Zoonotic infections in AIDS

In IDL-778

Biological and behavioural impact of an adolescent sexual health intervention in Tanzania: a community-randomized trial

Objective: The impact of a multicomponent intervention programme on the sexual health of adolescents was assessed in rural Tanzania. Design: A community-randomized trial. Methods: Twenty communities were randomly allocated to receive either a specially designed programme of interventions (intervention group) or standard activities (comparison group). The intervention had four components: community activities; teacher-led, peer-assisted sexual health education in years 5-7 of primary school; training and supervision of health workers to provide 'youth-friendly' sexual health services; and peer condom social marketing. Impacts on HIV incidence, herpes simplex virus 2 (HSV2) and other sexual health outcomes were evaluated over approximately 3 years in 9645 adolescents recruited in late 1998 before entering years 5, 6 or 7 of primary school. Results: The intervention had a significant impact on knowledge and reported attitudes, reported sexually transmitted infection symptoms, and several behavioural outcomes. Only five HIV seroconversions occurred in boys, whereas in girls the adjusted rate ratio (intervention versus comparison) was 0.75 [95% confidence interval (CI) 0.34, 1.66]. Overall HSV2 prevalences at follow-up were 11.9% in male and 21.1% in female participants, with adjusted prevalence ratios of 0.92 (CI 0.69, 1.22) and 1.05 (CI 0.83, 1.32), respectively. There was no consistent beneficial or adverse impact on other biological outcomes. The beneficial impact on knowledge and reported attitudes was confirmed by results of a school examination in a separate group of students in mid-2002. Conclusion: The intervention substantially improved knowledge, reported attitudes and some reported sexual behaviours, especially in boys, but had no consistent impact on biological outcomes within the 3-year trial period

Mass Treatment With Single-Dose Azithromycin for Trachoma

Trachoma, caused by repeated ocular infection with Chlamydia trachomatis, is an important cause of blindness. Current recommended dosing intervals for mass azithromycin treatment for trachoma are based on a mathematical model. We collected conjunctival swabs for quantitative polymerase-chain-reaction assay of C. trachomatis before and 2, 6, 12, 18, and 24 months after mass treatment with azithromycin in a Tanzanian community in which trachoma was endemic. For ethical reasons, at 6, 12, and 18 months, we gave tetracycline eye ointment to residents who had clinically active trachoma. At baseline, 956 of 978 residents (97.8 percent) received either one oral dose of azithromycin or (if azithromycin was contraindicated) a course of tetracycline eye ointment. The prevalence of infection fell from 9.5 percent before mass treatment to 2.1 percent at 2 months and 0.1 percent at 24 months. The quantitative burden of ocular C. trachomatis infection in the community was 13.9 percent of the pretreatment level at 2 months and 0.8 percent at 24 months. At each time point after baseline, over 90 percent of the total community burden of C. trachomatis infection was found among subjects who had been positive the previous time they were tested. The prevalence and intensity of infection fell dramatically and remained low for two years after treatment. One round of very-high-coverage mass treatment with azithromycin, perhaps aided by subsequent periodic use of tetracycline eye ointment for persons with active disease, can interrupt the transmission of ocular C. trachomatis infection