Increasing Kaposiʼs sarcoma-associated herpesvirus seroprevalence with age in a highly Kaposiʼs sarcoma endemic region, Zambia in 1985

Abstract

Background: Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is a newly discovered virus found in all forms of KS. In the United States, KSHV infection appears to be most common amongst individuals at high-risk for KS. Preliminary data from Africa suggest that KSHV infection may be much more common in the general population. Objective: To examine the KSHV seroprevalence and age-specific patterns of infection in an African country with high rates of KS. Design: Cross-sectional seroprevalence study. Methods: Sera were taken for a hospital-based HIV seroprevalence study conducted in August 1985 in Lusaka, Zambia at a time when HIV was just becoming epidemic in this area. A total of 251 sera were randomly sampled and examined for antibodies against latent and lytic antigens to KSHV. KSHV seroprevalence was compared with demographic and clinical variables using χ² test for linear trend and odds ratios and 95% confidence intervals. Results: Overall, 58% of persons aged 14–84 years were KSHV-seropositive. KSHV seroprevalence increased linearly with age (P = 0.04) and was inversely related to years of education (P = 0.015). In contrast, HIV infection peaked in those aged 20–29 years and was positively related to years of education (P = 0.015). No association between KSHV and gender, marital status, or HIV serostatus was seen. Conclusions: KSHV infection was significantly more common in this region of Zambia in 1985 than it currently is in the United States. Our data are consistent with KSHV being well-established in this region prior to 1985 and that continued adult transmission of the virus was occurring. The high seroprevalence in the adolescent age-group and the relatively linear increase in prevalence with age suggest that non-sexual modes of transmission may be important for KSHV transmission in Africa.