HIV-1 infection prevalence and incidence trends in areas of contrasting levels of infection in the Kagera region, Tanzania, 1987-2000.

This study aimed at assessing the extent to which decline in HIV infection prevalence reflects decline in incidence in 3 areas with contrasting initial exposure to the HIV epidemic in the Kagera region of Tanzania. A population sample was recruited for the baseline study in 1987 through a multistage cluster sampling technique to determine HIV prevalence. Seronegative individuals identified in the baseline and subsequent studies were followed up for 3 years to yield trends in incidence that were compared for the 3 areas. The overall age-adjusted HIV-1 prevalence in the high-prevalence area of Bukoba urban declined significantly from 24.2% in 1987 to 18.2% in 1993 and later to 13.3% in 1996 (P = 0.0001). In the medium-prevalence area of Muleba, overall age-adjusted prevalence declined significantly from 10.0% in 1987 to 6.8% in 1996 and later to 4.3% in 1999 (P = 0.0003), whereas in the low-prevalence area of Karagwe the prevalence declined from 4.5% in 1987 to 2.6% in 1999 (P = 0.01). In all 3 areas, the most significant decline was consistently observed among women in the age group 15-24 years. No age group exhibited a significant upward prevalence trend. The HIV-1 incidence for Bukoba urban declined from 47.5 to 9.1 per 1000 person-years of observation in 1989 and 1996, respectively, whereas in Muleba it decreased from 8.2 to 3.9 in 1989 and 2000, respectively. Sex-specific estimates indicated a significant decline among women in the high-prevalence area of Bukoba urban from 51.5 to 9.2 per 1000 person-years at risk (P = 0.001). It is concluded that the HIV-1 epidemic in Kagera is on the decrease as reflected by the decline in HIV-1 incidence and prevalence trends particularly among the 15-24 year olds. The decline in the 3 areas of differing magnitude implies that the HIV/AIDS epidemic may be arrested early without necessarily peaking to saturation levels.

Social, cultural and sexual behavioral determinants of observed decline in HIV infection trends: lessons from the Kagera Region, Tanzania.

This paper is a follow-up of earlier findings by the Kagera AIDS Research Project (KARP), which documented declining trends in the prevalence and incidence of HIV infection in the Kagera region of Tanzania. The paper examines socio-cultural and sexual behavioral changes as possible determinants of the observed declining trends in Bukoba, the largest urban area of the region. The study used in-depth interviews, focus group discussions, field observations and ethnographic assessments to collect the required data. The findings suggest that since the initial years of the epidemic there have been significant changes in sexual behaviors, norms, values, and customs that are considered high-risk for HIV transmission. The findings show an increase in condom use, abstinence, zero grazing (sticking to one sexual partner) and uptake of voluntary HIV testing while traditional practices such as polygamy, widow inheritance, excessive alcohol consumption, and sexual networking are declining. We suggest that these changes are partly a result of the severity of the epidemic itself in the study area, and interventions that have been carried out in this area since 1987. The major interventions have included health education, the distribution of condoms, AIDS education in schools, voluntary HIV counseling and testing. These are encouraging findings that give hope and we believe that other places within Tanzania and other countries experiencing a severe AIDS crisis have much to learn from this experience. However, changes in norms and behavior are vulnerable; people in Kagera are still at risk and there is a need for continued intervention together with monitoring of the direction of the epidemic.