The prevalence of human T-lymphotropic virus type 1 & 2 (HTLV-1/2) in South African blood donors

Background and objectives Donated blood is not currently screened for human T-cell lymphotropic virus (HTLV) in South Africa. Several small studies have detected HTLV-1 in South Africa, but prevalence by geographic region or population group is unavailable. Materials and Methods We performed a large seroprevalence study of South African blood donors during 3 months in 2013. All geographic regions except the Western Cape were included, and Black and Coloured (local term for mixed race) donors were oversampled. Identity-unlinked plasma samples were screened with the Abbott Prism HTLV-1/2 assay, and repeatedly reactive samples were tested by the Inno-LIA HTLV-1/2 Score confirmatory assay. Odds ratios were calculated with multivariable logistic regression. Results Of 46 752 donors tested, 133 (0 center dot 28%) were initially reactive, 111 (0 center dot 24%) repeatedly reactive and 57 (0 center dot 12%) confirmed positive for HTLV-1; none were HTLV-2 positive. Prevalence was 0 center dot 062% weighted to annual blood donations but highly concentrated in the Black population group (OR = 20 center dot 24 CI: 2 center dot 77-147 center dot 88); higher in females than males (OR = 1 center dot 81 CI: 1 center dot 06-3 center dot 08); and in donors aged >50 years compared to ages 16-19 (OR = 6 center dot 4 CI: 2 center dot 95-13 center dot 86). After controlling for age, sex and population group, there was no difference in prevalence between new and repeat blood donors or among geographic regions within South Africa. Conclusions We conclude that HTLV-1 infection is widespread among the Black population of South Africa and its epidemiology is similar to other endemic areas. Because South Africa is increasing its recruitment of Black blood donors, the implications for blood screening require further consideration.