Human Herpes virus-8 (HHV-8) is the known etiologic agent for several malignant pathologies, including Kaposi’s sarcoma (KS), the most common tumor in children in sub-Saharan Africa. Saliva is implicated as the culprit of transmission; however there is a paucity of information regarding transmission to young children. In this study, we investigated the hypothesis that household behaviors exposing the susceptible child to saliva increase the risk of transmission of HHV-8 to that child.
To test our hypothesis a large prospective cohort study in Lusaka, Zambia, enrolling 464 young children and their households, was followed for 48 months. Socio-demographics, health histories, feeding and child-rearing behaviors were assessed.
At enrollment, 75 HHV-8 positive children were analyzed for existing risk factors contributing to HHV-8 seropositivity. Analysis for independent variables found that for each additional HHV-8 positive household member, there was 2.5 greater odds for the child to be HHV-8 positive (P < 0.01). Of the household saliva sharing risk behaviors, a primary caregiver testing temperature of food prior to feeding to a child posed a 2.4 greater odds (P = 0.01). A child having been breastfed offered a decreased risk (OR 0.3, P < 0.01).
Of the enrolled children, 270 children were available for longitudinal analysis. Of these, 137 children seroconverted to become HHV-8 positive, an incidence of 29.94 per 100 child-years. Most significant independent behavioral risk factors for HHV-8 seroconversion included increased risk with current breastfeeding (HR 2.1, P = 0.002), increased risk with use of pacifier (HR 9.0, P = 0.01), and greater risk with household members blowing on food prior to sharing with child (HR 2.8, P = 0.05). Other studies in this report include development of an HHV-8 serodiagnostic assay.
Taken together, this report describes the epidemiology of HHV-8 transmission to a susceptible child within households, and the association with saliva sharing behaviors. Our results support the need for increased public awareness and education regarding risks of viral transmission with child-rearing behaviors that expose the child to saliva.