Brazil may have the highest absolute number of HTLV-I/II seropositive individuals in the world. Screening potential blood donors for HTLV-I/II is mandatory in Brazil. The public blood center network accounts for about 80.0% of all blood collected. We conducted a cross-sectional study to assess the geographic distribution of HTLV-I/II serological screening prevalence rates in blood donors from 27 large urban areas in the various States of Brazil, from 1995 to 2000. Enzyme immunoassay (EIA) was used to test for HTLV-I/II. The mean prevalence rates ranged from 0.4/1,000 in Florianópolis, capital of Santa Catarina State, in the South, to 10.0/1,000 in São Luiz, Maranhão State, in the Northeast. EIA prevalence rates are lower in the South and higher in the North and Northeast. The reasons for such heterogeneity may be multiple and need further studies.

a b s t r a c tEven though an estimated 10e20 million people worldwide are infected with the oncogenic retrovirus, human T-lymphotropic virus type 1 (HTLV-1), its epidemiology is poorly understood, and little effort has been made to reduce its prevalence. In response to this situation, the Global Virus Network launched a taskforce in 2014 to develop new methods of prevention and treatment of HTLV-1 infection and promote basic research. HTLV-1 is the etiological agent of two life-threatening diseases, adult T-cell leukemia and HTLV-associated myelopathy/tropical spastic paraparesis, for which no effective therapy is currently available. Although the modes of transmission of HTLV-1 resemble those of the more familiar HIV-1, routine diagnostic methods are generally unavailable to support the prevention of new infections. In * Corresponding author. Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics (GIGA) of University of Liege (ULg), B34, 1 Avenue de l'Hôpital, 4000, Sart-Tilman, Liege, Belgium.E-mail address: luc.willems@ulg.ac.be (L. Willems). Contents lists available at ScienceDirect Antiviral Researchj o u rn a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / a n t iv i r a l the present article, the Taskforce proposes a series of actions to expand epidemiological studies; increase research on mechanisms of HTLV-1 persistence, replication and pathogenesis; discover effective treatments; and develop prophylactic and therapeutic vaccines.

Background In Brazil nationally representative donor data are limited on HIV prevalence, incidence and residual transfusion risk. The objective of this study was to analyze HIV data obtained over 24 months by the REDS-II program in Brazil. Methods Donations reactive to 3rd and 4th generation immunoassays (IAs) were further confirmed by a less-sensitive (LS) IA algorithm and Western blot (WB). Incidence was calculated for first-time (FT) donors using the LS-EIA results and for repeat donors with a model developed to include all donors with a previous negative donation. Residual risk was projected by multiplying composite FT/repeat donor incidence rates by HIV marker-negative infectious window periods. Results HIV prevalence among FT donors was 92.2/105 donations. FT, repeat donor and composite incidence were 38.5 (95%CI: 25.6–51.4), 22.5 (95%CI: 17.6–28.0) and 27.5 (95%CI: 22.0–33.0) per 100,000 person-years, respectively. Male and community donors had higher prevalence and incidence rates than female and replacement donors. Estimated residual risk of HIV transfusion-transmission was 11.3 per 106 donations (95%CI: 8.4–14.2), which could be reduced to 4.2 per 106 donations (95%CI: 3.2–5.2) by use of individual donation nucleic acid testing (NAT). Conclusion Incidence and residual transfusion risk of HIV infection are relatively high in Brazil. Implementation of NAT testing will not be sufficient to decrease transmission rates to levels seen in the US or Europe, therefore other measures focused on decreasing donations by at-risk individuals are also necessary.

BACKGROUND-The profile of blood donors changed dramatically in Brazil over the past 20 years, from remunerated to non-remunerated and then from replacement to community donors. Donor demographic data from three major blood centers establish current donation profiles in Brazil, serving as baseline for future analyses and tracking longitudinal changes in donor characteristics.