In Côte d'Ivoire (CI), West Africa, public health officials practice HIV sentinel surveillance by collecting blood samples from roughly three thousand pregnant women each year to estimate overall HIV prevalence. Since pregnant women have had unprotected sex by definition, their HIV prevalence is said to mirror the nation's. At clinics, health personnel draw women's blood for syphilis tests without telling them that some blood will also be tested for HIV. No informed consent is requested for the HIV test, no identifying information attached to the results, and no results revealed to the women. In theory, women's confidentiality remains intact, and the results will help public health officials request greater resources to fight HIV/AIDS where surveillance indicates the greatest need. In northwestern CI, however, HIV sentinel surveillance has occurred since 1997 without the promised benefits. Women still lack local access to free or low-cost voluntary HIV counseling and testing, much less antiretroviral medication. Consequently, the HIV counseling and testing procedures through which women might integrate biomedical ideas about HIV/AIDS into their lives remain out of reach. The question thus arises: How can we understand the ethics of sentinel surveillance practices that foster, through their secrecy, a silence about the biomedical understandings of HIV/AIDS that public health officials would otherwise promote? This paper addresses this question by contrasting synthetic local narratives about HIV/AIDS-that integrate discourses of sorcery, colonial history, perversion, and virology-with the exclusionary narrative of sentinel surveillance, which remains inaccessible to the very women who generate it.