Epstein-Barr virus (EBV) and Kaposi's sarcomaassociated herpesvirus (KSHV) are human herpesviruses that differ dramatically in their geographic prevalence. EBV seropositivity in healthy populations is .90% worldwide. KSHV seropositivity is low (0-5%) in the United States, Canada, and Europe; intermediate (7-24%) in Italy and the Mediterranean; and high (23-70%) in sub-Saharan Africa [1] [2] [3] [4] . Seroprevalence for KSHV increases in individuals coinfected with human immunodeficiency virus 1 (HIV-1) and, in the United States and Europe, in men who have sex with men [5] [6] [7] . Primary infection with EBV can cause infectious mononucleosis, and both EBV and KSHV are associated with human cancers. EBV is associated with nasopharyngeal carcinoma, African Burkitt's lymphoma, a subset of Hodgkin's lymphoma, AIDS-related lymphoma, gastric carcinoma, peripheral T cell lymphoma, and posttransplant and other lymphoproliferative diseases in the immunodeficient [8] . KSHV is associated with Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Immunosuppression, such as that imposed by concurrent HIV-1 infection or transplantation regimens, increases the incidence of some of these virus-associated cancers [8, 9] .