Evaluation of a new fourth-generation microwell enzyme-linked immunosorbent assay for detection of HIV-1 subtype B and E antibodies.

The recent fourth-generation enzyme-immunoassays have been used to increase the sensitivity for detecting HIV-1 antibodies and reduce the window period of HIV infection. The HIV antigens utilized in those assays were prepared from HIV-1 clade B which is different from HIV-1 subtypes circulating in Thailand. We evaluated 323 HIV-1 seropositives either B or E subtype to determine whether they were detected with the new combined anti-HIV and the p24 Ag assay. Under evaluation we found that this enzyme immunoassay manufactured by Organon Teknika showed the high sensitivity and specificity with a greater delta (delta) value with B than E subtypes samples (+15.29 vs +5.73).

Sexual behavior of young men in Thailand: regional differences and evidence of behavior change.

An anonymous, self-administered behavioral survey was conducted in Royal Thai Army (RTA) conscripts from 19 provinces throughout Thailand in May 1996. All (to a maximum of 350) Thai men who entered the RTA in each province were selected. Data from 5474 men were included in this analysis. High-risk behaviors were reported nationwide; however, some regional differences were found. Men from the upper North were more likely to have had a commercial sex worker (CSW) as their first sexual partner (42%) than men from any other region. However, in the past year, reported sex with CSWs in the upper North (41%) was similar to or lower than those in other regions. Consistent condom use with CSWs was higher in the North than in any other region. Condom use at first sex with CSWs increased with later years at first sex in all regions. These data suggest that past higher-risk behavior among young men in the upper northern part of Thailand may have contributed to the concentration of the HIV epidemic in that region. Risk behaviors, particularly unprotected sex, appear to be decreasing nationwide.

PIP: The HIV behavioral risk factors associated with temporal and regional trends in HIV prevalence were investigated in a 1996 survey of 5474 Royal Thai Army conscripts from 19 provinces. 89% of respondents were 21 years of age and 77% were single. HIV prevalence was highest among men from the upper north (4.3%), followed by 2.6% in the central region, 2.4% in Bangkok, and 1.2% in the southeast. The median age at first intercourse was 17 years. Among sexually experienced men, a significantly higher proportion of those from the upper north (42%) had their first such encounter with a commercial sex worker (CSW). However, sex with CSWs during the year preceding the survey was similar or less frequent among men from the upper north (41%) compared with other regions. Also, significantly more men from the upper north (62%) used condoms every time with a CSW. Overall, 10% (range, 8-12%) reported having had sex with a man and 13% reported symptoms of a sexually transmitted disease (STD). Men whose sexual initiation occurred after 1990 were more likely to use condoms with a CSW partner. The decrease in sexual risk factors documented in this survey is consistent with national declines in HIV prevalence, especially in the upper northern region, after 1992. The increase in condom use with CSWs coincides with the 100% condom campaign initiated in 1991, intensified STD control efforts, and the emergence of AIDS deaths. Sex with non-CSW female partners, where condoms are rarely used, and homosexual sex require attention as situations where HIV risk may persist.