January 28 (Wednesday) -- Saul Phiri (Graduate Student, School of Biological Sciences)

Kaposi's Sarcoma Associated Herpesvirus Infection in Zambian Children and the role of 
HIV-1 as a Risk Factor

Background: Infection with human herpesvirus-8 (HHV-8) is endemic and associated with 
high incidence of KaposiÕs 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 (mIFA) 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.

Conclusion: Our data show that in Zambian children, HHV-8 infection occurs early in life, 
reaching near maximal prevalence levels in the first 3-6 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.

Reference:
Brayfield et al. (2003) Postnatal human herpesvirus 8 and human immunodeficiency virus type 1 
infection in mothers and infants from Zambia. J Infect Dis. 187(4): 559-68.