Impact of the 1994 expanded World Health Organization AIDS case definition on AIDS surveillance in university hospitals and tuberculosis centers in Cote d'Ivoire

Objective: To assess the impact of the 1994 expanded World Health Organization (WHO) AIDS case definition on AIDS surveillance in Cote d'Ivoire. Design: Prospective AIDS case surveillance. Methods: From March 1994 through December 1996, passive AIDS case surveillance was conducted at the three university hospitals in Abidjan, and active AIDS case surveillance was conducted at the eight tuberculosis (TB) centers in Cote d'Ivoire. Standardized questionnaires were administered and blood samples for HIV serologic testing were collected from the patients evaluated. The numbers of persons who met the modified 1985 WHO clinical AIDS case definition (Bangui definition) and the 1994 expanded WHO AIDS case definition were determined, and the clinical characteristics of these patients were assessed. Results: Of 8648 university hospital patients, 3658 (42.3%) met the clinical and/or the expanded case definition: 744 (20.3%) HIV-seropositive persons met only the expanded definition, 44 (1.2%) HIV-seropositive persons met only the clinical definition, 2334 (63.8%) HIV-seropositive persons met both definitions, and 536 (14.7%) HIV-seronegative persons met only the clinical definition. Of 18 661 TB center patients, 9664 (51.8%) met the clinical and/or the expanded definition: 5685 (58.8%) HIV-seropositive persons met only the expanded definition, none of the HIV-seropositive persons met only the clinical definition (by definition), 2625 (27.2%) HIV-seropositive persons met both definitions, and 1354 (14.0%) HIV-seronegative persons met only the clinical definition. Conclusions: Because of the inclusion of multiple severe HIV-related illnesses into the expanded definition, the number of reportable AIDS cases in HIV-seropositive patients increased 31.3% in the university hospitals, and 217% in the TB centers. The inclusion of HIV seropositivity as a criterion for the expanded definition also enhanced the specificity of AIDS case reporting, eliminating 536 cases in the university hospitals and 1354 cases in the TB centers in HIV-seronegative patients who had clinical signs of AIDS. The use of the 1994 expanded definition for surveillance purposes should be encouraged in areas of the developing world where HIV serologic testing is available.