[Cohort study of HIV infection among drug users in Ruili and other counties in Yunnan Province, China].

In 1993, a second survey was conducted in Ruili City and other two counties, where a cohort study field was established last year. Seven hundred and fifty five drug users and one hundred and two spouses of HIV infected IDUs were interviewed. Nine samples among 54 from 89 IDUs in cohort were tested as seroconversion. The seroconversion rate (incidence rate) in IDUs (per hundred person years) in Ruili, Longchuan, and Luxi as well were 40.0, 12.2 and 0, respectively in 1993, comparing to 43.2, 12.2 and 0 in 1992. Thirty eight were tested as positive among 108 samples from 116 newly recruited IDUs. The seroprevalence rates in this three counties were 85.7%, 40.0% and 0 in 1993, comparing to 81.8%, 44.6% and 5.1% in 1992. A coordination of the level between seroconversion and seroprevalence was observed. A increasing trend of seroprevalence among the spouses of HIV positive IDUs was found, the seroprevalence rate were 3.1% in 1990, 9.8% in 1992 and 7.4% in 1993. More attention should be paid to Luxi where the ratio of intravenous drug using increased rapidly, although fewer positives and later starting of drug using was found in this county.