Background:  Infection with human herpesvirus-8 (HHV-8) is endemic and associated with high incidence of Kaposi’s sarcoma (KS) in both adults and children. KS is coincident with the HIV-1 epidemic thus, we hypothesized that HHV-8 infection occurs early in the life of the infant and is a function of the HIV status of both the infant and the mother. Here we present cross sectional and longitudinal serological data defining prevalence and correlates of HHV-8 infection in Zambian children.

Methods:  Between September 1998 and October 2000, we recruited mother/infant pairs at the time of delivery at the University Teaching Hospital in Lusaka, Zambia, and followed them prospectively. Plasma samples collected at 6, 12, 24 and 36 months were tested for HHV-8 and for HIV-1 at 24 and 36 months. HHV-8 antibodies were first tested by a lytic BC-3 monoclonal immunofluorescence assay and later confirmed by a novel IFA based on baculovirus expression of either lytic or latent genes in Sf-9 insect cells (Sf-9 IFA). HHV-8 antibody titers were determined by the BC-3 lytic assay only.  HIV-1 antibodies were detected using two standard HIV-1 test kits.

Results:  The overall HHV-8 infant cross-sectional infection rates at 12, 24, and 36 months (n = 681, 669, and 393) were 18%, 27%, and 25%, respectively. Within this same cohort, 269 children were followed up longitudinally (at all time-points) and their HHV-8 seroprevalence at 12, 24, and 36 months was 22%, 23%, and 27%, respectively. Seroconversion rates are also reported.

Conclusions:  Our data show that in Zambian children, HHV-8 infection occurs early in life, reaching near maximal prevalence levels in the first 3 to 6 years of life. Children infected with HIV-1, and those born to HIV-1-infected mothers were at a higher risk of acquiring HHV-8 infections than controls. These results strongly suggest that HIV-1 is a risk factor for Zambian children acquiring HHV-8 infection.

Keywords: HHV-8; HIV-1; Seroprevalence