Geographic Heterogeneity of Prevalence of the Human Herpesvirus 8 in Sub-Saharan Africa: Clues About Etiology

Abstract

Human herpesvirus 8 (HHV-8, or Kaposi sarcoma [KS]-associated herpesvirus, KSHV) is a necessary but insufficient cause of KS, as KS develops in few HHV-8-infected persons. In sub-Saharan Africa, marked differences in the geographic distribution of HHV-8 and KS suggest that environmental cofactors influence HHV-8 transmission, control, and progression to KS. However, a direct comparison of HHV-8 prevalence estimates is complicated because studies used different serologic assays and analytic methods. We assessed HHV-8 seropositivity in several African countries with heterogeneous environments and varying KS incidence using a unified approach. HHV-8 antibodies were measured among 3196 adults (aged 20+ years) and 2404 children (aged <20 years) from five studies in four sub-Saharan countries in Africa. Serum samples were tested by the same laboratory using K8.1 and orf73 enzyme immunoassays. Children's HHV-8-seropositivity ranged from 18.1% in Kampala, Uganda, to 33.8% in North Mara, Tanzania, increasing steeply with age in all populations. Among adults, HHV-8-seropositivity ranged from 23.5% in Nigeria to 70.6% in rural West Nile, Uganda. It was higher in males and rural areas. Our data indicate that geographical exposures, gender, age, and factors correlated with rural residence impact HHV-8 seropositivity in sub-Saharan Africa.