title: HIV-1 infection prevalence and incidence trends in areas of contrasting levels of infection in the Kagera region, Tanzania, 1987-2000.
abstract: 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.
authors.affiliation: Department of Epidemiology and Biostatistics, Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania. gkwesigabo@muchs.ac.tz
authors.forename: Gideon
authors.initials: G
authors.lastname: Kwesigabo
authors.forename: Japhet
authors.initials: J
authors.lastname: Killewo
authors.forename: Willy
authors.initials: W
authors.lastname: Urassa
authors.forename: Joe
authors.initials: J
authors.lastname: Lugalla
authors.forename: Maria
authors.initials: M
authors.lastname: Emmelin
authors.forename: Aldin
authors.initials: A
authors.lastname: Mutembei
authors.forename: Fred
authors.initials: F
authors.lastname: Mhalu
authors.forename: Gunnel
authors.initials: G
authors.lastname: Biberfeld
authors.forename: Stig
authors.initials: S
authors.lastname: Wall
authors.forename: Anita
authors.initials: A
authors.lastname: Sandstrom
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology; D015497:HIV-1; D006801:Humans; D015994:Incidence; D008297:Male; D015995:Prevalence; D013636:Tanzania / Q000453:epidemiology