Evidence of stable HIV seroprevalences in selected populations in the Democratic Republic of the Congo.

OBJECTIVE: To determine current data on HIV infection and to document changes and trends of HIV seroprevalence in selected populations over time in the Democratic Republic of the Congo (DRC; former Zaïre). METHODS: In February 1997, a large serosurvey was conducted on selected population groups from Kinshasa (capital city), Mbuji-May (southeast) and Bwamanda (northwest). Samples obtained from pregnant women, tuberculosis patients, commercial sex workers, blood donors and sexually transmitted disease patients were screened for the presence of HIV antibodies by a rapid assay and a commercial enzyme-linked immunosorbent assay. All reactive specimens were confirmed and discriminated by a line immunoassay, and were further tested for the presence of HIV-1 group O antibodies. Our results were compared to data reported in previous studies in Kinshasa. RESULTS: Of a total 1970 samples collected, 219 (11.1%) were HIV-1-reactive and seven (0.3%) were dually reactive to HIV-1 and HIV-2. No case of HIV-1 group O or HIV-2 infection was diagnosed. HIV seroprevalence in pregnant women was 3.1% (16 out of 511), 6.3% (19 out of 300) and 1.5% (one out of 65) in Kinshasa, Mbuji-Mayi, and Bwamanda, respectively. HIV seroprevalence in tuberculosis patients was 26% (52 out of 200), 28% (17 out of 60), and 35.3% (29 out of 83), respectively. HIV seroprevalence among blood donors was 3.1% in Kinshasa and 2.8% in Mbuji-Mayi. Compared with data from previous studies performed in Kinshasa, no substantial change in HIV infection rates was observed among the selected population groups. CONCLUSIONS: Our results show that HIV prevalence rates have remained relatively unchanged in selected populations despite the political instability and poor environment observed since 1991 in DRC. It also shows the presence, still at very low rate, of dual HIV-1/HIV-2 seropositivity and a growing problem of HIV infection in rural areas. In contrast to other Central African countries, no HIV-1 group O infections were detected in DRC.

Prevalence of HIV-1 p24 antigenemia in African and North American populations and correlation with clinical status.

Sera from 622 individuals and culture supernatants from three HIV-1 viral isolates were assayed for HIV-1 p24 antigen to investigate the frequency of p24 antigenemia in African and North American populations using three commercial HIV-1 p24 antigen assays (Coulter, Du Pont, and Abbott). The prevalence of p24 antigenemia in 89 hospitalized Zairian AIDS patients was significantly lower than in 47 clinically comparable AIDS patients in the USA (17 versus 48%, P less than 0.0001). Prevalence of p24 antigenemia in sera from 200 asymptomatic HIV-1-infected individuals was also lower in individuals from Zaire compared with 83 individuals in the USA (3.5 versus 7%). In African individuals, antigenemia prevalence increased with advanced clinical status: 8% in ambulatory AIDS patients, 17% in hospitalized AIDS patients and 18% in postmortem AIDS patients. Acid hydrolysis treatment of sera from 63 Zairian AIDS patients initially negative for p24 antigen showed an 11% positivity rate confirmed by neutralization, suggesting that immune complexing of p24 antigen may play a role in the observed lower p24 antigenemia rates reported for African individuals.