI: 13.2, 37.6). The median time to re-infection was 4.6 months. Organism load was higher for prevalent than incident infections (p<0.01) and for prevalent than re-infections (p<0.01).ConclusionsChlamydia is common among young women and a high proportion of women are re-infected within a short period of time, highlighting the need for effective partner treatment and repeat testing. The difference in organism load between prevalent and incident infections suggests prevalent infection may be more important for ongoing transmission of chlamydia.

Background:Trichomonas vaginalis, which aVects at least 170 million individuals globally, may increase the risk of transmission of HIV and predispose pregnant women to premature rupture of membranes and early labour. Objective: To more clearly define the epidemiology of trichomoniasis and to develop a mathematical model of disease transmission dynamics in order to explore various treatment strategies. Design: A deterministic model of trichomoniasis was constructed. Parameter values were set to fit the model to known endemic prevalence levels of Trichomonas vaginalis. Two treatment interventions ("screening" and "syndromic management") were simulated. Results: The age specific prevalence of the disease was seen to diVer from other STDs in a number of studies. Parameter fitting indicates that the average duration of infection in women is at least 3-5 years and approximately 4 months for men. "Syndromic management" (that is, treating only those with symptoms of disease) had minimal eVect upon the endemic prevalence of disease even at high levels of coverage. "Screening" (that is, identification of individuals with both symptomatic and asymptomatic infection) was shown to be the most eYcient method of control, but was sensitive to the screening interval. Conclusions: The control of trichomoniasis seems to have been a success in developed countries because of the regular access to health care, whereas it has remained endemic in many developing countries where control may only be possible by regular screening and treatment. However, without a large investment in services, success in controlling trichomoniasis is likely to be transitory. (Sex Transm Inf 2000;76:248-256)

The control of sexually transmitted diseases (STDs) in remote rural communities would be enhanced by a sensitive self-administered method for the detection of asymptomatic infection. Results of conventional methods for the detection of STDs were compared with results of tampon-collected specimens analyzed by polymerase chain reaction (PCR) for 480 women. Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis were detected by routine methods in 4 (1%), 14 (3%), and 41 (9%) samples, respectively, while PCR detected these organisms from 52 (11%), 26 (5%), and 75 (16%) tampons, respectively. The detection of each organism was significantly greater by PCR in tampon-collected samples than by routine conventional methods (P < .01). Discrepant results were confirmed by separate primers in 40 of 48 specimens for N. gonorrhoeae, in 11 of 12 specimens for C. trachomatis, and in 31 of 32 specimens for T. vaginalis. Tampons tested by PCR provide an acceptable and sensitive method for detection of STDs in women living in remote areas.

The prevalence of genital chlamydial infection in Indigenous Australians and young adults is unacceptably high and quality epidemiological studies are urgently required to supplement the routinely collected national notification data.